Vendor

---
name: boris
description: |
  127 Claude Code workflow tips from Boris Cherny (creator of Claude Code) and the Claude Code team.
  PROACTIVE MODE: When the user is working on a task, check the CONTEXT MAP
  below and surface the most relevant tip BEFORE they ask. One tip at a time,
  short and actionable. Don't dump all tips — be a coach, not an encyclopedia.
  BROWSE MODE: When invoked with /boris, show the topic list and let the user pick.
  Use when: setting up Claude Code, optimizing workflows, running parallel sessions,
  configuring CLAUDE.md, using skills/commands, subagents, hooks, MCP integrations,
  worktrees, plan mode, verification, permissions, plugins, custom agents, sandboxing,
  keybindings, status lines, /simplify, /batch, /loop, /btw, /effort, /schedule,
  voice mode, remote control, auto mode, mobile app, session teleporting, Desktop app,
  Routines (scheduled/event-driven runs), /rewind, /compact vs /clear, auto-compact window,
  Opus 4.7 delegation model, full-context briefs, xhigh effort level,
  /fewer-permission-prompts, recaps, /focus, /go composite skill, adaptive thinking,
  4.6→4.7 behavioral shifts, task notifications, agent view (claude agents control plane),
  /goal (set a completion condition; Claude keeps working until it's met — Ralph loop built-in),
  Opus 4.8 (strongest coding model, more honest about its own work, catches bugs before declaring victory),
  high-effort default + xhigh for hard async work, raised Claude Code rate limits,
  fast mode for Opus 4.8 (research preview: 2.5x speed, 3x cheaper),
  dynamic workflows (research preview: hundreds of parallel subagents in one session for migrations / refactors / perf / batch bug fixes; activate by saying "use a workflow" in a prompt; orchestrator → implementer → verifiers → fixer pattern; Cat Wu's A/B-flag catalogue example),
  dynamic workflows deep-dive from Thariq + Sid (the three failure modes workflows fix — agentic laziness, self-preferential bias, goal drift; primitives agent/parallel/pipeline with schema/model/isolation; dynamic vs static harnesses; the six patterns — classify-and-act, fan-out-and-synthesize, adversarial verification, generate-and-filter, tournament, loop-until-done; use cases incl. Bun's Zig→Rust rewrite, deep research/verification, sorting 1000+ items, rule adherence, root-cause, triage; token budgets; pairing with /goal and /loop; saving and sharing workflows via skills; "ultracode" trigger),
  the Boris × Cat Wu one-year-after-GA interview (auto mode retired plan mode on Opus 4.6+; context minimalism — minimal system prompt + tools; write mistakes to CLAUDE.md or a skill instead of re-prompting; why auto mode is trustworthy — red-teamed into evals),
  nested subagents (agents kicking off agents, capped at depth=5, to manage context; monitor with arrow-down), the experimental fork: true skill frontmatter (run a skill in its own context window), and the refined "use a workflow" trigger,
  Claude Fable 5 (Mythos-class model launched June 9 2026, in Claude Code and Cowork; Boris's best coding model "by a wide margin" — less steering, better self-verification, longer sessions, higher autonomy; now the default coding model, superseding Opus 4.8),
  finding your unknowns (Thariq's field guide to clarifying what Claude doesn't know — the four unknowns; blindspot passes, brainstorms and prototypes, interviews, references, implementation plans, implementation notes, pitches and explainers, quizzes, before/during/after implementation),
  getting started with loops (the ClaudeDevs loop taxonomy — an agent repeating cycles until a stop condition; the four loop types turn-based, goal-based /goal, time-based /loop and /schedule, and proactive; verification skills, evaluator models, composing routines with dynamic workflows and auto mode; maintaining code quality and managing token usage with /usage and /workflows),
  /checkup (Boris's one-command setup tune-up — audits and cleans up unused skills/MCPs/plugins, dedups and slims a bloated CLAUDE.md, turns off slow hooks, updates Claude Code, enables auto mode, pre-approves frequently-denied read-only commands; confirms before changing anything and is fully reversible via one-line toggles and git-diff-reviewable CLAUDE.md edits),
  automation as infrastructure (Boris's thesis that the highest-leverage work is automating your own work — vim macros, lint rules, e2e tests — and now more so with agents: infra/DevX speeds up your whole fleet; move fixes from prompts into code so a class of issue is automated forever, which is what "loops" really means; and most importantly, encode domain knowledge as infrastructure — code comments, skills, CLAUDE.md, REVIEW.md, docs, memories — so agents and new contributors work with zero extra context; a rejected PR is a failure of automation),
  the new rules of context engineering for the Claude 5 generation (Thariq's field guide — the team deleted 80%+ of Claude Code's system prompt with no eval loss; six then→now shifts: give judgement not rules, design interfaces not examples, progressive disclosure over front-loading, simple tool descriptions over repetition, auto-memory over manual CLAUDE.md saves, rich references over simple specs; how to structure your own system prompt / CLAUDE.md / skills / references; the /doctor command to rightsize your setup), plus Opus 5 (state-of-the-art on coding + knowledge work, and Anthropic's least prompt-injectable model yet — alignment + PI probes + auto mode drive attack success to ~0).
author: Boris Cherny (tips)
source: howborisusesclaudecode.com
compiled-by: "@CarolinaCherry"
version: 8.13.0
date: 2026-07-24
user-invocable: true
---

# Boris Cherny's Claude Code Workflow Tips

> **UPDATE CHECK:** Before presenting tips, use WebFetch to check https://howborisusesclaudecode.com/api/version for the latest version. Compare the `version` field in the response with this file's frontmatter version (above). If the remote version is newer, **auto-update**: run `mkdir -p ~/.claude/skills/boris && curl -L -o ~/.claude/skills/boris/SKILL.md https://howborisusesclaudecode.com/api/install` via the Bash tool. Then tell the user: "Updated /boris skill from vX.X.X to vY.Y.Y. Type /boris again to use the new version." If versions match or the check fails, skip silently.

## How This Skill Works

**When invoked with `/boris`:** Show the topic list below and let the user browse.

**When working normally:** If you notice the user doing something where a Boris tip would help, mention it briefly. One sentence max. Example: "Tip from Boris: shift+tab into plan mode before multi-file changes (Section 3)." Don't interrupt flow — just nudge.

## Context Map — When to Surface Which Tip

Use this map to decide which tip is relevant to what the user is doing:

| User is doing... | Surface section | One-liner |
|---|---|---|
| Editing 3+ files | 3 (Plan Mode) | "Boris says: shift+tab into plan mode first" |
| Writing a hook or asking about hooks | 7, 24, 49 (Hooks) | "Boris has hook patterns for this — want to see?" |
| Setting up CLAUDE.md or project rules | 4 (CLAUDE.md) | "Boris: 'Anytime Claude does something wrong, add it to CLAUDE.md'" |
| Creating a skill or slash command | 5 (Skills) | "Boris turns anything he does 2x/day into a slash command" |
| Spawning subagents or parallel work | 1, 6, 55 (Parallel/Subagents) | "Boris runs 3-5 worktrees at once — the biggest productivity unlock" |
| Connecting MCP servers | 9 (MCP) | "Boris uses Slack + BigQuery MCPs for cross-tool context" |
| Debugging a tricky bug | 12, 14 (Bug Fixing/Verification) | "Boris: always verify. 'Did this actually work?'" |
| Running long tasks or crons | 13, 31, 43, 48 (Long-Running/Loop/Schedule) | "Boris uses /loop for recurring checks and /schedule for cloud jobs" |
| Reviewing code or PRs | 32 (Code Review) | "Boris has agents that review code and hunt for bugs" |
| Asking a side question mid-task | 33, 54 (/btw) | "Use /btw — it asks without interrupting your current task" |
| Configuring permissions or security | 8, 20, 21 (Permissions/Sandboxing) | "Boris manages permissions in CLAUDE.md, not interactively" |
| Customizing terminal/UI | 11, 16, 22, 23, 25, 26, 27, 40 (Terminal/UI) | "Boris customizes spinner verbs, colors, and status lines" |
| Using plugins or extensions | 18, 51 (Plugins/Chrome) | "Boris uses plugins to extend Claude's reach" |
| Building custom agents | 19, 59 (Custom Agents) | "Boris builds --agent custom agents with tailored system prompts" |
| Choosing model or effort level | 2, 17, 34 (Model/Effort) | "Boris: /effort max for hard debugging, default for everything else" |
| Working on mobile or remote | 35, 44, 46, 47, 50 (Remote/Mobile) | "Boris teleports sessions between devices with --teleport" |
| Writing a setup or deploy script | 37 (Setup Scripts) | "Boris has setup scripts for cloud environments" |
| Wanting to try voice input | 36, 60 (Voice) | "Boris uses /voice for hands-free input" |
| Doing a large refactor or migration | 29, 30, 56 (Simplify/Batch) | "Boris uses /batch to fan out changes across many files" |
| Forking or branching work | 28, 53 (Worktrees/Fork) | "Boris forks sessions to explore alternatives without losing progress" |
| Working across multiple repos | 58 (--add-dir) | "Boris uses --add-dir to give Claude access to related repos" |
| Optimizing SDK/startup performance | 57 (--bare) | "Boris uses --bare for 10x faster SDK startup" |
| Setting up auto mode | 42 (Auto Mode) | "Auto mode skips permission prompts for safe operations" |
| Configuring memory or context | 45 (Auto-Memory) | "Boris uses auto-memory and auto-dream for persistent context" |
| Wanting scheduled or event-driven runs | 31, 43, 61 (Loop/Schedule/Routines) | "Routines runs Claude on cron or GitHub events — no laptop needed" |
| Claude went down a wrong path | 62 (Rewind) | "Thariq: rewind over correcting — double-Esc drops the failed attempt from context" |
| Session is getting long / shedding context | 63 (/compact vs /clear) | "/compact is a lossy summary; /clear is a hand-written brief. Rule: new task = /clear" |
| Context feels rotten / model acting dumb | 64 (Auto-compact window) | "Context rot at 300-400k — set CLAUDE_CODE_AUTO_COMPACT_WINDOW=400000" |
| Micromanaging Claude step-by-step on Opus 4.7 | 65 (Delegation over Guidance) | "Cat: treat Opus 4.7 like an engineer you delegate to, not a pair programmer" |
| Writing a prompt for a substantial task | 66 (Full Task Context Upfront) | "Include goal + constraints + acceptance criteria in the first turn" |
| Tuning reasoning depth on Opus 4.7 | 67, 72 (xhigh / Effort Mastery) | "Default is now xhigh. Max is session-only. Use /effort to adjust" |
| Running long autonomous tasks on 4.7 | 68 (Auto Mode + Parallel Claudes) | "Auto mode + parallel Claudes — no more babysitting permission prompts" |
| Getting too many permission prompts | 69 (/fewer-permission-prompts) | "Run /fewer-permission-prompts to scan history and tune your allowlist" |
| Returning to a session after being away | 70 (Recaps) | "Recaps summarize what happened and what's next — check when you come back" |
| Wanting less visual noise from Claude | 71 (Focus Mode) | "/focus hides intermediate work, shows only the final result" |
| Shipping a complete feature end-to-end | 73 (/go) | "Boris: 'Claude do blah blah /go' — test + simplify + PR in one skill" |
| Upgrading from Opus 4.6 to 4.7 | 74 (What Changed) | "Three shifts: calibrated response length, less auto-tool-use, judicious subagents" |
| Juggling many concurrent Claude sessions | 76 (Agent View) | "Run `claude agents` from your root code dir — one list of all sessions grouped by status" |
| Claude stops too early on a long task | 77 (/goal) | "Set a completion condition with /goal — Claude keeps working until it's met" |
| Just upgraded to Opus 4.8 / asking what's new | 78 (Opus 4.8) | "4.8 is more honest about its own work — flags uncertainty, catches its own bugs before declaring victory" |
| Tuning effort or rate limits on 4.8 | 79 (High-Effort Default + xhigh) | "4.8 defaults to high effort (same tokens as 4.7's default, better output); use xhigh for hard async runs" |
| Planning a big migration, refactor, perf pass, or batch bug fix | 80, 93 (Dynamic Workflows) | "Say 'use a workflow' to activate dynamic workflows — Claude fans out into N parallel tasks; default to auto mode so it doesn't stop for permissions" |
| Asking how workflows work, or building/reusing one | 81-86 (Dynamic Workflows deep-dive) | "Workflows fix laziness, bias, and drift by giving separate agents isolated goals — six patterns to compose (fan-out, adversarial verify, tournament, loop-until-done); cap tokens, pair with /goal + /loop, save via skills" |
| Verifying claims, sorting 1000+ items, triage, root-cause, rule adherence | 84 (Workflow use cases) | "These are workflow sweet spots — one agent per claim/item, adversarial verification, comparative judgment over absolute scoring" |
| Reaching for plan mode on Opus 4.6+ | 87 (Auto Mode Retired Plan Mode) | "Boris dropped plan mode — 4.6+ don't need a planning step. Use auto mode and move on" |
| Writing a long system prompt or tool list | 88 (Context Minimalism) | "Tell the model less — minimal prompt + a way to pull context, then get out of the way" |
| Claude repeats the same mistake across runs | 89 (Write It Down) | "Don't re-prompt — write the fix to CLAUDE.md or a skill so it never recurs" |
| Unsure whether auto mode is safe | 90 (Why Auto Mode Is Trustworthy) | "It's red-teamed into evals — and safer than glazing over every permission prompt" |
| Wanting agents to spawn their own agents / deep context isolation | 91 (Nested Subagents) | "Nested subagents shipped — agents kick off agents (depth=5) to manage context. Watch them with arrow-down in the terminal" |
| A heavy skill blowing out the main context | 92 (fork: true) | "Experimental: add fork: true to the skill's frontmatter so it runs in its own context window" |
| Trying to trigger a dynamic workflow | 93 (Workflow Trigger) | "Say 'use a workflow' — bare 'workflow' had too many false positives" |
| Picking a model / asking what's the best for coding | 2, 94 (Fable 5) | "Fable 5 is the new best coding model — Boris: best he's used, 'by a wide margin'" |
| Wondering how Fable 5 changes the workflow | 95 (What Fable 5 Changes) | "New default; leans into context minimalism + delegation; pairs with the autonomy stack" |
| Starting work in an unfamiliar codebase or domain | 96–99 (Finding Your Unknowns) | "Ask Claude for a 'blindspot pass' to surface your unknown unknowns before you prompt" |
| Struggling to describe what you want | 97 (Before Implementation) | "Prototype it — an HTML artifact you react to beats describing it; or point Claude at reference source code" |
| Mid-implementation and the agent is deviating | 98 (During Implementation) | "Have Claude keep an implementation-notes.md logging deviations, so the next attempt is smoother" |
| Needing buy-in or to truly understand a big change | 99 (After Implementation) | "Build a pitch doc (lead with the demo); have Claude quiz you — merge only when you pass" |
| Asking what a "loop" is / how to run agents in loops | 100 (The Four Loops) | "Four loop types — turn-based, goal-based, time-based, proactive — differ by trigger, stop condition, and how much you hand off" |
| Running a real-time task that needs iteration | 101 (Loops You Drive) | "Encode verification as a skill for turn-based loops; use /goal to define done so Claude can't stop early" |
| Wanting work to run on a schedule or without you | 102 (Autonomous Loops) | "/loop and /schedule for recurring work; compose /schedule + /goal + skills + dynamic workflows + auto mode for proactive loops" |
| Worried about loop quality or token cost | 103 (Making Loops Good) | "Clean codebase + verification + second-agent review; right primitive/model, clear stop criteria, pilot first, check /usage and /workflows" |
| Setup feels bloated / slow / cluttered with unused stuff | 104 (/checkup) | "Run /checkup — it audits unused skills/MCPs/plugins, a bloated CLAUDE.md, slow hooks, stale version, and cleans up after confirming" |
| Nervous about letting a command change your config | 105 (/checkup is Safe) | "/checkup confirms before touching anything and is fully reversible — one-line toggles + CLAUDE.md edits you review in git diff" |
| Wondering if cleanup is actually worth it | 106 (/checkup Findings) | "Boris's run found a broken launcher, 38 skills unused in 2,345 sessions, ~10k-token CLAUDE.md — cleanup saved ~5.5k tokens/session" |
| Looking for the highest-leverage thing to do | 107 (Automation Is the Meta-Skill) | "Automate your own work — with a fleet of agents, every automation multiplies across all of them" |
| Fixing the same kind of issue over and over | 108 (Fixes Into Code) | "Don't re-fix it each run — have Claude write a lint rule / CI step / routine so the class is automated forever (that's what loops means)" |
| Onboarding people / agents to a codebase | 109 (Domain Knowledge as Infra) | "Encode domain knowledge as CLAUDE.md, REVIEW.md, skills, docs — a rejected PR is a failure of automation" |
| Writing hard DO/DON'T rules into CLAUDE.md or a skill | 110 (Give Judgement, Not Rules) | "For Claude 5, delete the guardrail and let judgement handle it — the team cut 80%+ of the system prompt with no eval loss" |
| Writing tool descriptions or designing a tool/script | 111 (Design Interfaces, Not Examples) | "Examples fence Claude in — make parameters expressive instead (a status enum + one constraint teaches usage without examples)" |
| A bloated system prompt / CLAUDE.md / skill; front-loading everything | 112 (Progressive Disclosure) | "Load context when it's needed — skills over baked-in steps, deferred tool loading, a tree of files; and put tool instructions only in the tool description" |
| Hand-curating CLAUDE.md, or pointing Claude at a plain markdown spec | 113 (Auto-Memory & Rich References) | "Memory is automatic now; and reference HTML artifacts, code, test suites, and rubrics instead of simple specs" |
| Structuring context for Claude Code or your own agent | 114 (Applying It / /doctor) | "Keep CLAUDE.md to purpose + gotchas, skills as lightweight guides, prefer code references — and run /doctor to rightsize automatically" |
| Asking what's new in Opus 5 / worried about prompt injection | 115 (Opus 5) | "SOTA on coding + knowledge work, and the least prompt-injectable model yet — alignment + PI probes + auto mode drive attack success to ~0" |

