open-second-brain

Use Open Second Brain to read, write, and maintain an agent-owned second brain in an Obsidian-compatible Markdown vault. The agent owns one top-level directory (`Brain/`). User-authored notes live wherever the operator names them and are read-only inputs when listed in `notes.read_paths`.

Use when adding, renaming, reviewing, or explaining Brain schema tokens, aliases, prefixes, link types, extractability, or expert routing in Open Second Brain vaults.

Use when the user explicitly mentions codegraph, asks structural code questions such as callers/callees/impact, asks where a symbol is defined, asks what breaks if a symbol changes, or asks for an architectural overview of a code repository. Skip for prose-only or vault-only questions.

Bring Open Second Brain semantic search online — embedding API key, sqlite-vec extension, first reindex, optional periodic refresh. INVOKE when the user mentions "embeddings", "semantic search", "vector index", or after `o2b search check` reports `vec_extension: unavailable`, `embedding_key: missing`, or any line in its `recommendations:` block. SKIP when the user is asking conceptual questions about embeddings or comparing providers without intent to set up — answer those directly.

Append-only operational event logging for Open Second Brain. Daily Markdown notes are the default backend. INVOKE this skill (and call `event_log_append`) immediately after producing any durable artifact in the current turn — code shipped, bug fixed, refactor merged, config or deployment change, instruction-file edit (CLAUDE.md / AGENTS.md / plugin docs / system prompts), content artifact created (post, draft, documentation, marketing copy, release notes), research or investigation that produced a concrete finding or decision worth recalling later, or discovery of an external fact (CLI behaviour change, API quirk, undocumented edge case) that future sessions should know. SKIP for pure discussion, exploration, read-only queries, and planning that has not yet produced an artifact. If unsure, ask "would future-me want to find this in the log by searching for it later?" — if yes, log it. WRITE the `message` in the same natural language the user has been speaking with you in this session — never default to English