Claude Skills by claude-dev-suite

@scure/btc-signer: modern audited Bitcoin signer in TypeScript. Pure functional, minimal dependencies, browser-friendly. USE WHEN: building modern web/mobile Bitcoin apps, evaluating bitcoinjs-lib alternative.

libsecp256k1: the canonical secp256k1 C library. Used by Bitcoin Core, rust-secp256k1, all major language bindings. USE WHEN: low-level crypto in C/C++, building bindings, performance- critical paths.

rust-secp256k1: Rust bindings to libsecp256k1 (C). ECDSA, Schnorr, ECDH, key tweaking, MuSig2 (in newer versions). USE WHEN: low-level crypto in Rust, working with raw secp256k1 operations.

taproot-assets daemon (tapd): Go implementation of Taproot Assets Protocol by Lightning Labs. Companion to LND. USE WHEN: integrating with tapd, building Taproot Assets apps in Go.

Multi-Path Payments (MPP) — split a payment across multiple parallel routes; same payment hash, payment_secret binds parts. AMP (Atomic Multipath) — variant where each part has different hash; receiver derives shared secret. USE WHEN: implementing payment splitting, debugging "couldn't route full amount", evaluating MPP vs AMP.

BOLT12 offers: reusable invoices, blinded paths, recurring payments, multi-asset (Taproot Assets layered). Replaces BOLT11 for many use cases. USE WHEN: implementing/integrating offers, designing recurring payments, evaluating BOLT11 vs BOLT12 trade-offs.

BOLT (Basis of Lightning Technology) specification index. Wire format, channel management, onion routing, gossip, invoices, feature bits. Quick refs: BOLT-by-BOLT summary, message-type tables, feature-bit registry. USE WHEN: implementing/reading Lightning protocol, looking up message types, debugging interop between implementations.

Channel jamming attacks: slow-jam (long-held HTLCs exhaust slots), fast-jam (rapid hold/release exhausts liquidity). Mitigations: upfront fees, reputation, hold-fee proposals. USE WHEN: assessing LN security model, designing reputation systems, evaluating jamming-resistant routing.

Lightning channel mechanics: funding tx, commitment tx, anchor outputs, to_local / to_remote outputs, dual-funded (v2), zero-conf, wumbo, taproot channels, splicing. Quick refs: state machine, commitment tx structure, force-close flow. USE WHEN: opening/closing channels, debugging force-closes, designing channel UX, evaluating anchor vs static-remote-key tradeoffs.

Core Lightning (CLN, formerly c-lightning) by Blockstream: lightningd, lightning-cli, plugin architecture (Python pyln-client, Rust cln-plugin, Go glightning), commando, BOLT12 leadership. USE WHEN: integrating with CLN, writing plugins, debugging CLN-specific behaviour, leveraging BOLT12 features.

Consumer Lightning wallet integration patterns: Phoenix, Breez SDK, Mutiny, Zeus, BlueWallet (LN), Aqua. Custodial vs non-custodial, LSP partnerships, mobile-specific UX (push notifications, background sync). USE WHEN: integrating with consumer wallets, designing self-custodial mobile UX, evaluating wallet SDK options.

Eclair Lightning implementation by ACINQ: Scala/Akka, eclair-cli, plugin system, primarily backend service. Powers Phoenix wallet's server side and ACINQ's main routing node. USE WHEN: deploying Eclair as backend, integrating with ACINQ's Phoenix backend, evaluating Scala/JVM Lightning options.

BOLT 7 gossip: node_announcement, channel_announcement, channel_update. Sync via gossip_queries, channel range queries, gossip rate limiting, pruning stale announcements. USE WHEN: implementing/debugging gossip sync, managing graph storage, designing rate limits.

Greenlight by Blockstream: hosted CLN with self-custodial signing. Server runs the full CLN node; user retains private keys via signer protocol. Mobile-friendly without running a full LN node. USE WHEN: building mobile/web LN apps with self-custody but no on-device daemon, integrating with Blockstream's hosted infra.

HTLC (Hash Time-Locked Contract) lifecycle: offered/received, fulfill via preimage, fail/timeout, 2nd-stage txs. Modern variant PTLCs (Point Time-Locked Contracts) with adaptor signatures. USE WHEN: implementing payment forwarding, debugging stuck HTLCs, reasoning about CLTV deltas in routes.

Keysend / spontaneous payments: send Lightning to a destination without an invoice. Receiver derives preimage from sender-supplied TLV record. BOLT 9 bit 50. USE WHEN: implementing tipping flows, designing zero-friction micro-payments, evaluating keysend vs BOLT11 invoice flow.