## Topic List (127 tips across 115 sections)

When the user runs `/boris`, present this list and ask what they want to explore:

1. Parallel Execution (worktrees, web/mobile sessions)
2. Model Selection (Opus for everything)
3. Plan Mode (shift+tab, pour energy into the plan)
4. CLAUDE.md Best Practices (team rules, @.claude in PRs)
5. Skills & Slash Commands (reusable workflows)
6. Subagents (delegate to specialists)
7. Hooks (automate on events)
8. Permissions (manage access)
9. MCP Integrations (Slack, BigQuery, external tools)
10. Prompting Tips (be specific, show examples)
11. Terminal Setup (iTerm2, tmux, tabs)
12. Bug Fixing (isolate, reproduce, verify)
13. Long-Running Tasks (background, notifications)
14. Verification — The #1 Tip ("Did it actually work?")
15. Learning with Claude (teach it, learn from it)
16-27. Terminal Config, Effort, Plugins, Agents, Permissions, Sandboxing, Status Line, Keybindings, Hooks (Advanced), Spinner Verbs, Output Styles, Customize Everything
28. Git Worktree Support (CLI, Desktop, subagents)
29-30. /simplify and /batch
31-33. /loop, Code Review Agents, /btw
34-41. /effort max, Remote Control, Voice, Setup Scripts, Session Naming, /color, PostCompact Hook
42-45. Auto Mode, /schedule, iMessage Plugin, Auto-Memory & Auto-Dream
46-60. Mobile App, Teleporting, Hooks Lifecycle, Cowork Dispatch, Chrome Extension, Desktop App, Fork Sessions, --bare, --add-dir, --agent, /voice
61-64. Routines, Rewind, /compact vs /clear, Auto-Compact Window
65-67. Delegation over Guidance, Full Task Context Upfront, xhigh effort level
68-75. Auto Mode + Parallel Claudes, /fewer-permission-prompts, Recaps, Focus Mode, Effort Mastery, /go Composite Skill, 4.6→4.7 Behavioral Shifts, Task Notifications
76. Agent View (claude agents control plane — many sessions, one list)
77. /goal (set a completion condition; Claude keeps working until it's met)
78. Opus 4.8 (strongest coding model yet; honest about its own work; same price as 4.7)
79. High-Effort Default + xhigh + Raised Rate Limits (4.8 defaults to high; xhigh for hard async work)
80. Dynamic Workflows (research preview; hundreds of parallel subagents in a single session for the biggest jobs)
81. Why Workflows — Three Failure Modes (agentic laziness, self-preferential bias, goal drift)
82. Workflow Primitives (agent/parallel/pipeline; schema, model, isolation; dynamic vs static)
83. The Six Workflow Patterns (classify-and-act, fan-out-and-synthesize, adversarial verification, generate-and-filter, tournament, loop-until-done)
84. Workflow Use Cases (Bun's Zig→Rust rewrite, deep research/verification, sorting, rule adherence, root-cause, triage)
85. Pairing Workflows with /goal, /loop, and Token Budgets (and when not to use one)
86. Saving and Sharing Workflows (press "s", ~/.claude/workflows, distribute via a skill, "ultracode")
87. Auto Mode Retired Plan Mode (Boris dropped plan mode for auto mode on Opus 4.6+)
88. Context Minimalism (minimal system prompt + tools; prompt eng → context eng → minimalism)
89. Write It Down, Don't Re-Prompt (every mistake → CLAUDE.md or a skill, so Claude runs forever)
90. Why Auto Mode Is Trustworthy (thousands of transcripts, red-team, evals; safer than glazing over prompts)
91. Nested Subagents (agents kick off agents, depth=5; manage context by nesting; monitor with arrow-down)
92. fork: true (experimental — run a skill in its own context window; pair with per-step agents)
93. The Workflow Trigger Is Now "use a workflow" (bare "workflow" had too many false positives)
94. Fable 5 (Anthropic's "Mythos-class" model; best coding model "by a wide margin"; in Claude Code + Cowork)
95. What Fable 5 Changes (new default coding model; leans into minimalism + delegation; pairs with the autonomy stack)
96. The Four Unknowns (known knowns / known unknowns / unknown knowns / unknown unknowns — the map vs the territory)
97. Finding Unknowns Before Implementation (blindspot pass, brainstorms & prototypes, interviews, references, implementation plans)
98. Finding Unknowns During Implementation (implementation-notes.md — log deviations, keep going, learn for next time)
99. Finding Unknowns After Implementation (pitches & explainers, quizzes — merge only when you pass)
100. The Four Loops (turn-based, goal-based, time-based, proactive — by trigger, stop condition, and what you hand off)
101. Loops You Drive (turn-based agentic loop + verification skills; goal-based /goal with an evaluator model)
102. Autonomous Loops (time-based /loop & /schedule; proactive loops composing schedule + /goal + workflows + auto mode)
103. Making Loops Good (code quality: clean codebase, verification, second-agent review; token usage: right primitive/model, pilot, /usage, /workflows)
104. /checkup — The One-Command Tune-Up (audits unused skills/MCPs/plugins, dedups & slims CLAUDE.md, turns off slow hooks, updates Claude Code, enables auto mode, pre-approves read-only commands)
105. /checkup is Safe by Default (confirms before changing anything; fully reversible — one-line setting toggles and CLAUDE.md edits you review in git diff; scope options from "clean everything" to "report only")
106. /checkup — The Run (Boris's real result: broken launcher, 38 skills unused in 2,345 sessions, ~10k-token CLAUDE.md; cleanup repairs the install and saves ~5.5k tokens/session)
107. Automation Is the Meta-Skill (the highest-leverage work is automating your own work — vim/lint/e2e; with an agent fleet every automation multiplies across all agents)
108. Move Fixes From Prompts Into Code (don't re-fix an issue each run — have Claude write a lint rule / CI step / routine so the class is automated forever; what "loops" really means)
109. Encode Domain Knowledge as Infrastructure (CLAUDE.md, REVIEW.md, skills, docs, comments, memories so agents & new contributors work with zero extra context; a rejected PR is a failure of automation)
110. Give Judgement, Not Rules (Claude 5 reads surrounding context and decides — swap rigid guardrails for judgement; the team cut 80%+ of Claude Code's system prompt with no eval loss)
111. Design Interfaces, Not Examples (examples constrain the exploration space; expressive parameters — a status enum + one constraint, like TodoWrite — teach usage without them)
112. Progressive Disclosure Over Front-Loading (load context when relevant: verification/review as skills, deferred tool loading via ToolSearch, a tree of files; and put tool instructions in the tool description only)
113. Auto-Memory & Rich References (Claude auto-saves memories now; references go beyond markdown specs — HTML artifacts, code as spec, test suites, and rubrics checked by verifier agents)
114. Applying It to Your Own Context (the assembled stack; keep CLAUDE.md to purpose + gotchas, skills as lightweight guides, prefer code references; run /doctor to rightsize skills & CLAUDE.md)
115. Opus 5 (state-of-the-art on coding + knowledge-work evals, and Anthropic's least prompt-injectable model yet — alignment + PI probes + auto mode drive attack success to ~0)

---

**127 tips** across 115 topics, sourced from Boris Cherny (creator of Claude Code) and the Claude Code team at Anthropic. All tips are contained in this file — do not fetch from the website.

**Parts:** The tips were shared across 22 threads:
- **Part 1** (Jan 2, 2026, 13 tips): Sections 1–14 — parallel execution, web/mobile, Opus, CLAUDE.md, @.claude, plan mode, slash commands, subagents, hooks, permissions, MCP, long-running tasks, verification
- **Part 2** (Jan 31, 2026, 10 tips): Sections 1, 3, 4, 5, 12, 10, 11, 6, 9, 15 — deeper dives on parallel work, plan mode, CLAUDE.md, skills, bug fixing, prompting, terminal setup, subagents, data/analytics, learning
- **Part 3** (Feb 11, 2026, 12 tips): Sections 16–27 — terminal config, effort level, plugins, custom agents, permissions management, sandboxing, status line, keybindings, hooks (advanced), spinner verbs, output styles, customize everything
- **Part 4** (Feb 20, 2026, 5 tips): Section 28 — built-in worktree support (CLI, Desktop, subagents, custom agents, non-git VCS)
- **Part 5** (Feb 27, 2026, 2 tips): Sections 29–30 — /simplify and /batch
- **Part 6** (Mar 7–10, 2026, 3 tips): Sections 31–33 — /loop for scheduled recurring tasks, code review agents, /btw for mid-task questions
- **Part 7** (Mar 13, 2026, 8 tips): Sections 34–41 — /effort max, remote control sessions, voice mode, setup scripts, session naming, /color, PostCompact hook
- **Part 8** (Mar 23–25, 2026, 4 tips): Sections 42–45 — auto mode, /schedule cloud jobs, iMessage plugin, auto-memory & auto-dream
- **Part 9** (Mar 29, 2026, 15 tips): Sections 46–60 — mobile app, session teleporting, /loop & /schedule, hooks lifecycle, Cowork Dispatch, Chrome extension, Desktop app, fork sessions, /btw, git worktrees, /batch, --bare, --add-dir, --agent, /voice
- **Part 10** (Apr 14–16, 2026, 7 tips): Sections 61–67 — Routines (scheduled/event-driven Claude Code), /rewind over correcting, /compact vs /clear, CLAUDE_CODE_AUTO_COMPACT_WINDOW, delegation over guidance for Opus 4.7, full task context upfront, xhigh effort level
- **Part 11** (Apr 16–17, 2026, 8 tips): Sections 68–75 — auto mode + parallel Claudes, /fewer-permission-prompts, recaps, focus mode, effort mastery (xhigh/max/adaptive), /go composite skill, 4.6→4.7 behavioral shifts, task completion notifications
- **Part 12** (May 11–12, 2026, 2 tips): Section 76 — Agent View, the native control plane for managing multiple Claude Code sessions (research preview launched May 11 from @bcherny / @trq212 / @_catwu / @dickson_tsai); Section 77 — /goal, a completion-condition slash command (Ralph loop built into Claude Code; surfaced by @ClaudeDevs on May 12, described as recently shipped, exact ship date pending changelog confirmation)
- **Part 13** (May 28, 2026, 3 tips): Section 78 — Opus 4.8, strongest coding model yet (SWE-Bench Pro 64.3 → 69.2, more honest about its own work, same price as 4.7); Section 79 — High-Effort Default + xhigh + raised Claude Code rate limits (4.8 defaults to high effort, switch to xhigh for hard async work); Section 80 — Dynamic Workflows, research preview that runs hundreds of parallel subagents in a single session for tasks too big for one pass (save for migrations, refactors, perf optimization, batch bug fixes; activated by mentioning the word "workflow" in a prompt — later refined to "use a workflow", see Section 93; orchestrator → implementer → verifiers → fixer pattern). Sources: four posts from [@bcherny](https://x.com/bcherny/status/2060048873440129073) on the launch, plus [@_catwu](https://x.com/_catwu/status/2060054180379689074) on the activation trigger, orchestrator diagram, and a real A/B-flag catalogue example.
- **Part 14** (June 2, 2026, 6 tips): Sections 81–86 — the dynamic-workflows practitioner's guide from [@trq212](https://x.com/trq212/status/2061907337154367865) and @sidbid (the engineers who built the feature; also on the Claude Blog). Section 81 — the three failure modes workflows fix (agentic laziness, self-preferential bias, goal drift); Section 82 — the primitives (agent/parallel/pipeline with schema, model, isolation) and dynamic vs static harnesses; Section 83 — the six patterns Claude composes (classify-and-act, fan-out-and-synthesize, adversarial verification, generate-and-filter, tournament, loop-until-done); Section 84 — use cases, often non-coding (Bun's Zig→Rust rewrite, deep research/verification, sorting 1000+ items, rule adherence, root-cause, triage with quarantine); Section 85 — token budgets, pairing with /goal and /loop, quick workflows, and when not to use one; Section 86 — saving (press "s") and sharing workflows via skills, plus the "ultracode" trigger.
- **Part 15** (June 8, 2026, 4 tips): Sections 87–90 — from *"Reflecting on a year of Claude Code,"* a one-year-after-GA conversation between [@bcherny](https://x.com/bcherny/status/2064034799711588805) (Boris Cherny, Head of Claude Code) and [@_catwu](https://x.com/_catwu) (Cat Wu, Head of Product, Claude Code). Section 87 — auto mode retired plan mode (4.6+ don't need a planning step); Section 88 — context minimalism (prompt engineering → context engineering → minimal system prompt + tools, let the model pull what it needs); Section 89 — when Claude errs, write the fix to CLAUDE.md or a skill instead of re-prompting, so it runs forever; Section 90 — why auto mode is trustworthy (thousands of transcripts classified, red-teamed into evals; safer than glazing over every prompt). Sources: [@bcherny's launch tweet](https://x.com/bcherny/status/2064034799711588805) and the [YouTube interview](https://www.youtube.com/watch?v=Hth_tLaC2j8).
- **Part 16** (June 9, 2026, 3 tips): Sections 91–93 — from [@bcherny's nested-subagents thread](https://x.com/bcherny/status/2064327225504403752). Section 91 — nested subagent support (agents kicking off agents, capped at depth=5, as a way to manage context; monitor with arrow-down in the terminal; model propagates but thinking weights don't yet; works with forked sessions and Chrome); Section 92 — the experimental `fork: true` skill frontmatter (run a skill in its own context window, pair with per-step agents; being added to the built-in `/code-review`); Section 93 — the dynamic-workflows trigger refined to "use a workflow" (bare "workflow" had too many false positives), which updates the Part 13/14 activation guidance.
- **Part 17** (June 9, 2026, 2 tips): Sections 94–95 — the **Claude Fable 5** launch from [@bcherny](https://x.com/bcherny/status/2064402671898075579) and [@claudeai](https://x.com/claudeai/status/2064394151441863006). Section 94 — Fable 5, a "Mythos-class" model now in Claude Code and Cowork, which Boris calls the best coding model he's used "by a wide margin" (fewer steers, more efficient tokens, better code/tool use, more intelligent self-verification, longer sessions, higher trust & autonomy); benchmarks published (SWE-Bench Pro 80.3% vs Opus 4.8's 69.2%, SOTA on nearly all), priced at $10/M in · $50/M out (2× Opus 4.8), model id `claude-fable-5`, 1M context, 128K output, adaptive thinking. Section 95 — what it changes (new default coding model superseding Opus 4.8, leans into context minimalism + delegation, pairs with the autonomy stack; Fable-specific effort/usage tactics still emerging).
- **Part 18** (July 3, 2026, 4 tips): Sections 96–99 — *"A Field Guide to Fable: Finding Your Unknowns,"* from [@trq212](https://x.com/trq212/status/2073100352921215386?s=51) (Thariq, Claude Code). The frame: the map (your prompts, skills, context) is not the territory (the codebase and its real constraints); the gap is your *unknowns*, and with Fable the work is bottlenecked by your ability to clarify them. Section 96 — the four unknowns (known knowns, known unknowns, unknown knowns, unknown unknowns); reducing and planning for them is the skill of agentic coding. Section 97 — before implementation: blindspot pass (surface unknown unknowns), brainstorms & prototypes (HTML artifacts for unknown knowns), interviews (one question at a time, architecture-changing first), references (best reference is source code), implementation plans (lead with what's most likely to change). Section 98 — during implementation: an `implementation-notes.md` where the agent logs deviations and keeps going (pairs with Section 89, "write it down"). Section 99 — after implementation: pitches & explainers (package prototype + spec + notes, lead with the demo, for buy-in) and quizzes (have Claude quiz you on the change; merge only when you pass). Capstone: the Fable launch video was edited entirely by Claude Code using this exact loop.
- **Part 19** (July 6, 2026, 4 tips): Sections 100–103 — *"Getting started with loops,"* from [@ClaudeDevs](https://x.com/ClaudeDevs/status/2074208949205881033?s=51) (written by @delba_oliveira). Defines a loop as an agent repeating cycles of work until a stop condition is met, categorized by trigger, stop, primitive, and task type. Section 100 — the four loop types (turn-based, goal-based, time-based, proactive) and how you hand off progressively more (the check → stop condition → trigger → prompt). Section 101 — loops you drive: the turn-based agentic loop improved by encoding verification as a SKILL.md, and goal-based /goal where an evaluator model checks your condition until the goal is met or a turn cap is hit. Section 102 — autonomous loops: time-based /loop (local) and /schedule (cloud Routine) for recurring or external-system work, and proactive loops that compose /schedule + /goal + skills + dynamic workflows + auto mode to run event-driven with no human. Section 103 — making loops good: code quality (clean codebase, verification skills, reachable docs, second-agent /code-review) and token usage (right primitive/model, clear stop criteria, pilot before a large run, scripts for deterministic work, don't over-schedule, review with /usage and /workflows), plus a "which loop when" decision table.
- **Part 20** (July 8, 2026, 3 tips): Sections 104–106 — *"New in Claude Code: /checkup,"* from [@bcherny](https://x.com/bcherny/status/2074997571563479143). A single command that audits and cleans up your whole Claude Code setup. Section 104 — what /checkup does: cleans up unused skills/MCPs/plugins to save context, dedups your local CLAUDE.md against the checked-in one, breaks up a big root CLAUDE.md into nested CLAUDE.md's + skills, turns off slow hooks, updates Claude Code to the latest version, enables auto mode by default, and pre-approves frequently-denied read-only commands (plus "a few other goodies"). Section 105 — safe by default: it confirms before making any changes and everything is reversible (settings changes are one-line toggles; CLAUDE.md edits stay in your working tree for `git diff` review), with scope options ranging from "clean up everything" to "let me pick" to "report only." Section 106 — the run: Boris posted his own /checkup output, which found his `claude` command broken (a test run overwrote its launcher), 38 project skills never used across 2,345 sessions, and a CLAUDE.md loading ~10k tokens every session — cleaning it all up repairs the install and saves roughly 5.5k tokens of context per session.
- **Part 21** (July 15, 2026, 3 tips): Sections 107–109 — *"Automation as infrastructure,"* an essay from [@bcherny](https://x.com/bcherny/status/2077460395279692197) on why automating your own work is the highest-leverage thing an engineer can do, now more than ever. Section 107 — automation is the meta-skill: the best engineers always automated (vim/emacs macros, lint rules, e2e suites) because it multiplied their output; with an army of agents each automation is multiplied across all of them (more automation = more output per unit time). Section 108 — move fixes from prompts into code: an agent fixing an issue every time it appears burns tokens and misses cases, so have Claude write a lint rule, CI step, or routine to automate the whole class forever — "what people are talking about when they talk about loops" (generalizes Section 89, write it down). Section 109 — encode domain knowledge as infrastructure (the most important): automation is what lets others contribute (engineers day-one, non-engineers as effectively as engineers); the blocker is domain knowledge living in people's heads, and what's changed is that nearly all of it can now be encoded as code comments, skills, CLAUDE.md, REVIEW.md, docs, and memories so agents work with zero additional context — "a rejected PR is a failure of automation." Every team should write the CLAUDE.md's, REVIEW.md's, skills, and docs that let agents work in their codebase with no extra prompting.
- **Part 22** (July 24, 2026, 6 tips): Sections 110–115 — *"The new rules of context engineering for Claude 5 generation models,"* from [@trq212](https://x.com/trq212/status/2080710971228918066?s=51) (Thariq, Claude Code; also on the [Claude blog](https://claude.com/blog/the-new-rules-of-context-engineering-for-claude-5-generation-models)), landing alongside the **Opus 5** launch from [@bcherny](https://x.com/bcherny/status/2080713091688583312). Tuning Claude Code for the Claude 5 generation, the team removed over 80% of the system prompt with no measurable loss on coding evals; the through-line is to stop over-constraining the model and let judgement work. Section 110 — give judgement, not rules (the comment-guidance example: "default to no comments / one short line max" → "write code that reads like the surrounding code: match its comment density, naming, and idiom"; a rule right 90% of the time is wrong the rest, judgement handles both). Section 111 — design interfaces, not examples (examples fence Claude into the demonstrated space; make parameters expressive — TodoWrite's status enum pending/in_progress/completed plus "only one in_progress" teaches usage with no example; an HTML mockup beats a described design). Section 112 — progressive disclosure over front-loading (verification/code-review moved into skills Claude calls selectively; tools use deferred loading via ToolSearch; a tree of files loaded at the right time instead of one mega CLAUDE.md; and stop repeating yourself — tool instructions live in the tool description only). Section 113 — auto-memory (Claude now auto-saves memories relevant to the work and to you, across sessions) and rich references (beyond markdown specs: HTML artifacts, code as spec, detailed test suites, and rubrics that verifier agents in a dynamic workflow check against). Section 114 — applying it to your own context (the assembled stack: prompt → references → system prompt → CLAUDE.md → skills → memory; keep CLAUDE.md to purpose + gotchas, skills as lightweight guides, prefer code references; run `/doctor` / `claude doctor` to rightsize automatically). Section 115 — Opus 5: state-of-the-art on coding + knowledge-work evals, and the least prompt-injectable model yet — layering alignment + prompt-injection probes + auto mode drives attack success to ~0, the trust foundation the new rules depend on.

