Retention Probe

---
name: retention-probe
description: Tests if this session still holds the always-on instruction file. Use when a repo rule seems missing, in a new subagent or after compaction.
---
<!-- Generated by `basicly skills-build` from skill.yaml. Do not edit; edit the source. -->

# Retention Probe

Test one thing: is the always-on instruction file in the context of this session?

## Rules

- **Answer from memory only.** Do not read, search or list files first, because the probe detects whether you already have the file.
- **Answer exhaustively.** A short answer scores as a missing file.
- **Run it when you suspect a problem, not on a schedule.** The probe output repeats every rule, so each run puts the rules back into context.
- **Do not read the score as adherence.** A recited rule is not an obeyed rule. A gate or a `PreToolUse` hook enforces a rule.
- **Do not read a high score as memory.** While the file is in context you read it. You do not recall it.

## Procedure

1. Write every rule, convention and constraint that you believe governs this repository to a scratch file, one per line.
2. Score the file:

   ```sh
   uv run basicly retention <scratch-file>
   ```

   | Flag | Effect |
   | --- | --- |
   | `--verbose` | Lists each rule that did not come back, beside the nearest line of your answer |
   | `--baseline <path>` | Scores against another file. The default is the first of `.claude/CLAUDE.md`, `CLAUDE.md` and `AGENTS.md` |
   | `--strict` | Exits non-zero when the verdict is absent |

   Pass `-` in place of the file to read the answer from stdin.
3. Act on the verdict.

## Verdicts

| Verdict | Meaning | Action |
| --- | --- | --- |
| `LOADED` | 80% or more. The file is in context. | None. |
| `PARTIAL` | Between 30% and 80%. Not decisive. | Run again once, with a fuller answer. |
| `ABSENT` | 30% or less. The file is not in context. | Read the instruction file, then continue. |
| `UNDERSAMPLED` | Fewer lines than the file has rules. | You stopped early. Answer exhaustively and probe again. |

A session that holds the file returns most of its rules. A session with no file returns almost none. So the probe is reliable for presence and useless for finer questions.

## Causes of a real ABSENT

Read the instruction file to correct each of these:

- A subagent that did not get the project instructions.
- A session that started outside the repository root.
- A `claudeMdExcludes` pattern that matches too much.
- A consumer repository where `basicly install` has not run.

A compaction is not a cause. Claude Code reads the project-root instruction file from disk again after `/compact`.

## Trend file

Each run appends one line with the rate and the verdict to `.basicly/usage/retention.jsonl`. Compare runs with each other. Do not read one number as absolute. The score is lexical and misses a distant paraphrase, so the rate is a lower limit.