Bitcoin (wallet-sdk-core granular skill)

Granular skill for BitcoinWalletProvider — the low-level Bitcoin wallet for backend / Node / non-React flows. Source-of-truth reference lives in the parent broad skill's knowledge tree; this file is the focused workflow only.

Step 1 — Clarify with user before coding

1. New code or v1 → v2 port? New → § Integration. Port v1 → § Migration (almost always a no-op here).
2. Private-key or browser-extension config? Bitcoin discriminates by an explicit uppercase type ('PRIVATE_KEY' | 'BROWSER_EXTENSION') — not field presence. PK = { type: 'PRIVATE_KEY', privateKey, network, addressType? }; browser-extension = { type: 'BROWSER_EXTENSION', walletsKit, network }.
3. Which message-signing scheme? signBip322Message (modern, structured) vs signEcdsaMessage (legacy signmessage) — pick based on what the verifier expects.

Integration workflow (new v2 code)

1. ../integration/knowledge/ai-rules.md — DO / DON'T (read first).
2. ../integration/knowledge/architecture.md — BaseWalletProvider, dual-config discriminants, shallow defaults merge, library-exports.
3. ../integration/knowledge/features/bitcoin.md — full config union, BitcoinWalletDefaults, BitcoinWalletsKit shape, methods (signTransaction / signEcdsaMessage / signBip322Message / sendBitcoin), gotchas.
4. Setup recipe → ../integration/knowledge/recipes/setup-private-key.md or ../integration/knowledge/recipes/setup-browser-extension.md; then ../integration/knowledge/recipes/sign-and-broadcast.md, ../integration/knowledge/recipes/defaults-and-overrides.md.
5. Lookups → ../integration/knowledge/reference/provider-classes.md, interfaces.md, chain-support.md.

Bitcoin-specific anti-patterns