---

## 1. Parallel Execution

### Run Multiple Claude Sessions in Parallel
The single biggest productivity unlock. Spin up 3-5 git worktrees at once, each running its own Claude session.

```bash
# Create a worktree
git worktree add .claude/worktrees/my-worktree origin/main

# Start Claude in it
cd .claude/worktrees/my-worktree && claude
```

**Why worktrees over checkouts:** The Claude Code team prefers worktrees - it's why native support was built into the Claude Desktop app.

**Pro tips:**
- Name your worktrees and set up shell aliases (za, zb, zc) to hop between them in one keystroke
- Have a dedicated "analysis" worktree just for reading logs and running BigQuery
- Use iTerm2/terminal notifications to know when any Claude needs attention
- Color-code and name your terminal tabs, one per task/worktree

### Web and Mobile Sessions
Beyond the terminal, run additional sessions on claude.ai/code. Use:
- `&` command to background a session
- `--teleport` flag to switch contexts between local and web
- Claude iOS app to start sessions on the go, pick them up on desktop later

---

## 2. Model Selection

### Use Opus 4.5 with Thinking for Everything
Boris's reasoning: "It's the best coding model I've ever used, and even though it's bigger & slower than Sonnet, since you have to steer it less and it's better at tool use, it is almost always faster than using a smaller model in the end."

**The math:** Less steering + better tool use = faster overall results, even with a larger model.

**Update (June 9, 2026):** **Claude Fable 5** is now Boris's top coding model — *"the best model I have used for coding, by a wide margin"* (Section 94). It supersedes Opus as the default for coding; the same "steer it less" logic applies, only more so.

---

## 3. Plan Mode

### Start Every Complex Task in Plan Mode
Press `shift+tab` to cycle to plan mode. Pour your energy into the plan so Claude can 1-shot the implementation.

**Workflow:** Plan mode -> Refine plan -> Auto-accept edits -> Claude 1-shots it

**Team patterns:**
- One person has one Claude write the plan, then spins up a second Claude to review it as a staff engineer
- The moment something goes sideways, switch back to plan mode and re-plan
- Explicitly tell Claude to enter plan mode for verification steps, not just for the build

"A good plan is really important to avoid issues down the line."

---

## 4. CLAUDE.md Best Practices

### Invest in Your CLAUDE.md
Share a single CLAUDE.md file for your repo, checked into git. The whole team should contribute.

**Key practice:** "Anytime we see Claude do something incorrectly we add it to the CLAUDE.md, so Claude knows not to do it next time."

**After every correction:** End with "Update your CLAUDE.md so you don't make that mistake again." Claude is eerily good at writing rules for itself.

**Advanced:** One engineer tells Claude to maintain a notes directory for every task/project, updated after every PR. They then point CLAUDE.md at it.

### @.claude in Code Reviews
Tag @.claude on PRs to add learnings to the CLAUDE.md as part of the PR itself. Use the Claude Code GitHub Action (`/install-github-action`) for this.

Example PR comment:
```
nit: use a string literal, not ts enum

@claude add to CLAUDE.md to never use enums,
always prefer literal unions
```

This is "Compounding Engineering" - Claude automatically updates the CLAUDE.md with the learning.

---

## 5. Skills & Slash Commands

### Create Your Own Skills
Create skills and commit them to git. Reuse across every project.

**Team tips:**
- If you do something more than once a day, turn it into a skill or command
- Build a `/techdebt` slash command and run it at the end of every session to find and kill duplicated code
- Set up a slash command that syncs 7 days of Slack, GDrive, Asana, and GitHub into one context dump
- Build analytics-engineer-style agents that write dbt models, review code, and test changes in dev

### Slash Commands for Inner Loops
Use slash commands for workflows you do many times a day. Commands are checked into git under `.claude/commands/` and shared with the team.

```
> /commit-push-pr
```

**Power feature:** Slash commands can include inline Bash to pre-compute info (like git status) for quick execution without extra model calls.

---

## 6. Subagents

### Use Subagents for Common Workflows
Think of subagents as automations for the most common PR workflows:

```
.claude/
  agents/
    build-validator.md
    code-architect.md
    code-simplifier.md
    oncall-guide.md
    verify-app.md
```

**Examples:**
- `code-simplifier` - Cleans up code after Claude finishes
- `verify-app` - Detailed instructions for end-to-end testing

### Leveraging Subagents
- Append "use subagents" to any request where you want Claude to throw more compute at the problem
- Offload individual tasks to subagents to keep your main agent's context window clean and focused
- Route permission requests to Opus 4.5 via a hook - let it scan for attacks and auto-approve the safe ones

---

## 7. Hooks

### PostToolUse Hooks for Formatting
Use a PostToolUse hook to auto-format Claude's code. While Claude generates well-formatted code 90% of the time, the hook catches edge cases to prevent CI failures.

```json
"PostToolUse": [
  {
    "matcher": "Write|Edit",
    "hooks": [
      {
        "type": "command",
        "command": "bun run format || true"
      }
    ]
  }
]
```

### Stop Hooks for Long-Running Tasks
For very long-running tasks, use an agent Stop hook for deterministic checks, ensuring Claude can work uninterrupted.

---

## 8. Permissions

### Pre-Allow Safe Permissions
Instead of `--dangerously-skip-permissions`, use `/permissions` to pre-allow common safe commands. Most are shared in `.claude/settings.json`.

For sandboxed environments, use `--permission-mode=dontAsk` or `--dangerously-skip-permissions` to avoid blocks.

---

## 9. MCP Integrations

### Tool Integrations
Claude Code uses your tools autonomously:
- Searches and posts to **Slack** (via MCP server)
- Runs **BigQuery** queries with bq CLI
- Grabs error logs from **Sentry**

```json
{
  "mcpServers": {
    "slack": {
      "type": "http",
      "url": "https://slack.mcp.anthropic.com/mcp"
    }
  }
}
```

### Data & Analytics
Ask Claude Code to use the "bq" CLI to pull and analyze metrics on the fly. Have a BigQuery skill checked into the codebase.

Boris's take: "Personally, I haven't written a line of SQL in 6+ months."

This works for any database that has a CLI, MCP, or API.

---

## 10. Prompting Tips

### Challenge Claude
- Say "Grill me on these changes and don't make a PR until I pass your test."
- Say "Prove to me this works" and have Claude diff behavior between main and your feature branch

### After a Mediocre Fix
Say: "Knowing everything you know now, scrap this and implement the elegant solution."

### Write Detailed Specs
Reduce ambiguity before handing work off. The more specific you are, the better the output.

**Key insight:** Don't accept the first solution. Push Claude to do better - it usually can.

---

## 11. Terminal Setup

### Recommended Tools
- **Ghostty** terminal - synchronized rendering, 24-bit color, proper unicode support
- Use `/statusline` to customize your status bar to always show context usage and current git branch

### Voice Dictation
Use voice dictation! You speak 3x faster than you type, and your prompts get way more detailed as a result. Hit `fn x2` on macOS.

---

## 12. Bug Fixing

### Let Claude Fix Bugs
Enable the Slack MCP, then paste a Slack bug thread into Claude and just say "fix." Zero context switching required.

Or just say "Go fix the failing CI tests." Don't micromanage how.

**Pro tip:** Point Claude at docker logs to troubleshoot distributed systems - it's surprisingly capable at this.

---

## 13. Long-Running Tasks

### Handle Long-Running Tasks
For very long-running tasks, ensure Claude can work uninterrupted:

**Options:**
- **(a)** Prompt Claude to verify with a background agent when done
- **(b)** Use an agent Stop hook for deterministic checks
- **(c)** Use the "ralph-wiggum" plugin (community idea by @GeoffreyHuntley)

For sandboxed environments, use `--permission-mode=dontAsk` or `--dangerously-skip-permissions` to avoid blocks.

---

## 14. Verification (The #1 Tip)

### Give Claude a Way to Verify Its Work
"Probably the most important thing to get great results out of Claude Code - give Claude a way to verify its work. If Claude has that feedback loop, it will 2-3x the quality of the final result."

**Verification varies by domain:**
- Bash commands
- Test suites
- Simulators
- Browser testing (Claude Chrome extension)

The key is giving Claude a way to close the feedback loop. Invest in domain-specific verification for optimal performance.

---

## 15. Learning with Claude

### Use Claude for Learning
- Enable "Explanatory" or "Learning" output style in /config to have Claude explain the *why* behind changes
- Have Claude generate visual HTML presentations explaining unfamiliar code
- Ask Claude to draw ASCII diagrams of new protocols and codebases
- Build a spaced-repetition learning skill: explain your understanding, Claude asks follow-ups to fill gaps

**Key takeaway:** Claude Code isn't just for writing code - it's a powerful learning tool when you configure it to explain and teach.

---

## 16. Terminal Configuration

### Configure Your Terminal
A few quick settings to make Claude Code feel right:

- **Theme:** Run `/config` to set light/dark mode
- **Notifications:** Enable notifications for iTerm2, or use a custom notifs hook
- **Newlines:** If you use Claude Code in an IDE terminal, Apple Terminal, Warp, or Alacritty, run `/terminal-setup` to enable shift+enter for newlines (so you don't need to type `\`)
- **Vim mode:** Run `/vim`

---

## 17. Effort Level

### Adjust Effort Level
Run `/model` to pick your preferred effort level:

- **Low** — less tokens & faster responses
- **Medium** — balanced behavior
- **High** — more tokens & more intelligence

Boris uses High for everything.

---

## 18. Plugins

### Install Plugins, MCPs, and Skills
Plugins let you install LSPs (now available for every major language), MCPs, skills, agents, and custom hooks.

Install a plugin from the official Anthropic plugin marketplace, or create your own marketplace for your company. Then, check the `settings.json` into your codebase to auto-add the marketplaces for your team.

Run `/plugin` to get started.

---

## 19. Custom Agents

### Create Custom Agents
Drop `.md` files in `.claude/agents`. Each agent can have a custom name, color, tool set, pre-allowed and pre-disallowed tools, permission mode, and model.

**Little-known feature:** Set the default agent used for the main conversation. Just set the `"agent"` field in your `settings.json` or use the `--agent` flag.

Run `/agents` to get started.

---

## 20. Permissions Management

### Pre-Approve Common Permissions
Claude Code uses a sophisticated permission system with prompt injection detection, static analysis, sandboxing, and human oversight.

Out of the box, we pre-approve a small set of safe commands. To pre-approve more, run `/permissions` and add to the allow and block lists. Check these into your team's `settings.json`.

**Wildcard syntax:** We support full wildcard syntax. Try `"Bash(bun run *)"` or `"Edit(/docs/**)"`.

---

## 21. Sandboxing

### Enable Sandboxing
Opt into Claude Code's open source sandbox runtime to improve safety while reducing permission prompts.

Run `/sandbox` to enable it. Sandboxing runs on your machine, and supports both file and network isolation.

**Modes:**
- Sandbox BashTool, with auto-allow
- Sandbox BashTool, with regular permissions
- No Sandbox

---

## 22. Status Line

### Add a Status Line
Custom status lines show up right below the composer. Show model, directory, remaining context, cost, and anything else you want to see while you work.

Everyone on the Claude Code team has a different statusline. Use `/statusline` to get started — Claude will generate one based on your `.bashrc`/`.zshrc`.

---

## 23. Keybindings

### Customize Your Keybindings
Every key binding in Claude Code is customizable. Run `/keybindings` to re-map any key. Settings live reload so you can see how it feels immediately.

Keybindings are stored in `~/.claude/keybindings.json`.

---

## 24. Hooks (Advanced)

### Set Up Hooks
Hooks are a way to deterministically hook into Claude's lifecycle. Use them to:

- Automatically route permission requests to Slack or Opus
- Nudge Claude to keep going when it reaches the end of a turn (you can even kick off an agent or use a prompt to decide whether Claude should keep going)
- Pre-process or post-process tool calls, e.g. to add your own logging

Ask Claude to add a hook to get started.

---

## 25. Spinner Verbs

### Customize Your Spinner Verbs
It's the little things that make CC feel personal. Ask Claude to customize your spinner verbs to add or replace the default list with your own verbs.

Check the `settings.json` into source control to share verbs with your team.

---

## 26. Output Styles

### Use Output Styles
Run `/config` and set an output style to have Claude respond using a different tone or format.

- **Explanatory** — great when getting familiar with a new codebase, to have Claude explain frameworks and code patterns as it works
- **Learning** — have Claude coach you through making code changes
- **Custom** — create your own output styles to adjust Claude's voice the way you like

---

## 27. Customize Everything

### Customize All the Things!
Claude Code is built to work great out of the box. When you do customize, check your `settings.json` into git so your team can benefit, too.

We support configuring for your codebase, for a sub-folder, for just yourself, or via enterprise-wide policies.