LDK (Lightning Dev Kit) by Lightning Labs: modular Rust crates for building custom Lightning apps. ldk-node for opinionated quick-start. ChannelManager, ChainMonitor, Router, async signer, persistence. USE WHEN: embedding Lightning into mobile/desktop apps, building custom Lightning logic, scaling beyond LND-style daemon.

Lightning Address (LUD-16): email-style identifier resolving to LNURL-pay endpoint. user@domain.com → /.well-known/lnurlp/user. USE WHEN: building/registering Lightning Addresses, designing resolver / payer wallet logic.

LND (Lightning Network Daemon) by Lightning Labs: gRPC + REST API, macaroons, lncli, autopilot, channel backups (SCB), Tor support, watchtowers, integration with bitcoind/btcd/Neutrino backend. USE WHEN: integrating with LND, scripting lncli, debugging LND-specific issues, designing LND-based services.

LNURL: bech32-encoded HTTP URL fetched by wallet to enable payment flows. LUDs (LNURL specs): LUD-01 (encoding), LUD-04 (auth), LUD-06 (pay), LUD-09 (success action), LUD-12 (comment), LUD-16 (lightning address), LUD-21 (verify). USE WHEN: implementing LNURL servers/clients, building Lightning Address resolver, designing pay/withdraw/auth flows.

Lightning Labs liquidity tools: Loop (off-chain ↔ on-chain swaps), Pool (auction-based liquidity market), Lightning Terminal (Lit, web UI). Submarine swap mechanics behind Loop. USE WHEN: managing channel liquidity, evaluating Loop vs Boltz vs Peerswap, deploying Lit for fleet management.

LSP (Lightning Service Provider) specifications: BLIPs, JIT channels, on-pay channel open, MPP-trampoline, BOLT12 hosted invoice. Major LSPs: ACINQ (Phoenix backend), Voltage, Olympus, Megalith, Flashsats. USE WHEN: integrating with an LSP, designing LSP services, evaluating LSP options for a wallet.

Nostr Wallet Connect (NWC, NIP-47): wallet remote control via Nostr relays. App on one device drives wallet on another via signed JSON messages over Nostr. USE WHEN: integrating wallet-side or app-side NWC, designing remote-control flows, evaluating NWC vs WebLN.

Sphinx onion routing for Lightning (BOLT 4): packet structure, per-hop encryption, payload TLV, blinded paths, onion messages. USE WHEN: implementing onion construction/decryption, debugging routing payloads, designing onion-based off-chain protocols.

Phoenixd by ACINQ: headless server build of Phoenix wallet for self-hosting. Single-node Lightning daemon with batteries-included ACINQ swap-in / swap-out, BOLT12 receive, WebSocket payments API. USE WHEN: deploying a self-hosted minimal Lightning daemon for a service (point-of-sale, donation page, micro-merchant), avoiding full LND/CLN complexity.

Pinning attacks: low-fee descendant txs block honest fee-bumping by exploiting mempool descendant policy. Anchor outputs (BOLT-3), TRUC v3 (BIP431), and ephemeral anchors as defenses. USE WHEN: auditing fee-bump robustness, evaluating channel security, reviewing post-2024 LN deployments.

Replacement cycling attack on Lightning (Riard 2023): exploits BIP125 rule 5 to indefinitely delay an honest HTLC-timeout, costing the victim. Mitigated by TRUC v3 + ephemeral anchors. USE WHEN: auditing LN security posture, evaluating fee-bumping strategies, understanding why TRUC was activated.

Lightning pathfinding and routing: cost models, MPP / AMP / trampoline, blinded paths (BOLT 4 update), apriori probability, pickhardt-payments. USE WHEN: implementing/tuning a routing algorithm, debugging "no route" errors, evaluating pathfinding strategies.

Channel splicing: splice-in (adding capacity) and splice-out (withdrawing) without closing the channel. Replaces "close and reopen" with one splice tx. USE WHEN: increasing/decreasing channel capacity in production, designing dynamic-balance LSP integrations, planning channel lifecycle.

Submarine swaps: atomic on-chain ↔ Lightning conversions via shared HTLC preimage. Boltz protocol, Loop protocol, Peerswap (P2P), trustless variants with adaptor signatures. USE WHEN: building swap services, integrating with Boltz/Loop, designing trust-minimized swap flows.

Simple Taproot Channels (BOLT 9 bit 56): MuSig2-aggregated funding output, Tapscript commitment leaves, taproot-native HTLCs. USE WHEN: enabling taproot channels in your impl, evaluating cooperative-spend privacy gains, designing taproot HTLC scripts.

Trampoline routing: outsource pathfinding to "trampoline" nodes for clients that lack full graph knowledge. Mobile-friendly. CLN and LDK lead implementation. USE WHEN: implementing trampoline-aware sender/receiver, evaluating trampoline vs full pathfinding.