**By the numbers:** 37 settings and 84 env vars. Use the `"env"` field in your `settings.json` to avoid wrapper scripts.

---

## 28. Built-in Git Worktree Support

### Use `claude --worktree` for Isolation
Claude Code now has built-in git worktree support. Each agent gets its own worktree and can work independently, without interfering with other sessions.

```bash
# Start Claude in its own worktree
claude --worktree my_worktree

# Optionally launch in its own Tmux session too
claude --worktree my_worktree --tmux
```

**Desktop app:** Head to the Code tab in the Claude Desktop app and check the **worktree** checkbox.

### Subagents Support Worktrees
Subagents can also use worktree isolation to do more work in parallel. This is especially powerful for large batched changes and code migrations. Available in CLI, Desktop app, IDE extensions, web, and Claude Code mobile app.

**Example prompt:** "Migrate all sync io to async. Batch up the changes, and launch 10 parallel agents with worktree isolation. Make sure each agent tests its changes end to end, then have it put up a PR."

### Custom Agents with Worktree Isolation
Make subagents always run in their own worktree by adding `isolation: worktree` to your agent frontmatter:

```yaml
# .claude/agents/worktree-worker.md
---
name: worktree-worker
model: haiku
isolation: worktree
---
```

### Non-Git Source Control
Mercurial, Perforce, or SVN users can define `WorktreeCreate` and `WorktreeRemove` hooks in `settings.json` to benefit from isolation without Git.

---

## 29. /simplify — Improve Code Quality

Use parallel agents to improve code quality, tune code efficiency, and ensure CLAUDE.md compliance. Append `/simplify` to any prompt after making changes.

```
> hey claude make this code change then run /simplify
```

Boris uses this daily to shepherd PRs to production. The skill runs parallel agents that review changed code for reuse, quality, and efficiency — all in one pass.

---

## 30. /batch — Parallel Code Migrations

Interactively plan out code migrations, then execute in parallel using dozens of agents. Each agent runs with full isolation using git worktrees, testing its work before putting up a PR.

```
> /batch migrate src/ from Solid to React
```

You plan the migration interactively, then `/batch` fans out the work to parallel agents — each in its own worktree, each testing and creating a PR independently.

---

## 31. /loop — Schedule Recurring Tasks

Use `/loop` to schedule recurring tasks for up to 3 days at a time. Claude runs your prompt on an interval, handling long-running workflows autonomously.

```
> /loop babysit all my PRs. Auto-fix build issues and when comments come in, use a worktree agent to fix them
```

```
> /loop every morning use the Slack MCP to give me a summary of top posts I was tagged in
```

Use it for PR babysitting, Slack summaries, deploy monitoring, or any repeating workflow.

Learn more: https://code.claude.com/docs/en/scheduled-tasks

## 32. Code Review — Agents Hunt for Bugs

When a PR opens, Claude dispatches a team of agents to hunt for bugs. Anthropic built it for themselves first — code output per engineer is up 200% this year, and reviews were the bottleneck.

Each agent focuses on a different concern — logic errors, security issues, performance regressions — then posts inline comments directly on the PR. Boris personally used it for weeks before launch; it catches real bugs he wouldn't have noticed otherwise.

Source: https://x.com/bcherny/status/2031089411820228645

## 33. /btw — Ask Questions While Claude Works

A slash command for side-chain conversations while Claude is actively working. Single-turn, no tool calls, but has full context of the conversation.

```
> /btw what does the retry logic do?
```

Claude responds inline without stopping its work. Built by @ErikSchluntz as a side project — 1.5M views on the launch tweet.

Source: https://x.com/trq212/status/2031506296697131352

## 34. /effort — Max Reasoning Mode

Set effort to 'max' and Claude reasons for longer, using as many tokens as needed. Burns through usage limits faster, so you activate it per session.

```
> /effort max
```

Four levels: low, medium (default), high, max. Use 'max' for hard debugging, architecture decisions, or tricky code where you want Claude to really think it through.

Source: https://x.com/trq212/status/2032632596572811575

## 35. Remote Control — Spawn New Sessions

Run `claude remote-control` and spawn a new local session from the mobile app. Available on Max, Team, and Enterprise (v2.1.74+).

```bash
$ claude remote-control
# Open Claude mobile app → tap "Code" → start new session
```

Walk away from your desk, think of something, kick off a task from mobile — Claude runs on your machine.

Source: https://x.com/trq212/status/2032632597843779861

## 36. Voice Mode

Voice mode is now rolled out to 100% of users, including Claude Code Desktop and Cowork. Click the microphone icon and talk naturally.

Useful for hands-free coding, dictating complex requirements, or when you think faster than you type.

Source: https://x.com/trq212/status/2032632599429136753

## 37. Setup Scripts for Cloud Environments

Add a setup script in Claude Code on web and desktop. It runs before Claude Code launches on a cloud environment — install dependencies, configure settings, set env vars.

```bash
# Setup script (runs on new session start, skipped on resume):
#!/bin/bash
yarn install
```

Particularly useful for installing dependencies, settings, and configs before Claude starts working.

Source: https://x.com/trq212/status/2032632601064907037

## 38. claude --name — Name Your Sessions

Name your session at launch with the `--name` flag.

```bash
$ claude --name "auth-refactor"
```

Especially useful when juggling multiple worktrees or sessions — you can tell at a glance which session is doing what.

Source: https://x.com/trq212/status/2032632602629386348

## 39. Auto Session Naming After Plan Mode

After plan mode, Claude automatically names your session based on what you're working on. No manual naming needed.

Pairs well with `claude --name` — use `--name` when you know what you're doing upfront, let auto-naming handle it when you start by planning.

Source: https://x.com/trq212/status/2032632602629386348

## 40. /color — Customize Prompt Color

Change the color of the prompt input with `/color`. When you have 3-5 sessions open in different terminals, color-coding them makes it instantly clear which is which.

```
> /color
```

Source: https://x.com/trq212/status/2032632602629386348

## 41. PostCompact Hook

A new hook event that fires after Claude compresses its conversation context. Use it to re-inject critical instructions that might get lost during compaction, log when compaction happens, or trigger automation.

```json
"hooks": {
  "PostCompact": [{
    "matcher": "",
    "hooks": [{ "type": "command", "command": "echo 'Context was compacted'" }]
  }]
}
```

Source: https://x.com/trq212/status/2032632602629386348

## 42. Auto Mode — Safer Permission Skipping

Instead of approving every file write and bash command, or skipping permissions entirely, auto mode lets Claude make permission decisions on your behalf. Classifiers evaluate each action before it runs — safe operations get auto-approved, risky ones still get flagged.

```bash
# Enable auto mode
claude --enable-auto-mode

# Or cycle with shift+tab during a session:
# plan mode → auto mode → normal mode
```

Boris's take: "no 👏 more 👏 permission prompts 👏"

Source: https://x.com/bcherny/status/2036555259997462541

## 43. /schedule — Cloud Jobs from Your Terminal

Use `/schedule` to create recurring cloud-based jobs for Claude, directly from the terminal. Unlike `/loop` (which runs locally for up to 3 days), scheduled jobs run in the cloud — they work even when your laptop is closed.

```
> /schedule a daily job that looks at all PRs shipped since yesterday
  and update our docs based on the changes. Use the Slack MCP to
  message #docs-update with the changes
```

The Anthropic team uses these internally to automatically resolve CI failures, push doc updates, and power automations that need to exist beyond a closed laptop.

Source: https://x.com/noahzweben/status/2036129220959805859

## 44. iMessage Plugin — Text Claude from Your Phone

iMessage is now available as a Claude Code channel. Install the plugin and text Claude like you'd text a friend — from any Apple device.

```bash
/plugin install imessage@claude-plugins-official
```

Claude Code becomes a contact in your Messages app. Send it tasks, get responses as iMessages. Works from your iPhone, iPad, or Mac — no terminal needed. Pairs well with remote control sessions for kicking off work from anywhere.

Source: https://x.com/trq212/status/2036959638646866021

## 45. Auto-Memory & Auto-Dream — Persistent, Self-Cleaning Memory

Claude Code has a built-in memory system. Run `/memory` to configure it.

**Auto-memory:** When enabled, Claude automatically saves preferences, corrections, and patterns between sessions. User memory goes to `~/.claude/CLAUDE.md`, project memory to `./CLAUDE.md`.

**Auto-dream:** As memory accumulates, it can get messy — outdated assumptions, overlapping notes, low-signal entries. Auto-dream runs a subagent that periodically reviews past sessions, keeps what matters, removes what doesn't, and merges insights into cleaner structured memory. Run `/dream` to trigger manually, or enable auto-dream in `/memory` settings.

The naming maps to how REM sleep consolidates short-term memory into long-term storage.

## 46. Mobile App — Code from Your Phone

Claude Code has a mobile app. Download the Claude app for iOS/Android, then tap the Code tab on the left. Boris writes a lot of his code from the iOS app — it's a convenient way to make changes without opening a laptop.

Source: https://x.com/bcherny/status/2038454337811386436

## 47. Session Teleporting — Move Between Devices

Move sessions back and forth between mobile/web/desktop and terminal.

```bash
# Continue a cloud session on your machine
claude --teleport
# or /teleport from inside a session

# Control a local session from phone/web
/remote-control
```

Boris has "Enable Remote Control for all sessions" set in his /config.

Source: https://x.com/bcherny/status/2038454339933548804

## 48. /loop and /schedule — Automated Workflows

Two of the most powerful features in Claude Code. Use these to schedule Claude to run automatically at a set interval, for up to a week at a time.

Boris's running loops:
- `/loop 5m /babysit` — auto-address code review, auto-rebase, and shepherd PRs to production
- `/loop 30m /slack-feedback` — automatically put up PRs for Slack feedback every 30 mins
- `/loop /post-merge-sweeper` — put up PRs to address code review comments I missed
- `/loop 1h /pr-pruner` — close out stale and no longer necessary PRs

**Pro tip:** Experiment with turning workflows into skills + loops. It's powerful.

Source: https://x.com/bcherny/status/2038454341884154269

## 49. Hooks — Deterministic Agent Lifecycle Logic

Use hooks to deterministically run logic as part of the agent lifecycle:
- Dynamically load in context each time you start Claude (SessionStart)
- Log every bash command the model runs (PreToolUse)
- Route permission prompts to WhatsApp for you to approve/deny (PermissionRequest)
- Poke Claude to keep going whenever it stops (Stop)

See https://code.claude.com/docs/en/hooks

Source: https://x.com/bcherny/status/2038454343519932844

## 50. Cowork Dispatch — Remote Control for Claude Desktop

Boris uses Dispatch every day to catch up on Slack and emails, manage files, and do things on his laptop when he's not at a computer. "When I'm not coding, I'm dispatching."

Dispatch is a secure remote control for the Claude Desktop app. It can use your MCPs, browser, and computer, with your permission.

Source: https://x.com/bcherny/status/2038454345419936040

## 51. Chrome Extension — Verify Frontend Work

The most important tip for using Claude Code: give Claude a way to verify its output. Once you do that, Claude will iterate until the result is great.

Think of it like any other engineer: if you ask someone to build a website but they aren't allowed to use a browser, will the result look good? Probably not. But if you give them a browser, they will write code and iterate until it looks good.

Boris uses the Chrome extension every time he works on web code. It tends to work more reliably than other similar MCPs. Download for Chrome/Edge at code.claude.com/docs/en/browser.

Better than Playwright or a Chromium MCP for E2E? Asked directly, Boris: "Yes. It's more powerful and more token-efficient." For a long autonomous run, hand verification to a workflow: *"use a workflow to test the result e2e in a browser using claude in chrome mcp. Especially look for edge cases and ui issues."* (Boris's June 2026 "running Opus autonomously" thread.)

Source: https://x.com/bcherny/status/2038454347156398333
Source: https://x.com/bcherny/status/2063792263067754658

## 52. Desktop App — Auto Start and Test Web Servers

Use the Claude Desktop app to have Claude automatically start and test web servers. The Desktop app bundles in the ability for Claude to automatically run your web server and even test it in a built-in browser.

You can set up something similar in CLI or VSCode using the Chrome extension, or just use the Desktop app.

Source: https://x.com/bcherny/status/2038454348804714642

## 53. Fork Your Session

People often ask how to fork an existing session. Two ways:

```bash
# Option 1: From inside your session
/branch

# Option 2: From the CLI
claude --resume <session-id> --fork-session
```

Source: https://x.com/bcherny/status/2038454350214041740

## 54. /btw — Side Queries While Claude Works

Use /btw all the time to answer quick questions while the agent works. Single-turn, no tool calls, but has full context of the conversation. Claude responds inline without stopping its work.

```
> /btw how do i spell daushund?
  dachshund — German for "badger dog" (dachs = badger, hund = dog).
```

Source: https://x.com/bcherny/status/2038454351849787485

## 55. Git Worktrees — Deep Parallel Work

Claude Code ships with deep support for git worktrees. Worktrees are essential for doing lots of parallel work in the same repository. Boris has dozens of Claudes running at all times.

```bash
# Start a new session in a worktree
claude -w

# Or check the "worktree" checkbox in the Claude Desktop app
```

For non-git VCS users, use the WorktreeCreate hook to add your own logic for worktree creation.

Source: https://x.com/bcherny/status/2038454353787519164

## 56. /batch — Fan Out Massive Changesets

/batch interviews you, then has Claude fan out the work to as many worktree agents as it takes (dozens, hundreds, even thousands) to get it done. Use it for large code migrations and other kinds of parallelizable work.

Source: https://x.com/bcherny/status/2038454355469484142

## 57. --bare — 10x Faster SDK Startup

By default, when you run `claude -p` (or the TypeScript or Python SDKs) it searches for local CLAUDE.md's, settings, and MCPs. But for non-interactive usage, most of the time you want to explicitly specify what to load via --system-prompt, --mcp-config, --settings, etc.

```bash
claude -p "summarize this codebase" \
    --output-format=stream-json \
    --verbose \
    --bare
```

This was a design oversight when the SDK was first built. In a future version, the default will flip to --bare. For now, opt in with the flag.

Source: https://x.com/bcherny/status/2038454357088457168

## 58. --add-dir — Give Claude Access to More Folders

When working across multiple repositories, start Claude in one repo and use `--add-dir` (or `/add-dir`) to let Claude see the other repo. This not only tells Claude about the repo, but also gives it permissions to work in it.

```bash
# At launch
claude --add-dir /path/to/other-repo

# During a session
> /add-dir /path/to/other-repo
```

Or, add "additionalDirectories" to your team's settings.json to always load in additional folders when starting Claude Code.

Source: https://x.com/bcherny/status/2038454359047156203

## 59. --agent — Custom System Prompt & Tools

Custom agents are a powerful primitive that often gets overlooked. Define a new agent in .claude/agents, then run `claude --agent=<your agent's name>`.

```yaml
# .claude/agents/ReadOnly.md
---
name: ReadOnly
description: Read-only agent restricted to the Read tool only
color: blue
tools: Read
---

You are a read-only agent that cannot edit files or run bash.
```

See https://code.claude.com/docs/en/sub-agents

Source: https://x.com/bcherny/status/2038454360418787764

## 60. /voice — Voice Input

Boris does most of his coding by speaking to Claude, rather than typing. To do the same:
- CLI: run /voice then hold the space bar
- Desktop: press the voice button
- iOS: enable dictation in your iOS settings

Source: https://x.com/bcherny/status/2038454362226467112

---

## 61. Routines — Scheduled & Event-Driven Claude Code

Configure a routine once (prompt, repo, connectors), and it runs on a schedule, from an API call, or in response to a GitHub event. Runs on Anthropic infrastructure — no laptop required.

Triggers:
- **Schedule** — cron expression
- **GitHub event** — PR opened/merged, release published, issue opened
- **API** — POST to a webhook URL with token

Connectors: GitHub, Linear. Each routine has its own API endpoint, so you can point alerts, deploy hooks, or internal tools at Claude directly.

Use cases: POST an oncall alert payload to the routine's webhook, Claude finds the owning service and posts a triage summary. PR quality checks on opened PRs. Release notes on release-published events.

Research preview announced Apr 14, 2026.

Source: https://x.com/claudeai/status/2044095086460309790

## 62. Rewind Over Correcting

The single habit that signals good context management is rewind, not correction.

When Claude goes down a wrong path, don't type "that didn't work, try X instead." That keeps the failed attempt in context and pollutes the window. Instead:
- Double-tap Esc (or run `/rewind`)
- Jumps back to a previous message, drops everything after it
- Re-prompt with what you learned: "use approach C, not A/B"

The math:
- Correcting: context = file reads + failed attempt + correction + fix
- Rewinding: context = file reads + one informed prompt + fix

Also: use `"summarize from here"` to have Claude summarize its learnings into a handoff message before rewinding — a note from the next iteration of Claude to its past self.

Source: https://x.com/trq212/status/2044548257058328723

## 63. /compact vs /clear — Know the Difference

Two ways to shed weight from a long session. They feel similar but behave very differently.

**/compact — lossy LLM summary:**
- Claude summarizes the conversation and replaces the history with the summary
- Cheap, keeps momentum, details can be fuzzy
- You're trusting Claude to decide what mattered
- Steer it with a hint: `/compact focus on the auth refactor, drop the test debugging`

**/clear — hand-written brief:**
- You write down what matters ("we're refactoring the auth middleware, constraint is X, files are A and B, we've ruled out approach Y")
- Precise. You decide what carries forward
- More work, but the context is exactly what you chose

Rule of thumb: starting a genuinely new task → `/clear`. Related task where you still need some context → `/compact` with a hint.