UMA (Universal Money Address): Lightspark's spec extending Lightning Address with non-USD currencies, KYC compliance, sender attestation, multi-currency exchange via Lightning routing. USE WHEN: integrating with UMA-enabled providers (mostly enterprise), building cross-currency LN payment flows.

Watchtower architecture: encrypted breach blob storage, justice transactions, monitoring outsourced for offline channels. Eltoo proposal alternatives, BOLT 13 (proposed). USE WHEN: deploying a watchtower service, evaluating watchtower vendors, designing self-hosted monitoring.

WebLN: browser API for Lightning. window.webln exposed by wallet extensions / mobile webviews. Methods: enable, getInfo, sendPayment, makeInvoice, signMessage. Bitcoin Connect (modern wrapper). USE WHEN: building web apps with Lightning payments, integrating with Alby/getalby, designing WebLN-compatible flows.

Atomicals protocol: alternative metaprotocol family with ARC-20 (fungible) and AVM (Atomicals VM) for richer logic. UTXO-bound digital objects. USE WHEN: working with Atomicals, comparing with Ordinals / Runes.

BRC-20: fungible token standard via JSON inscriptions. Deploy / mint / transfer operations. Permissionless and unaudited; large ecosystem post-2023. USE WHEN: building BRC-20 tooling, evaluating token issuance on Bitcoin, comparing with Runes / Taproot Assets.

Inscriptions: arbitrary data committed to specific sats via Taproot envelope structure. Foundation for BRC-20, recursive inscriptions, "Bitcoin NFTs". USE WHEN: creating/parsing inscriptions, debugging inscription flow, evaluating inscription cost / fee impact.

Ordinal theory: numbering scheme for individual satoshis (sat ordinals). ord client, sat-tracking, rare sat collecting, foundation for inscriptions / BRC-20 / sub-protocols. USE WHEN: working with ord client, tracking sats, building Ordinals apps.

Runes: Casey Rodarmor's UTXO-native fungible token protocol. Activated at halving April 2024. Smaller on-chain footprint than BRC-20, native validation rules. USE WHEN: building Runes apps, comparing with BRC-20 / Atomicals.

Decentralized mining pools: Public-Pool, BraiinsP2Pool, Solo CKPool, Datum (Ocean). Reduce centralization vs traditional pools. USE WHEN: solo mining, evaluating decentralized options, building censorship-resistant infrastructure.

Difficulty adjustment algorithm: 2016-block re-target window, max 4x factor, time-warp considerations, real-world hashrate dynamics. USE WHEN: predicting next adjustment, understanding hashrate/ difficulty cycles, building mining analytics.

ASIC mining firmware: Braiins OS+, Vnish, BUMa, stock firmware, custom firmware tradeoffs. Overclocking, undervolting, autotuning, efficiency curves. USE WHEN: deploying mining firmware, evaluating efficiency vs hashrate, choosing custom vs stock.

Mining pool reward schemes: PPS, FPPS, PPLNS, PPS+, Score, prop. Block generation queue, share variance, payout cycles. Solo mining vs pooled. USE WHEN: comparing pools, designing reward systems, understanding miner economics.

Bitcoin Proof of Work: SHA256d on block header, target, nonce iteration, hashrate, mining math. USE WHEN: explaining mining mechanics, debugging mining software, designing mining-related apps.

Stratum V1: TCP/JSON protocol between mining pool and miners. Subscribe, authorize, mining.notify, mining.submit. Most-used protocol but security/decentralization weaknesses. USE WHEN: integrating mining hardware, building pool / proxy software, debugging hash submission.

Stratum V2: encrypted, miner-driven mining protocol. Job Declaration, Template Provider, allows miners to choose their own tx set. Defeats pool-level censorship. USE WHEN: deploying SV2-capable mining infrastructure, evaluating V1 vs V2, integrating with Braiins Pool / Datum.

Cross-chain atomic swaps: BTC ↔ LTC / BTC ↔ Liquid / BTC ↔ Monero via HTLC or adaptor signature schemes. Trustless swaps without centralized exchange. USE WHEN: building atomic swap services, evaluating cross-chain bridges, integrating with COMIT / submarine-swap variants.

BIP47 PayNyms — reusable payment codes via notification tx + Diffie-Hellman derivation. See also the wallet-side reference at ../../wallets/payment-codes/. USE WHEN: integrating PayNyms, evaluating against Silent Payments.

CoinJoin: collaborative tx where multiple users combine inputs to break common-input-ownership heuristic. Wabisabi (Wasabi 2.0), Whirlpool (Samourai), JoinMarket maker/taker. USE WHEN: implementing CoinJoin coordinator/client, evaluating privacy gain, designing post-CoinJoin hygiene.