Bad compact warning: autocompact fires mid-task and can summarize the wrong things (e.g. finishes summarizing a debugging thread right before you ask about a different warning it glossed over). Proactive `/compact <hint>` avoids this.

Source: https://x.com/trq212/status/2044548257058328723

## 64. Lower Your Auto-Compact Threshold

Context rot — model performance degrading as context grows — kicks in around 300-400k tokens on the 1M context model. You can set your autocompact threshold to force earlier compaction and effectively lower your context window.

```bash
# 400k is Thariq's recommended compromise
CLAUDE_CODE_AUTO_COMPACT_WINDOW=400000 claude
```

Why this works: stays below the rot zone while still getting most of the 1M benefit. Context windows are a hard cutoff — when you near the end, you're forced to compact. Forcing it earlier means your compaction happens while the model is still sharp.

Pair with proactive `/compact <hint>` when you feel bad-compact risk.

Docs: https://docs.claude.com/en/docs/claude-code/settings
Source: https://x.com/trq212/status/2044548257058328723

## 65. Delegation over Guidance (Opus 4.7)

Mental model shift from Cat Wu (Apr 16, 2026) on Opus 4.7 in Claude Code:

> "The model performs best if you treat it like an engineer you're delegating to, not a pair programmer you're guiding line by line."

**Old workflow:** describe step, watch output, correct, describe next step. High interrupt frequency. You're always in the loop.

**New workflow:** write a crisp brief, launch Claude, come back when it's done (or when it asks a real question). Fewer interruptions, more autonomous runs, higher quality output.

When Claude asks too many clarifying questions or goes off-track, that's usually a signal that your brief was incomplete — not that the model needs more hand-holding. Invest in the upfront brief (see tip 66) and let Opus 4.7 do its thing.

Source: https://x.com/_catwu/status/2044808533905178822

## 66. Full Task Context Upfront

The delegation model (tip 65) only works if Claude has what it needs. Cat's second tip:

> "Give Claude Code your full task context upfront: goal, constraints, acceptance criteria in the first turn."

The three things to include:
- **Goal** — what success looks like in plain language
- **Constraints** — non-goals, things not to touch, perf/API contracts
- **Acceptance criteria** — how you'll verify the work is done right

Example:
```
Goal: add rate limiting to the /api/login endpoint

Constraints:
- don't modify the DB schema
- keep the existing auth flow unchanged
- use Redis (already configured)

Acceptance criteria:
- 5 req/min per IP, returns 429 on limit
- existing tests still pass
- new test case for the rate-limit behavior
```

If Claude starts with all three, it plans around the full problem space. If it starts with just "add rate limiting," it'll make assumptions you'll have to correct later — and every correction costs context.

Source: https://x.com/_catwu/status/2044808533905178822

## 67. xhigh — New Default Effort for Opus 4.7

Opus 4.7 in Claude Code defaults to `xhigh` — a new effort level beyond the low/medium/high/max scale tip 34 described. The model reasons longer before acting, which pairs with the delegation shift: think harder once, rather than iterate fast and bounce back to you.

```bash
# check or change the effort level
$ /effort
```

**Why xhigh is the new default:** xhigh effort + a full-context brief = one-shot completion of bigger tasks than previous Opus models could handle. The default change signals that Opus 4.7 is expected to run more autonomously, which benefits from more reasoning tokens upfront.

Drop it down if you want speed over depth, or leave it alone for most work. Available through `/effort` just like the other levels.

Source: https://x.com/_catwu/status/2044808533905178822

## 68. Auto Mode + Parallel Claudes (Opus 4.7)

Opus 4.7 loves complex, long-running tasks — deep research, refactoring code, building complex features, iterating until it hits a performance benchmark. In the past, you had to babysit permission prompts or use --dangerously-skip-permissions.

Auto mode routes permission prompts to a model-based classifier. Safe = auto-approved. No more babysitting.

**The real unlock:** it means you can run more Claudes in parallel. Once a Claude is cooking, switch focus to the next one. Auto mode + worktrees = a fleet of autonomous Claudes, each on its own task.

Shift-tab in the CLI, dropdown in Desktop or VSCode. Available for Max, Teams, Enterprise.

Source: https://x.com/bcherny/status/2044847849662505288

## 69. /fewer-permission-prompts — Tune Your Allowlist

A new skill that scans through your session history to find common bash and MCP commands that are safe but caused repeated permission prompts. It recommends a list of commands to add to your permissions allowlist.

```bash
/fewer-permission-prompts
```

Use this to tune up your permissions and avoid unnecessary prompts, especially if you don't use auto mode.

Source: https://x.com/bcherny/status/2044847851591856461

## 70. Recaps — Know What Happened While You Were Away

Shipped alongside Opus 4.7. Recaps are short summaries of what an agent did and what's next. Very useful when returning to a long-running session after a few minutes or a few hours.

Example:
```
recap: Fixing the post-submit transcript shift bug.
The styling-flash part is shipped as PR #29869 (auto-merge on).
Next: I need a screen recording of the remaining horizontal rewrap
on cc -c to target that separate cause.
```

Pairs naturally with auto mode — you launch Claude, switch focus, come back, and immediately see what happened. Disable in `/config`.

Source: https://x.com/bcherny/status/2044847853030580247

## 71. Focus Mode — See Only the Final Result

Boris: "I've been loving the new focus mode in the CLI, which hides all the intermediate work to just focus on the final result. The model has reached a point where I generally trust it to run the right commands and make the right edits. I just look at the final result."

```bash
/focus
```

Toggle on/off. A natural complement to auto mode — one removes permission prompts, the other removes visual clutter.

Source: https://x.com/bcherny/status/2044847855006024147

## 72. Effort Mastery — xhigh, max, and Adaptive Thinking

Opus 4.7 uses adaptive thinking instead of fixed thinking budgets. The model decides when thinking is beneficial — less overthinking, smarter resource use.

Boris's setup: "I use xhigh effort for most tasks, and max effort for the hardest tasks."

The effort scale: low → medium → high → xhigh → max (Speed ← → Intelligence)

**Key detail:** Max applies to just your current session. All other effort levels (including xhigh) are sticky and persist for your next session too.

To steer thinking without changing effort level:
- Harder problems: "Think carefully and step-by-step before responding; this problem is harder than it looks."
- Save tokens: "Prioritize responding quickly rather than thinking deeply. When in doubt, respond directly."

`/effort` to set your level.

Source: https://x.com/bcherny/status/2044847856872546639

## 73. /go — Verify, Simplify, Ship

"Give Claude a way to verify its work. This has always been a way to 2-3x what you get out of Claude, and with 4.7 it's more important than ever."

Boris's workflow: "Many of my prompts look like 'Claude do blah blah /go'."

`/go` is a skill that has Claude:
1. Test itself end to end using bash, browser, or computer use
2. Run the /simplify skill
3. Put up a PR

Verification by domain: backend → start your server/service end-to-end; frontend → Claude Chromium extension; mobile → iOS/Android simulator MCP; desktop apps → computer use.

Scripted or Claude-driven tests? Asked whether tests should be scripted (guaranteed but flaky) or Claude-driven, Boris: "We do both! Depends if it's a one-off or something you want to run on future PRs." One-off check → let Claude drive it; something you want to re-run on every PR → have it write a real test.

"For long running work, verification is important because that way when you come back to a task, you know the code works."

Source: https://x.com/bcherny/status/2044847858634064115
Source: https://x.com/bcherny/status/2063792263067754658

## 74. What Changed from 4.6 — Three Behavioral Shifts

If you're upgrading from 4.6, three changes matter. Don't assume old habits carry over.

**1. Calibrated response length.** Shorter answers for simple queries, longer for open-ended analysis. If you want a specific length or style, say so explicitly.

**2. Less automatic tool usage.** 4.7 reasons more instead of immediately calling tools. Provide explicit guidance describing when and why to use tools if Claude isn't reaching for the right ones.

**3. More judicious subagent spawning.** 4.7 doesn't fan out on its own as much. For "refactor across 40 files" tasks, explicitly request parallel subagents. Anti-pattern: don't spawn subagents for refactoring a single visible function.

Source: https://claude.com/blog/best-practices-for-using-claude-opus-4-7-with-claude-code

## 75. Task Completion Notifications

With auto mode + focus mode, you spend less time watching Claude work. Set up notifications so you know when it finishes:

- **Sound alert** — ask Claude to play a sound when done
- **Stop hook** — trigger a Slack message, system notification, or custom action
- **iTerm2 notifications** — native terminal alerts
- **Recaps** — when you do check back, recaps tell you what happened (see tip 70)

The full Opus 4.7 workflow: start Claude in auto mode with focus on. It runs autonomously, verifies via `/go`, and notifies you when done. You review the recap and the PR.

Source: https://claude.com/blog/best-practices-for-using-claude-opus-4-7-with-claude-code

---

## 76. Agent View — One List of All Your Sessions

Native control plane for managing multiple Claude Code sessions. Shipped May 11, 2026 as a research preview. Run `claude agents` from a root code directory; it tracks every session under that root and groups them by **needs input**, **working**, **completed**.

```bash
# launch the control plane from your root code dir
claude agents

# from any cli session, hit <- to register it with the control plane
```

**Setup pattern (Thariq, Cat Wu):** start `claude agents` in a high-level directory containing all your repos. Thariq uses `~/Projects`. Every session launched under that root gets tracked.

**Operational tips (Dickson Tsai):**
- New sessions inherit the directory your cursor is on — start a session in any repo in one keystroke
- Renaming is critical for keeping the view scannable as sessions pile up. Use `/rename` or set up a `UserPromptSubmit` hook to auto-rename

**Why this matters:** this is the productized version of Tip 1 (parallel execution via worktrees). Same productivity goal — many concurrent sessions — but with first-class tooling instead of manual terminal tabs and `za`/`zb`/`zc` aliases.

Boris's framing: *"The best way to level up from 1 agent => many agents. No more cycling between terminal tabs."* Thariq: *"kind of like tmux built for CC."*

Sources:
- https://x.com/bcherny/status/2053982327123132846
- https://x.com/trq212/status/2053979505346425179
- https://x.com/_catwu/status/2053999857799672111
- https://x.com/dickson_tsai/status/2054008483402694807

---

## 77. /goal — Keep Claude Working Until the Condition Is Met

Surfaced in a @ClaudeDevs thread on May 12, 2026, described as "shipped recently" (exact ship date pending changelog confirmation). `/goal` sets a completion condition. Claude keeps working until the condition is true. Every time it tries to stop, the model checks the condition against the transcript. Not done, it keeps going. Done, you get a "Goal achieved" summary.

```bash
# set a completion condition
/goal all tests in test/auth pass and the lint step is clean
```

**How it works:** ClaudeDevs calls this the **Ralph loop, built into Claude Code**. Each stop attempt is intercepted; the model self-checks against your condition before exiting. The loop only breaks when the condition is satisfied.

**Companion tools (already in this skill):**
- `/loop` (tip 31, 48) — runs Claude on repeat. Good for iterative refactors, cleanups, burning down a backlog.
- `/schedule` (tip 43, 48) — kicks off Claude on a cadence. Nightly test runs, morning triage, weekly cleanup.
- `Stop` hook (tip 7, 13, 24) — programmatic control over when Claude can finish. Run your test suite, hit a CI endpoint, gate on anything.
- Auto mode (tip 42, 68) — lets Claude work uninterrupted without permission prompts. Enable with shift+tab in CLI or via the mode selector on desktop.

**Pairs with Part 12 Tip 76 (Agent View):** agent view lets you run many sessions at once; `/goal` makes each session finish what it started. Worktrees (tip 1) + auto mode (tip 68) + `/goal` approximates an autonomous fleet that doesn't need babysitting.

Docs: "Keep Claude working toward a goal" at code.claude.com.

Source: https://x.com/ClaudeDevs/status/2054351031279186040

---

## 78. Opus 4.8 — Strongest Coding Model Yet

Anthropic shipped **Claude Opus 4.8** on May 28, 2026. Boris's framing: *"It's our strongest coding model yet: up on SWE-bench Pro (from 64.3 to 69.2) and noticeably more honest about its own work. It tells you when it's unsure and catches its own bugs instead of declaring victory early. Same price as 4.7."*

> **Superseded (June 9, 2026):** **Claude Fable 5** is now the strongest coding model — Boris calls it the best he's used for coding "by a wide margin" (Section 94). The Opus 4.8 details below remain accurate for that release; Fable 5 now leads.

**Benchmark deltas vs 4.7:**
- Agentic coding (SWE-Bench Pro): 64.3% → **69.2%**
- Agentic terminal coding (Terminal-Bench 2.1): 66.1% → **74.6%**
- Multidisciplinary reasoning (Humanity's Last Exam, with tools): 54.7% → **57.9%**
- Agentic computer use (OSWorld-Verified): 82.8% → **83.4%**
- Knowledge work (GDPval-AA): 1753 → **1890**
- Agentic financial analysis (Finance Agent v2): 51.5% → **53.9%**

**Why the honesty shift matters more than the benchmarks:** A model that overclaims at step 4 wastes the next 40 steps. Pair this with `/goal` (tip 77) and dynamic workflows (tip 80): honesty is what makes async work actually finish.

**Also shipped today:**
- **Fast mode for Opus 4.8** (research preview): same model at roughly 2.5x the speed, 3x cheaper than before. Toggle with `/fast` in Claude Code.
- **New effort control on claude.ai**: choose how much thinking Claude puts into each response — the consumer surface catching up to what Claude Code users already had.

Live on claude.ai, the Claude Platform, and all major cloud platforms.

Source: https://x.com/bcherny/status/2060048873440129073

---

## 79. High-Effort Default + xhigh + Raised Rate Limits

Boris on the effort change for Opus 4.8: *"4.8 defaults to high effort, which spends about the same tokens as 4.7's default on coding but performs better. For hard problems and long-running async work, switch to xhigh. We've raised Claude Code rate limits to cover the extra tokens."*

```bash
# default — same tokens as 4.7's default, better output
/effort high

# hard problems, async runs, dynamic workflows
/effort xhigh
```

**Carry-over from Part 11:** Part 11 introduced `xhigh` as Opus 4.7's new top tier (tip 72: Effort Mastery). With 4.8, the *default* moved up — what used to be a deliberate choice is now baseline. Mental model: assume more reasoning per turn, and reach for `xhigh` when you'd previously have reached for "let it think longer."

**When the extra tokens pay off:** Boris ties `xhigh` directly to dynamic workflows (tip 80) and long-running async runs. Short conversational tasks don't need it — the default is already higher than 4.7's. Save `xhigh` for jobs where you're not watching the screen.

**Rate limits raised:** Anthropic raised Claude Code rate limits alongside the launch specifically to cover the extra reasoning tokens. No quota panic for routine use.

Source: https://x.com/bcherny/status/2060048875918930045

---

## 80. Dynamic Workflows — Days or Weeks Instead of Quarters

Research preview shipped May 28, 2026 alongside Opus 4.8. Boris: *"We also shipped dynamic workflows in Claude Code (research preview), for tasks too big for one pass. Make sure to default to auto mode so Claude isn't stopping for permissions."*

**How to invoke it.** Cat Wu: *"Mention 'workflow' in a prompt and Claude will dynamically create an orchestration plan that it strictly follows, allowing you to confidently trust that every stage happens in the right order even across 100s of agents."* Claude takes a request for a workflow as a signal to plan and execute as a dynamic workflow rather than a single run. No new command, no flag. **Update (June 9, 2026):** Boris refined the trigger to the phrase *"use a workflow"* — the bare word *"workflow"* had too many false positives (see Section 93).

**Under the hood — the orchestrator pattern.** A dynamic workflow is an **orchestrator** shape, not peer-to-peer "agent teams." A top-level `claude` kicks off N tasks (N can be in the 100s). Each task fans out: **implementer** writes, branches into **two verifiers**, both verifiers feed into a single **fixer**. Each task's loop runs until its verifiers pass; the orchestrator returns only once every branch completes. Cat's diagram contrasts this with peer-to-peer "agent teams" — flat collaboration without the strict ordering guarantee:

![Diagram by Cat Wu contrasting peer-to-peer Agent Teams with the Dynamic Workflows orchestrator pattern](https://howborisusesclaudecode.com/live-images/cat-dynamic-workflows.jpeg)

**A concrete example.** Cat: *"Recently, I used dynamic workflows to catalogue all of our 100s of A/B test flags and find the ones rolled out to 0% or 100% so that we can quickly deprecate the stale ones. Instead of waiting for Claude Code to investigate each sequentially, dynamic workflows allowed Claude to process all of them in parallel in <10 minutes."* The pattern's sweet spot: large fan-out across independent items where each needs the same investigation loop.

**Save it for your biggest jobs.** Boris's explicit list plus the category Cat's example highlights:
- Migrations
- Refactors
- Perf optimization
- Batch bug fixes
- Catalogue-and-categorize sweeps across many items (A/B flags, feature toggles, dependencies, dead code, stale endpoints)

It's **token-intensive**. Don't burn it on a 20-line tweak — that's what default mode and the new high-effort baseline (tip 79) are already for.

**Auto mode is not optional.** With hundreds of parallel subagents, a single permission prompt freezes the run. Boris: *"default to auto mode so Claude isn't stopping for permissions."* Shift+tab into auto mode in the CLI, or toggle it on the desktop app. The combo: auto mode (tip 42, 68) + dynamic workflows + `xhigh` (tip 79) = Claude actually walking off and finishing.

**The framing that matters.** Boris: *"Big migrations and refactors are some of a team's most important work, and the easiest to push off to a 'better time' since they'd tie up engineers for a quarter. With dynamic workflows, Claude can now land that kind of work in days or weeks."* The pitch isn't speed for routine work — it's making the kind of work teams perpetually defer actually shippable.

**Pairs with the autonomous fleet from Parts 11–12:** auto mode (tip 68) + agent view (tip 76) + `/goal` (tip 77) + dynamic workflows (tip 80) = the four pillars of work that finishes without you babysitting it.

Sources:
- https://x.com/bcherny/status/2060048877944778995
- https://x.com/bcherny/status/2060048879274414090
- https://x.com/_catwu/status/2060054180379689074
- https://x.com/_catwu/status/2060054182447448387

---

## 81. Why Workflows — Three Failure Modes They Fix

The deep-dive from Thariq Shihipar (@trq212) and Sid Bidasaria (@sidbid), the engineers who built dynamic workflows, published June 2026 (also on the Claude Blog). *"Claude can now write its own harness on the fly, custom-built for the task at hand."*

The default Claude Code harness plans **and** executes in one context window. For most coding that's effective, but the longer Claude works in a single window on a complex, parallel, or adversarial task, the more three failure modes creep in:

- **Agentic laziness** — Claude stops before finishing and declares the job done after partial progress (addressing 20 of 50 items in a security review).
- **Self-preferential bias** — Claude prefers its own results, especially when asked to verify or judge its work against a rubric.
- **Goal drift** — gradual loss of fidelity to the original objective across many turns, worst after compaction. Each summarization is lossy, and "don't do X" constraints quietly fall out.

**The fix:** a workflow orchestrates separate Claudes, each with its own context window and a focused, isolated goal. Laziness loses to a deterministic loop that won't exit until every item is handled; bias loses to a *different* agent doing the judging; drift loses because each agent holds one small goal that never gets summarized away. Ties directly to Part 13's honesty story — a model that overclaims at step 4 wastes the next 40.

Source: https://x.com/trq212/status/2061907337154367865

---

## 82. Workflow Primitives — and Dynamic vs Static

A dynamic workflow is a **JavaScript file** with a few special functions that spawn and coordinate subagents (standard `JSON`, `Math`, `Array` are available for processing data):

- `agent(prompt, opts?)` → `Promise<string | JSON>`. Options: `schema` (a JSON Schema → validated JSON back), `model` (opus · sonnet · haiku · omit = inherit), `isolation: "worktree"` (own checkout for parallel edits), `agentType` (custom or built-in subagent).
- `parallel([ fns ])` — fan out, run at once. A **barrier**: waits for all, then you have every result together.
- `pipeline(items, ...stages)` — each item streams through every stage independently. **No barrier**: item A can be in stage 3 while item B is still in stage 1.

Claude decides which model each agent uses and whether it runs in its own worktree — picking the intelligence and isolation the step needs. Workflows are **resumable**: interrupt one (quit the terminal) and resuming the session picks up where it left off.

**Dynamic vs static.** You may have built *static* workflows with the Agent SDK or `claude -p`. Because static workflows must handle every edge case, they end up generic ("5 web searches → fetch → verify → summarize → a generic report"). With Opus 4.8, Claude is smart enough to write a custom harness tailor-made for your case ("read our billing code → check each feature against the new provider's docs → devil's-advocate the case against migrating → a specific recommendation").

Source: https://x.com/trq212/status/2061907337154367865

---

## 83. The Six Workflow Patterns Claude Composes

Building a mental model for these helps you nudge Claude via prompts. They're not exclusive — Claude mixes and nests them:

1. **Classify-and-act** — a classifier agent decides the task type, then routes to different agents or behavior. Or classify at the end to shape output.
2. **Fan-out-and-synthesize** — split into many steps, run an agent on each, then synthesize. The synthesize step is a **barrier** that waits for all fan-out agents, then merges their structured outputs. Best when each step benefits from its own clean context.
3. **Adversarial verification** — for each spawned agent, a *separate* agent verifies its output against a rubric. The verifier is never the author — this is what kills self-preferential bias.
4. **Generate-and-filter** — generate many ideas, filter by rubric or verification, dedupe, return only the highest-quality tested few.
5. **Tournament** — instead of dividing work, agents **compete**. Spawn N agents that each attempt the task differently, then judge pairwise until a winner. Comparative judgment beats absolute scoring.
6. **Loop-until-done** — for an unknown amount of work, keep spawning agents until a stop condition (no new findings, no more errors) instead of a fixed number of passes.

Source: https://x.com/trq212/status/2061907337154367865

---

## 84. Workflow Use Cases — Often Better for Non-Coding Work

Thariq: *"I've found that workflows are sometimes even more useful for non-technical work."*

- **Migrations & refactors** — Bun was rewritten from Zig to Rust using workflows. Break into units (callsites, failing tests, modules), spin off a subagent per fix in its own worktree, adversarially review, merge. Tell agents to avoid resource-intensive commands so you can maximally parallelize.
- **Deep research & verification** — the `/deep-research` skill *is* a workflow (fan out searches → fetch → adversarially verify → synthesize cited report). The inverse, deep verification: one agent extracts every factual claim, a subagent checks each, an optional source-auditor agent confirms quality. *"Verify every technical claim in my blog draft against the codebase."*
- **Sorting 1,000+ items** — won't fit in one prompt. Run a tournament, a pipeline of pairwise-comparison agents, or bucket-rank in parallel then merge. Each comparison is its own agent; the deterministic loop holds the bracket.
- **Memory & rule adherence** — one verifier agent per rule, plus a skeptic persona to cut false positives. Reverse: mine recent sessions and review comments for recurring corrections, cluster, verify ("would this rule have prevented a real mistake?"), distill survivors into CLAUDE.md.
- **Root-cause investigation** — generate independent hypotheses from disjoint evidence (logs, files, data); each faces verifiers and refuters. Works for sales, data engineering, any post-mortem.
- **Triage, taste, evals, routing** — classify each backlog item, dedupe against tracked, fix or escalate (use a *quarantine* pattern so agents reading untrusted content can't take high-privilege actions; pair with `/loop`). Give a review agent a rubric for design/naming taste. Grade eval outputs in worktrees. Route to Sonnet vs Opus with a classifier.

Source: https://x.com/trq212/status/2061907337154367865

---

## 85. Pair Workflows with /goal, /loop, and Token Budgets

- **/goal + /loop** — for repeatable workflows (triage, research, verification), pair with `/loop` to run at intervals and `/goal` to set a hard completion requirement. Closes the Part 12 + 13 arc: `/goal` sets the exit condition, the workflow does the parallel work, `/loop` keeps it going.
- **Token budgets** — workflows are token-hungry; cap them by prompting a budget directly: *"use 10k tokens."*
- **See what's burning tokens (`/usage`)** — when a long autonomous run eats your limits faster than expected, run `/usage` for a breakdown of the specific skills, MCPs, and plugins spending your tokens. Boris points people here first when they hit limits mid-run.
- **Quick workflows** — not only for big jobs. Prompt a *"quick workflow"* for something small, like a fast adversarial review of a single assumption.
- **When not to use one** — Thariq: *"For regular coding tasks, ask yourself: does it really need more compute? Most traditional coding tasks do not need a panel of 5 reviewers."* Use them to push Claude in new ways, not as the default for a 20-line change.

Source: https://x.com/trq212/status/2061907337154367865
Source: https://x.com/bcherny/status/2063792263067754658

---

## 86. Saving and Sharing Workflows

- **Save** — press **"s"** in the workflow menu. Check the files into `~/.claude/workflows`, or distribute them via a skill.
- **Share via a skill** — put your JavaScript workflow files in the skill folder and reference them in the `SKILL.md`. For flexibility, prompt Claude to treat the workflows as a **template**, not a verbatim script — so it adapts the harness to the case instead of replaying it.
- **The "ultracode" trigger** — start a workflow by asking for one, or use the trigger word **"ultracode"** to guarantee Claude Code builds a workflow rather than a single pass.

Research preview — best practices are still developing. With Part 11's auto mode, Part 12's agent view + `/goal`, and Part 13's Opus 4.8 + workflow launch, this is the fourth pillar of work that finishes without you babysitting it.

Source: https://x.com/trq212/status/2061907337154367865

---

## 87. Auto Mode Retired Plan Mode (Opus 4.6+)

For over a year, Boris's go-to for synchronous coding was plan mode. A year after GA, he's moved on: *"What it used to be is plan mode. I don't use that anymore. I use auto mode — instead of plan mode. The newer models don't actually need a planning step. It was really important for Opus 4 through 4.5, but starting with 4.6, and definitely with 4.7, it just doesn't need it."*

- **Why it changed** — older models needed an explicit plan to stay on track; 4.6+ plan implicitly. The planning step became overhead.
- **What he does instead** — start Claude in auto mode, let it work, move to the next Claude. No artifact to review before work begins, no babysitting.
- **When plan mode still earns its place** — some people keep it for the written artifact (a record of intent), and that's fine. Boris just doesn't, and runs auto mode for everything.

The rule of thumb shifted with the model: pre-4.6, plan first; 4.6 and later, let it run. **This updates Section 3 (Plan Mode)** — pairs with Sections 42 and 68 (Auto Mode).

Source: https://www.youtube.com/watch?v=Hth_tLaC2j8
Source: https://x.com/bcherny/status/2064034799711588805

---

## 88. Context Minimalism — Tell the Model Less

"From context engineering to context minimalism" is its own chapter in the interview. The progression both Boris and Cat draw: Sonnet 3.5 was the era of *prompt engineering*; Opus 4 was the era of *context engineering*; today's models need neither.

Boris: *"You give it the minimal possible system prompt, the minimal possible tools, and then you let the model figure it out. You just have to give the model some way to pull in the context."*

Cat: *"I'm a context minimalist. Tell the model only what it needs to know and let it figure out the rest. When you give the model too much context, it's kind of like you're micromanaging it — and sometimes the model knows a better way to get to the same outcome."*

- **The practical move** — stop front-loading giant prompts and tool lists. Give a lean brief plus a *way to fetch* context (files, search, MCP), then get out of the way.
- **Why** — over-specifying boxes the model into your path and can miss a better one.

Pairs with Section 65 (Delegation over Guidance) and Section 66 (Full Task Context Upfront) — minimal ≠ vague; give the goal, not the micro-steps.

Source: https://www.youtube.com/watch?v=Hth_tLaC2j8

---

## 89. When Claude Errs, Write It Down — Don't Re-Prompt

Boris calls this the single most important idea for long-running work: *"Every single time Claude makes a mistake, I don't tell it to do it differently. I tell it to write it to the CLAUDE.md, or make a skill, or something. If you can do this, then Claude can just run forever."*

- **The distinction** — correcting Claude in chat fixes *this one run*; writing the fix into CLAUDE.md or a skill fixes *every future run*. A conversational correction is a patch; a written rule is a fix.
- **Why his agents run for hours** — the error rate trends down over time instead of resetting each session. The rule set compounds.
- **The mechanic** — when something goes wrong, your next instruction isn't "do it this way," it's "add a rule to CLAUDE.md / update the skill so this doesn't happen again."

Pairs with Section 4 (CLAUDE.md), Section 5 (Skills), and Section 62 (/rewind over correcting).

Source: https://www.youtube.com/watch?v=Hth_tLaC2j8

---

## 90. Why Auto Mode Is Trustworthy — Red-Teaming and Evals

Auto mode (Sections 42, 68) routes each action to a classifier instead of asking you to approve every prompt. The interview explains *why you can trust it* — and why it's arguably safer than reading every prompt yourself.

- **How it was hardened** — the team collected thousands of full agent transcripts plus the permission prompt, had auto mode classify each as safe/unsafe, then brought in red-teamers to prompt-inject and attack the codebase. Those attacks became evals; auto mode was tuned until it caught them all.
- **The counterintuitive safety argument** — Boris: *"When you accept 99% of requests, your eyes glaze over. Auto mode is more safe than reading every single permission prompt because it means you're only paying attention to the most important thing."*
- **The payoff** — because he trusts it, he can let one agent run and start a second. Trust is what makes parallel, autonomous work possible.

It protects against today's known vulnerabilities and the most intelligent attacks the team can construct. Pairs with Sections 42 and 68 (Auto Mode) and Part 11's parallel-Claudes workflow.

Source: https://www.youtube.com/watch?v=Hth_tLaC2j8

---

## 91. Nested Subagents — Agents Kicking Off Agents

Boris: *"Just landed nested subagent support in Claude Code. Starting to experiment more with agents kicking off agents as a way to better manage context. Capped at depth=5 to start."* Shipped June 9, 2026.

- **What it is** — a subagent can now spawn its own subagents, down to **depth=5** (a starting cap). Nesting is a context-management tool: each layer keeps its own context window, so deep work doesn't bloat the parent.
- **Monitor them** — to watch what each subagent is doing, hit **arrow-down** in the terminal (Boris: *"In terminal? Hit arrow down"*).
- **Model propagates, thinking weights don't (yet)** — dispatched subagents can run on a chosen model; per a user's testing that Boris confirmed, the model carries through but thinking weights do not propagate yet.
- **Works with forked sessions and Chrome** — Boris confirmed nested subagents include forked sessions and can use the Chrome browser tools.

This is the productized core of the workflows arc: where a dynamic workflow (Sections 80–86) is an orchestrated harness, nested subagents are the lower-level primitive — any agent can now delegate to keep its own context clean. Pairs with Section 6 (Subagents), Section 76 (Agent View), and Section 28 (worktree isolation for parallel edits).

Source: https://x.com/bcherny/status/2064327225504403752

---

## 92. fork: true — Run a Skill in Its Own Context Window (Experimental)

An experiment Boris shared in the same thread, framed explicitly as *"one idea I'm experimenting with"*: add **`fork: true`** to a skill's frontmatter so the skill runs in **its own context window**, then have the skill use agents to keep context isolated per step.

```yaml
---
name: my-skill
fork: true
---
```

Boris: *"add 'fork:true' to a skill's frontmatter to have it run in its own context window, then in the skill tell it to use agents to keep context isolated for each step also. Adding this to the built in /code-review skill to improve performance even more."*

- **Why** — a heavy skill (deep research, code review) can pollute or blow out the main context. Forking gives it a clean window; per-step agents (Section 91) isolate context further within it.
- **Status** — experimental, being added to the built-in `/code-review` skill. Treat as a preview, not stable API.

Pairs with Section 5 (Skills) and Section 91 (Nested Subagents). The shape echoes Section 88's context minimalism — keep each unit of work to the smallest context it needs.

Source: https://x.com/bcherny/status/2064327225504403752

---

## 93. The Dynamic-Workflows Trigger Is Now "use a workflow"

A correction to the activation trigger from Part 13 (Section 80) and Part 14. The dynamic-workflows launch said mentioning the bare word *"workflow"* in a prompt was the trigger. Boris has since refined it:

> *"Say 'use a workflow'. Just 'workflow' had too many false positives."*

- **Do this** — to launch a dynamic workflow, say **"use a workflow"** (e.g. *"use a workflow to rank these 80 resumes"*), not just the word "workflow."
- **Why it changed** — the single word triggered workflows when users didn't mean to, so the phrase was tightened.

This updates Sections 80–86 — the mechanics there are unchanged, only the trigger phrasing.

Source: https://x.com/bcherny/status/2064327225504403752

---

## 94. Fable 5 — The Best Coding Model, By a Wide Margin

Anthropic launched **Claude Fable 5** on June 9, 2026 — a **"Mythos-class"** model, now available in **Claude Code and Cowork**. The Claude announcement: *"Introducing Claude Fable 5: a Mythos-class model that we've made safe for general use. Its capabilities exceed those of any model we've ever made generally available."*

Boris's verdict: *"Fable is the best model I have used for coding, by a wide margin. It is a big step up, enabling less prompts and steers, more efficient token use, better code quality, better tool use, more intelligent self-verification, longer running sessions, and higher trust & autonomy."*

**Boris on living with it** (a day later): *"With Fable, it's felt like Claude has stepped up from being a coding agent to a thought and design partner… Fable has judgement, taste, and dimensionality in a way that previous models didn't, leading me to trust it more with the most complex work. The first time I had this realization was when I asked Fable to debug something — it's the first model I've used that was so methodical and precise, taking measurements and adding logs then verifying that it truly fixed the issue before declaring victory. There's nothing in Claude Code's prompting telling it to do that; it's just part of its personality. It really has this 'big model smell.'"* That methodical, self-verifying debugging behavior is exactly the Verification (Section 14) + Opus 4.8 honesty (Section 78) thread paying off in the base model.

- **The step-ups Boris calls out** — fewer prompts/steers · more efficient token use · better code quality · better tool use · more intelligent self-verification · longer-running sessions · higher trust & autonomy.
- **Where it lives** — Claude Code and Cowork, available now.

**The benchmarks.** Claude: *"Fable 5 is state-of-the-art on nearly all tested benchmarks… The longer and more complex the task, the larger Fable 5's lead over our other models."* Headline numbers (Fable 5 → Opus 4.8 → GPT 5.5 → Gemini 3.1 Pro):
- Agentic coding, SWE-Bench Pro: **80.3%** → 69.2% → 58.6% → 54.2%
- Frontier coding, FrontierCode/Diamond (xhigh): **29.3%** → 13.4% → 5.7% → —
- Knowledge work, GDPval-AA: **1932** → 1890 → 1769 → 1314
- Knowledge-work vision, GDP.pdf: **29.8%** → 22.5% → 24.9% → 16.7%
- Spatial reasoning, Blueprint-Bench 2: **38.6%** → 14.5% → 36.2% → 26.5%
- Computer use, OSWorld-Verified: **85.0%** → 83.4% → 78.7% → 76.2%
- Legal Agent Benchmark: **13.3%** → 10.4% → 2.1% → 0.0%

**Accuracy note:** "Fable 5" is the Mythos-class model made safe for general use; the published table reports the higher of *Mythos 5 / Fable 5* (within 1–3 pts). On the starred benchmarks — cybersecurity (ExploitBench), biology (BioMysteryBench), Terminal-Bench 2.1, Humanity's Last Exam, HealthBench — Fable 5 performs *closer to Opus 4.8* because of safety fallbacks, so treat those higher figures as Mythos 5, not Fable 5. Boris confirms the safety classifiers are currently *"trigger-happy"* — flagging ordinary debugging as cybersecurity- or biology-related — and that the team is *"working on improving it."* **Pricing** (per the Claude API pricing page) — **$10 / M input · $50 / M output**, exactly 2× Opus 4.8's $5/$25; cache write $12.50, cache read $1; Batch $5/$25; full 1M context at standard rate. So it's the best coding model, at double the price of Opus 4.8 — weigh it for cost-sensitive bulk work.

**Specs** (from the developer console) — model id `claude-fable-5`; 1M-token context; 128K max output; adaptive thinking; knowledge cutoff Jan 2026; no fast mode yet. Still emerging: Fable-specific effort levels and usage tactics.

**A second voice.** Andrej Karpathy (now at Anthropic): *"It's SOTA on everything by a margin, but… qualitatively, this is a major-version-bump-deserving step change forward… You can give it a lot more ambitious tasks than what you're used to — the model 'gets it' and it will just go. It's never felt this tempting to stop looking at the code at all (but don't do this in prod!)."* He also notes the safeguards are *"a little too trigger-happy for launch"* — the same fallback behavior behind the starred benchmarks above. See Section 95 for what it changes across the existing tips.

Source: https://x.com/bcherny/status/2064402671898075579
Source: https://x.com/bcherny/status/2064431111154053187
Source: https://x.com/claudeai/status/2064394151441863006
Source: https://x.com/karpathy/status/2064409694761054332
Source: https://platform.claude.com/docs/en/about-claude/pricing

---

## 95. What Fable 5 Changes for You

Fable 5 supersedes Opus 4.8 as the strongest coding model — which shifts a couple of earlier tips and leans harder into others.

- **It's the new default for coding.** Updates Section 2 (Model Selection) and Section 78 (Opus 4.8 was "strongest yet"). When you pick a model, Fable 5 now leads.
- **"Less prompts and steers" → lean into minimalism + delegation.** That's exactly the world Section 88 (context minimalism) and Section 65 (delegation over guidance) describe — give it the goal, not the micro-steps.
- **Longer sessions + higher trust/autonomy → the autonomy stack pays off more.** Auto mode (Sections 42, 68), /goal (77), nested subagents (91), and workflows (80–86) all benefit from a base model that self-verifies better and needs less babysitting.
- **Cost** — Fable 5 is **$10/M input · $50/M output**, 2× Opus 4.8. For high-volume or routine work, Opus 4.8 / Sonnet may still be the better economics; reach for Fable 5 where the quality jump pays for itself.
- **Caveat** — benchmarks and pricing are published, but Fable-specific effort levels and usage tactics aren't documented yet.

Source: https://x.com/bcherny/status/2064402671898075579

---

## 96. The Four Unknowns — The Map Is Not the Territory

From Thariq's (@trq212) field guide *"Finding Your Unknowns."* Working with Fable 5 keeps re-teaching an old lesson: **the map is not the territory.** The map — your prompts, skills, and context — is what you give Claude. The territory is where the work actually happens: the codebase, the real world, its actual constraints. The gap between them is what he calls your **unknowns**. When Claude hits an unknown, it makes a decision based on its best guess of what you want. *"Fable is the first model where I find the quality of the work is bottlenecked by my ability to clarify its unknowns."*

Break a problem down four ways (the Rumsfeld matrix, applied to prompting):
- **Known knowns** — what's in your prompt; what you tell the agent you want.
- **Known unknowns** — what you haven't figured out yet, but you know to ask.
- **Unknown knowns** — too obvious to write down, but you'd recognize it ("I'll know it when I see it").
- **Unknown unknowns** — what you never considered; the pothole you didn't know the road could have.

*"The best agentic coders have relatively few unknowns."* Watching someone like Boris or Jarred prompt, it's obvious they know what they want in detail and are deeply in-sync with the codebase and the model's behaviors — but they also *assume* unknowns. Reducing and planning for them is the skill of agentic coding, and it's learnable. Sections 97–99 are the toolkit, organized before / during / after implementation.

Source: https://x.com/trq212/status/2073100352921215386?s=51

---

## 97. Finding Unknowns Before Implementation

Most unknowns are cheapest to find before you write code. Thariq's pre-implementation techniques, each with a literal prompt:
- **Blind spot pass** — ask Claude to surface your *unknown unknowns* and explain them (he uses the literal words "blindspot pass"); give it context on who you are and what you know. *"I'm working on adding a new auth provider but I know nothing about the auth modules in this codebase. Can you do a blindspot pass to help me figure out my relevant unknown unknowns and help me prompt you better."*
- **Brainstorms & prototypes** — for *unknown knowns* (criteria you only recognize on sight, like visual design), have Claude brainstorm and prototype; an HTML artifact you react to beats describing it. *"I want a dashboard for this data but I have no visual taste and don't know what's possible. Make me an HTML page with 4 wildly different design directions so I can react to them."*
- **Interviews** — after brainstorming, ask Claude to interview you about remaining ambiguities. *"Interview me one question at a time about anything ambiguous, prioritize questions where my answer would change the architecture."*
- **References** — the best reference is source code. Point Fable at a folder or a module on a website and it reads the underlying code, not just the screenshot (this is also how Claude Design works).
- **Implementation plans** — ask for a plan that leads with what's most likely to change. *"Write an implementation plan in HTML, but lead with the decisions I'm most likely to tweak: data model changes, new type interfaces, and anything user-facing. Bury the mechanical refactoring at the bottom, I trust you on that part."*

Source: https://x.com/trq212/status/2073100352921215386?s=51

---

## 98. Finding Unknowns During Implementation

No matter how much you plan, there are always unknown unknowns lurking — the agent may hit an edge case mid-work that forces a different tack.
- **Implementation notes** — ask Claude Code to keep a temporary `implementation-notes.md` (or `.html`) where it logs the decisions it makes, so you can learn from them next time. *"Keep an implementation-notes.md file. If you hit an edge case that forces you to deviate from the plan, pick the conservative option, log it under 'Deviations', and keep going."*

This is the same move as Section 89 (write it down, don't re-prompt): what the agent learns mid-run becomes the map for next time instead of evaporating when the session ends.

Source: https://x.com/trq212/status/2073100352921215386?s=51

---

## 99. Finding Unknowns After Implementation

Once the work lands, the remaining unknowns are other people's — your reviewers' and your own future understanding.
- **Pitches & explainers** — getting buy-in is one of the most important parts of shipping. Package the prototype, the spec, and the implementation notes into one doc you can drop in Slack; lead with the demo. Reviewers start with the same unknowns you did, so answer them up front. *"Package the prototype, the spec, and the implementation notes into a single doc I can drop in Slack to get buy-in. Lead with the demo GIF."*
- **Quizzes** — after a long session Claude may have done more than you realized, and diffs give only a light understanding. Have Claude quiz you about the change; merge only when you pass perfectly. *"Give me an HTML report on the changes to read and understand with context, intuition, and what was done — and a quiz at the bottom on the changes that I must pass."*

**How it comes together:** the Fable launch video was edited entirely by Claude Code — a domain Thariq wasn't an expert in — by running this exact loop (start from what you know, ask Claude to explain the parts you don't, prototype with Remotion, and have it *teach* you your unknowns, e.g. color grading, rather than guess). *"The better models get, the more you can achieve with the right approach… start your next project by asking Claude to help you find your unknowns."*

Source: https://x.com/trq212/status/2073100352921215386?s=51

---

## 100. The Four Loops — A Taxonomy

From the ClaudeDevs guide *"Getting started with loops"* (@ClaudeDevs, written by @delba_oliveira). The team defines a **loop** as **an agent repeating cycles of work until a stop condition is met**. Everything from a single prompt to a cloud routine is a loop; they differ by how they're triggered, how they're stopped, which Claude Code primitive runs them, and what task fits. Not every task needs a complex loop — start with the simplest and use these selectively.

The four types, and what you hand off in each:
- **Turn-based** (the agentic loop) — triggered by a prompt; stops when Claude judges the task done. Short, one-off tasks. You hand off **the check**.
- **Goal-based** (`/goal`) — triggered by a prompt; stops when the goal is met or a turn cap is hit. Tasks with verifiable exit criteria. You hand off **the stop condition**.
- **Time-based** (`/loop`, `/schedule`) — triggered by a time interval; stops when you cancel or the work completes. Recurring work or reacting to external systems. You hand off **the trigger**.
- **Proactive** — triggered by an event or schedule with no human in real time; each task exits at its goal, the routine runs until you turn it off. Recurring streams of well-defined work. You hand off **the prompt**.

The progression matters: from turn-based to proactive you hand off more of the loop each step — the check, then the stop condition, then the trigger, then the prompt.

Source: https://x.com/ClaudeDevs/status/2074208949205881033?s=51

---

## 101. Loops You Drive — Turn-based and Goal-based

The two real-time loops, where you kick things off and stay close.
- **Turn-based, the agentic loop.** Every prompt is a loop: Claude gathers context, takes action, checks its work, repeats if needed, and responds — exiting when it judges the task complete or the effort budget runs out. The lever is verification: encode your manual check steps as a `SKILL.md` so Claude verifies its own work end-to-end, and give it tools to *see, measure, interact* (the more quantitative the check, the easier it self-verifies). Builds on Section 14 (verification) and Sections 96–99 (verification skills, Part 18). Example: a `verify-frontend-change` skill — never call a UI change done from a successful edit alone; start the dev server, interact with it, confirm zero new console errors, run a Chrome DevTools MCP performance trace, and rerun from the top if any step fails.
- **Goal-based, `/goal`.** A single turn often isn't enough; agents do better when they iterate. `/goal` defines what "done" looks like so Claude can't decide it's "good enough" and stop early — each time it tries to stop, an *evaluator model* checks your condition and sends it back until the goal is met or your turn cap is reached. Deterministic criteria (tests passing, a score threshold) work best. Extends Section 77. Example: `/goal get the homepage Lighthouse score to 90 or above, stop after 5 tries`.

Source: https://x.com/ClaudeDevs/status/2074208949205881033?s=51

---

## 102. Autonomous Loops — Time-based and Proactive

The two loops that run without you prompting each turn.
- **Time-based, `/loop` and `/schedule`.** For recurring work (same task, changing inputs — a morning Slack summary) or reacting to an external system (a PR that gets reviews or fails CI). `/loop` re-runs a prompt on an interval on your machine; turn your laptop off and it stops. Move it to the cloud by turning it into a Routine with `/schedule`. Pulls together Sections 31 (`/loop`), 43 (`/schedule`), and 61 (Routines). Example: `/loop 5m check my PR, address review comments, and fix failing CI`.
- **Proactive.** The most autonomous loop: triggered by an event or schedule with no human in real time, running in the cloud whether your laptop is open or not. You compose the primitives — `/schedule` to watch for new work, `/goal` + verification skills to define and check "done," dynamic workflows (Sections 80–86) to orchestrate triage/fix/review across many items, and auto mode (Sections 42, 68) so it never stops to ask permission. Each task exits at its goal; the routine runs until you turn it off. Example: `/schedule every hour: check the project-feedback channel for bug reports, triage each one, open a PR with a fix, and have a second agent review before notifying me`.

Source: https://x.com/ClaudeDevs/status/2074208949205881033?s=51

---

## 103. Making Loops Good — Quality, Tokens, and Which One When

A loop is only as good as the system around it.
- **Keep output quality high:** keep the codebase clean (Claude follows existing patterns), give it a way to verify its own work (encode "good" as skills), make docs easy to reach, and use a second agent for review (fresh context is less biased — the built-in `/code-review`, Section 32). When a result misses the bar, encode the fix so every future iteration improves, don't just patch the instance.
- **Manage token usage:** pick the right primitive and model (small tasks don't need a fleet; cheaper models for routine work), define clear stop criteria, pilot before a large run (dynamic workflows can spawn hundreds of agents), use scripts for deterministic work, don't over-schedule (match the interval to how often the watched thing changes), and review usage — `/usage` breaks down skills/subagents/MCPs, `/goal` with no args shows turns + tokens, `/workflows` shows per-agent usage and lets you stop one.

**Which loop when:** Turn-based → you hand off *the check*, use when exploring or deciding, reach for custom verification skills. Goal-based → *the stop condition*, when you know what done looks like, reach for `/goal`. Time-based → *the trigger*, when work happens on a schedule outside your project, reach for `/loop` / `/schedule`. Proactive → *the prompt*, when work is recurring and well-defined, reach for all of the above plus dynamic workflows. To start: pick one task where you're the bottleneck and hand off one piece — the check, the stop condition, or the trigger — then run it, watch where it stalls or over-reaches, and iterate.

Source: https://x.com/ClaudeDevs/status/2074208949205881033?s=51

---

## 104. /checkup — The One-Command Tune-Up

Setups drift: skills you stopped using, a CLAUDE.md that quietly grew to ~10k tokens, hooks that tax every turn, a version several releases behind. `/checkup` audits your whole Claude Code install and proposes fixes across seven areas — the "keep your setup lean" playbook (context minimalism, Section 88; CLAUDE.md, Section 4; write it down, Section 89) run for you in one pass.

When you run `/checkup` it can:
- **Clean up unused skills / MCPs / plugins** and save context every session.
- **Dedup your local CLAUDE.md** against the checked-in CLAUDE.md so rules aren't stated twice.
- **Break up a big root CLAUDE.md** into nested CLAUDE.md's + skills, so context loads only where relevant.
- **Turn off slow hooks** that tax every turn (Section 7).
- **Update Claude Code** to the latest version.
- **Enable auto mode by default** (Sections 42, 87).
- **Pre-approve frequently-denied read-only commands** — same idea as `/fewer-permission-prompts` (Section 69).
- …and a few other goodies.

Source: https://x.com/bcherny/status/2074997571563479143

---

## 105. /checkup is Safe by Default

The reason you can run `/checkup` on a real project without holding your breath: it never changes anything behind your back.
- **Confirms first.** `/checkup` surfaces a plan — what's broken, what's unused, what it would change — and waits. Nothing is modified until you choose an option.
- **Fully reversible.** Settings changes are one-line toggles you can flip back; CLAUDE.md edits stay in your working tree, so you review them in `git diff` before committing anything (same discipline as Section 89, write it down).
- **You control scope.** The menu ranges from *Clean up everything* (recommended one-shot) to *Let me pick* (choose which groups: install repair, unused plugins/MCP, unused skills, CLAUDE.md slimming) to *No, keep everything* (report only) to *Chat about this*.

Source: https://x.com/bcherny/status/2074997571563479143

---

## 106. /checkup — The Run

Boris ran `/checkup` on his own setup and posted the result; it caught things he didn't know were there:
- His `claude` command was **broken** — a test run had overwritten its launcher.
- **38 project skills** had never been used across **2,345 sessions**.
- His CLAUDE.md was loading **~10k tokens every session**.

Cleaning it all up repairs the install and saves **roughly 5.5k tokens of context per session** — a permanent tax lifted off every future turn. The recommended one-keystroke fix: repair the launcher, disable 3 unused plugins + the hex MCP server + 1 stray skill, turn off the 38 never-used project skills, and slim CLAUDE.md by moving ~1.9k tokens to lazy loading (reversible, as always). The lesson under the feature: setups accumulate silent waste you rarely notice until something measures it — `/checkup` is that measurement, the maintenance half of context minimalism (Section 88) automated.

Source: https://x.com/bcherny/status/2074997571563479143

---

## 107. Automation Is the Meta-Skill

Boris's throughline: the best engineers he knew always spent a lot of time automating their own work — better vim/emacs macros, lint rules to catch repeat code issues, e2e suites so they never smoke-test by hand. These were the highest-leverage activities an engineer could do, because they multiplied their own output, which meant they could build more.

With agents this matters even more. Infra and DevX automation speeds *you* up — and if you're running an army of agents, every one of those agents is sped up too. **More automation = more output per unit of time**, multiplied by the number of agents working. Pairs with parallel execution (Section 1) and loops (Sections 100–103).

Source: https://x.com/bcherny/status/2077460395279692197

---

## 108. Move Fixes From Prompts Into Code

There's a difference between fixing an issue and eliminating a *class* of issue. Your agent could fix an issue every time it sees it happen — but that uses tokens and might miss cases. If Claude instead writes a **lint rule, CI step, or routine**, that class of issue is automated forever, for every future run and every contributor.

Boris: this is *"really what people are talking about when they talk about loops — it's about automating entire types of busywork rather than solving them one off."* Not a new idea (engineers have done it for a long time), but agents make it cheap to reach for. It generalizes Section 89 (write it down, don't re-prompt): a chat correction fixes one run; encoded infrastructure fixes every run. See also loops (Sections 100–103).

Source: https://x.com/bcherny/status/2077460395279692197

---

## 109. Encode Domain Knowledge as Infrastructure

The most important reason, and the genuinely new one: automation is what makes it possible for *others* to contribute to a codebase. Engineers now contribute on day one because Claude can navigate the codebase for them, and non-engineers can contribute as effectively as engineers. What blocks both is **domain knowledge that lives in people's heads** — the stuff you used to have to learn while ramping up.

What's changed: the domain knowledge you can encode as infrastructure is no longer limited to what fits in lint rules, types, and tests. It can now capture *nearly all* domain knowledge — as code comments, **skills**, **CLAUDE.md** rules, **REVIEW.md**, docs, and memories — so an agent (or a new human) works productively with *zero additional context from the prompter*.

Boris's reframe: *"If I put up a PR for an iOS codebase I don't know and a reviewer rejects it because it doesn't use the right framework, or if a designer builds a new feature and it gets rejected because it doesn't follow the right architectural patterns, these are failures of automation."* The knowledge should have been encoded, not left in a reviewer's head. Every team should be writing the CLAUDE.md's, REVIEW.md's, skills, and docs that let agents work in their codebase with no extra prompting — a natural extension of what engineers always did: automate, and encode domain knowledge as infrastructure. Builds on CLAUDE.md (Section 4), skills (Section 5), code review (Section 32), and write it down (Section 89).

Source: https://x.com/bcherny/status/2077460395279692197

---

## 110. Give Judgement, Not Rules

The headline shift for the Claude 5 generation. Older models needed rigid guardrails to avoid worst-case behavior — but a rule that's right 90% of the time is wrong the other 10%. Newer models read the surrounding context and decide for themselves, so the team swapped hard rules for judgement. The system prompt's comment guidance is the cleanest example:

- **Then (a rule):** *"In code: default to writing no comments. Never write multi-paragraph docstrings or multi-line comment blocks — one short line max."*
- **Now (judgement):** *"Write code that reads like the surrounding code: match its comment density, naming, and idiom."*

The rule was wrong everywhere comments *were* wanted (documentation, gnarly code); judgement handles both cases without a special rule for each. This is how they deleted **over 80% of Claude Code's system prompt** for models like Opus 5 and Fable 5 with no measurable loss on coding evals. Worth a mirror: most CLAUDE.md files are still walls of hard rules. Updates Section 88 (context minimalism).

Source: https://x.com/trq212/status/2080710971228918066 · https://claude.com/blog/the-new-rules-of-context-engineering-for-claude-5-generation-models

---

## 111. Design Interfaces, Not Examples

The old number-one rule for tools was to give Claude worked examples. With the newest models, examples *backfire* — they fence Claude into the exploration space you happened to demonstrate. Design the interface instead and let expressive parameters teach usage.

The TodoWrite example: it ships no walkthrough. Its *shape* does the teaching — a `status` parameter that can only be `pending`, `in_progress`, or `completed`, plus one constraint ("only one item `in_progress` at a time"). The enum hints at the lifecycle; the constraint defines the behavior; no example needed. Ask the same of your own tools, scripts, and files: what parameters does Claude have, and how could they be *more expressive*? (Same idea for design — an HTML mockup produces better results than a description or a screenshot; see Section 113.)

Source: https://x.com/trq212/status/2080710971228918066 · https://claude.com/blog/the-new-rules-of-context-engineering-for-claude-5-generation-models

---

## 112. Progressive Disclosure Over Front-Loading

Don't cram everything a request *might* need into the prompt. Load context at the moment it's relevant — the same principle across the built-in system prompt, tools, and your own files:

- **System prompt:** code-review and verification steps moved out of the always-on prompt into **skills** Claude calls selectively.
- **Tools:** some use **deferred loading** — the agent searches for the full definition via ToolSearch before use, so tools cost no context until needed.
- **CLAUDE.md / skills:** the myth is one central repository of everything you *might* hit. Instead build a **tree of files** loaded at the right time; split long skills across many files.

And stop repeating yourself: older models leaned on repetition and end-of-context reminders, so instructions got duplicated in both the system prompt and the tool description. Newer models don't need it — put tool instructions in the **tool description only** and delete the echo. Extends Section 88 (context minimalism) and the deferred-loading model behind Section 91 (nested subagents).

Source: https://x.com/trq212/status/2080710971228918066 · https://claude.com/blog/the-new-rules-of-context-engineering-for-claude-5-generation-models

---

## 113. Auto-Memory & Rich References

Two shifts. **Memory:** you used to hand-save context to CLAUDE.md with the `#` hotkey. Now Claude **automatically saves memories** relevant to the work and to you, and loads them across sessions — memory, artifacts, and skills take over the job CLAUDE.md used to do alone. Builds on Section 45 (auto-memory) and Section 89 (write it down).

**References got richer.** A "spec" no longer means a markdown file — Claude handles far more expressive references, and code-shaped ones carry the highest fidelity:

- **HTML artifacts** — a working mockup from the artifacts feature beats a screenshot or a description.
- **Code as spec** — a function in another codebase to port, in a language Claude already knows cold.
- **Test suites** — a detailed suite is a spec that verifies itself.
- **Rubrics** — encode your taste (what good API design looks like); verifier agents in a dynamic workflow (Sections 80–86) check against it.

Source: https://x.com/trq212/status/2080710971228918066 · https://claude.com/blog/the-new-rules-of-context-engineering-for-claude-5-generation-models

---

## 114. Applying It to Your Own Context

The stack Claude assembles for a request, top to bottom, and what belongs in each layer:

- **Your prompt** — the one specific thing you want right now.
- **References** — @-mentioned files, specs, mockups, codebases, artifacts.
- **System prompt** — tied to the product; you'll rarely touch it in Claude Code (spend real time here only if you're building your own agent harness).
- **CLAUDE.md** — lightweight: what the repo is for, and the *gotchas*. Skip the obvious; push detail into skills via progressive disclosure.
- **Skills** — lightweight guides for your opinions and best practices; avoid over-constraining except in high-stakes areas.
- **Memory** — now automatic.

If you can't tell what to cut, run the new `claude doctor` command (`/doctor` in Claude Code) — it rightsizes your skills and CLAUDE.md automatically, the context-engineering twin of Section 104 (`/checkup`).

Source: https://x.com/trq212/status/2080710971228918066 · https://claude.com/blog/the-new-rules-of-context-engineering-for-claude-5-generation-models

---

## 115. Opus 5 — And the Model That's Hardest to Inject

These rules ship for a reason: **Opus 5** landed the same day, state-of-the-art on coding and knowledge-work evals (agentic terminal coding, GDPval, ARC-AGI-3, computer use). But the eval scores aren't what Boris led with — it's that Opus 5 is Anthropic's **least prompt-injectable model yet**. Across prompt-injection evals and red-teaming it's very hard to inject, and layering the defenses — strong model alignment, prompt-injection probes, and **Auto Mode** in Claude Code — drives the attack success rate to **~0**.

Boris: *"More than any of these eval scores, what is most exciting to me is something else: Opus 5 is our least prompt injectable model yet."* That's the foundation the new rules stand on: judgement-based context engineering only works if you can trust the model to reconcile conflicting, attacker-adjacent context safely. Pairs with Section 90 (why auto mode is trustworthy).

Source: https://x.com/bcherny/status/2080713091688583312

---

## Quick Reference

| Tip | Key Action |
|-----|------------|
| Parallel work | Use git worktrees, 3-5 sessions |
| Model | Opus with thinking |
| Planning | Start in plan mode for complex tasks |
| CLAUDE.md | Update after every correction |
| Skills | /simplify, /batch, /btw, custom workflows |
| Subagents | Offload to keep context clean |
| Hooks | PostToolUse, SessionStart, PermissionRequest, Stop |
| Permissions | Pre-allow safe commands, wildcards |
| MCP | Integrate Slack, BigQuery, Sentry |
| Long-running | Use Stop hooks, background agents |
| Verification | Chrome extension, browser testing |
| Learning | Use Claude to explain and teach |
| Terminal | /config, /voice, /color, keybindings |
| Effort | /effort max for deeper thinking |
| Plugins & Agents | LSPs, MCPs, --agent, custom agents |
| Sandboxing | /sandbox for file & network isolation |
| Status line | /statusline for custom info display |
| Customize | Spinners, output styles, 37 settings, 84 env vars |
| Worktrees | claude -w, Desktop, subagent isolation, non-git VCS |
| Scheduled Tasks | /loop, /schedule, automated workflows |
| Code Review | Agent-powered PR reviews that catch real bugs |
| Remote Control | Teleport, mobile app, /remote-control |
| Session Management | --name, /branch, --fork-session, auto-naming |
| Setup Scripts | Automate cloud environment setup |
| PostCompact | Hook for context compression events |
| Auto Mode | Safer permission skipping with classifiers |
| iMessage | Text Claude from any Apple device |
| Auto-Memory & Dream | Persistent, self-cleaning memory system |
| Mobile App | Code from iOS/Android Claude app |
| Cowork Dispatch | Remote control for Claude Desktop |
| Desktop App | Auto start and test web servers |
| --bare | 10x faster SDK startup |
| --add-dir | Give Claude access to more folders |
| Routines | Scheduled and event-driven Claude Code runs |
| /rewind | Drop failed attempts from context, re-prompt from a prior turn |
| /compact vs /clear | Lossy LLM summary vs hand-written brief — know which to use |
| Auto-compact window | `CLAUDE_CODE_AUTO_COMPACT_WINDOW=400000` to dodge context rot |
| Delegation over Guidance | Treat Opus 4.7 like an engineer you delegate to, not a pair programmer |
| Full Task Context Upfront | Goal + constraints + acceptance criteria in the first turn |
| xhigh effort | New default reasoning level for Opus 4.7. Use `/effort` to adjust |
| Auto Mode + Parallel Claudes | No babysitting — run a fleet of Claudes in auto mode |
| /fewer-permission-prompts | Scan history, tune your permission allowlist |
| Recaps | Short summary of what happened and what's next |
| Focus Mode | `/focus` — hide intermediate work, see only the final result |
| Effort Mastery | xhigh for most, max for hardest. Max is session-only |
| /go | Verify end-to-end + /simplify + put up a PR |
| 4.6→4.7 Shifts | Calibrated length, less auto-tool-use, judicious subagents |
| Task Notifications | Hooks and alerts for autonomous runs |
| Agent View | `claude agents` from root code dir — one list of sessions grouped by needs input / working / completed |
| /goal | Set a completion condition; Claude keeps working until it's met (Ralph loop built into Claude Code) |
| Opus 4.8 | Strongest coding model yet. SWE-Bench Pro 64.3 → 69.2. More honest — catches its own bugs instead of declaring victory early. Same price as 4.7 |
| High-Effort Default + xhigh | 4.8 defaults to high effort (same tokens as 4.7, better output); xhigh for hard async work; raised Claude Code rate limits |
| Dynamic Workflows | Research preview: say "use a workflow" to trigger (see Section 93). Orchestrator → implementer → 2 verifiers → fixer per task; hundreds of tasks in parallel. Default to auto mode. Save for migrations / refactors / perf / batch bug fixes / catalogue-and-categorize sweeps |
| Workflow Failure Modes | Workflows fix three single-context failures: agentic laziness, self-preferential bias, goal drift — by giving separate agents isolated goals |
| Workflow Primitives | `agent(prompt, opts)` with schema/model/isolation; `parallel([fns])` is a barrier; `pipeline(items, ...stages)` has none. JS file, resumable. Dynamic harness > generic static one |
| Workflow Patterns | classify-and-act · fan-out-and-synthesize · adversarial verification · generate-and-filter · tournament · loop-until-done |
| Workflow Use Cases | Bun's Zig→Rust rewrite, deep research/verification, sort 1000+ via tournament, one-verifier-per-rule, root-cause from disjoint evidence, triage with quarantine |
| Workflow Budgets | Cap with "use 10k tokens". Pair with /goal (hard finish) + /loop (repeat). "quick workflow" for small jobs. Skip for routine coding |
| Saving Workflows | Press "s" in the workflow menu; check into ~/.claude/workflows; share via a skill as a template; "ultracode" forces a workflow |
| Auto Mode Retired Plan Mode | Boris dropped plan mode for auto mode on Opus 4.6+ — newer models don't need a planning step |
| Context Minimalism | Minimal system prompt + minimal tools; let the model pull the rest. Prompt eng → context eng → minimalism |
| Write It Down, Don't Re-Prompt | Every mistake → CLAUDE.md or a skill, not a chat correction. That's how Claude runs for hours |
| Why Auto Mode Is Trustworthy | Thousands of transcripts classified + red-teamed into evals; safer than glazing over every prompt |
| Nested Subagents | Agents kick off agents, depth=5; manage context by nesting. Monitor with arrow-down in terminal; model propagates, thinking weights don't yet |
| fork: true (experimental) | Add to a skill's frontmatter to run it in its own context window; pair with per-step agents. Being added to /code-review |
| Workflow Trigger | Say "use a workflow" (not bare "workflow" — too many false positives). Mechanics of Sections 80-86 unchanged |
| Fable 5 | June 9 2026: Anthropic's "Mythos-class" model, in Claude Code + Cowork. Boris: best coding model "by a wide margin" — less steering, better self-verification, longer sessions, higher autonomy |
| Fable 5 — What Changes | New default coding model (supersedes Opus 4.8); leans into minimalism + delegation; pairs with the autonomy stack. Best-practices still emerging |
| The Four Unknowns | Map (prompts/context) vs territory (codebase/reality); the gap is your unknowns. Known knowns / known unknowns / unknown knowns / unknown unknowns. Planning for them is the skill |
| Unknowns — Before | Blindspot pass (unknown unknowns), brainstorms & prototypes (unknown knowns), interviews (one Q at a time), references (source code beats screenshots), implementation plans (lead with what changes) |
| Unknowns — During | `implementation-notes.md`: have the agent log deviations and keep going, so next time is smoother |
| Unknowns — After | Pitches & explainers (package prototype + spec + notes, lead with the demo, for buy-in); quizzes (Claude quizzes you — merge only when you pass) |
| The Four Loops | Loop = agent repeating cycles until a stop condition. Turn-based (hand off the check), goal-based /goal (the stop condition), time-based /loop /schedule (the trigger), proactive (the prompt) |
| Loops You Drive | Turn-based: encode verification as a SKILL.md so Claude self-checks. Goal-based: /goal + evaluator model checks your condition until met or turn cap; deterministic criteria work best |
| Autonomous Loops | /loop (local) + /schedule (cloud Routine) for recurring/external work; proactive = compose /schedule + /goal + skills + dynamic workflows + auto mode, event-driven, no human |
| Making Loops Good | Quality: clean codebase, verification skills, second-agent /code-review. Tokens: right primitive/model, clear stop criteria, pilot first, scripts, don't over-schedule, /usage + /workflows |
| /checkup | One-command setup tune-up: cleans unused skills/MCPs/plugins, dedups & slims CLAUDE.md, turns off slow hooks, updates Claude Code, enables auto mode, pre-approves read-only commands |
| /checkup — Safe | Confirms before changing anything; fully reversible (one-line toggles + CLAUDE.md edits in git diff); scope from "clean everything" to "report only" |
| /checkup — The Run | Boris's result: broken launcher, 38 skills unused in 2,345 sessions, ~10k-token CLAUDE.md; cleanup saves ~5.5k tokens/session |
| Automation Is the Meta-Skill | Automating your own work (vim/lint/e2e) is the highest-leverage thing; with a fleet of agents every automation multiplies across all of them |
| Fixes Into Code | Don't re-fix an issue each run — Claude writes a lint rule / CI step / routine so the class is automated forever (what "loops" means) |
| Domain Knowledge as Infra | Encode it as CLAUDE.md, REVIEW.md, skills, docs, comments, memories so agents & new contributors need zero extra context; a rejected PR is a failure of automation |
| Judgement, Not Rules | Claude 5 reads context and decides — delete rigid guardrails; the team cut 80%+ of the system prompt with no eval loss. "Write code that reads like the surrounding code" |
| Interfaces, Not Examples | Examples fence Claude in; expressive parameters teach usage — a status enum + "only one in_progress" (TodoWrite) with no example |
| Progressive Disclosure | Load context when needed: skills over baked-in steps, deferred tool loading via ToolSearch, a tree of files; tool instructions in the tool description only |
| Auto-Memory & Rich References | Claude auto-saves memories now; reference HTML artifacts, code, test suites, and rubrics (checked by verifier agents) instead of plain markdown specs |
| Apply It / /doctor | Stack: prompt → references → system prompt → CLAUDE.md → skills → memory. Keep CLAUDE.md to purpose + gotchas; run /doctor to rightsize skills & CLAUDE.md |
| Opus 5 | SOTA on coding + knowledge work, and the least prompt-injectable model yet — alignment + PI probes + auto mode drive attack success to ~0 |

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*Source: [howborisusesclaudecode.com](https://howborisusesclaudecode.com) - Tips from Boris Cherny and the Claude Code team's January–July 2026 threads*