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Librarian

The Librarian is jkz’s memory desk. It does not create knowledge — it makes existing knowledge findable. When an agent or a human asks “what did we decide about X?” or “where is the pattern for Y?”, the Librarian answers with a citation back to the source, never a guess.

ModelClaude Haiku 4.5
Classutility
PhaseAny — a cross-phase support role
Invocationnode scripts/librarian.js <subcommand>, or the MCP tool librarian_query

Mission

Index, organize, and retrieve. The Librarian is read-only by design: it never modifies a source file, opens a PR, or posts a comment. Its single job is recall — turning the project’s accumulated history into a searchable answer with a source attached.

What it reads

The knowledge base is built from four sources:

  1. Memory files — MEMORY.md, project instructions, CLAUDE.md.
  2. Deliberations — past agent responses, verdicts, ADRs, and accumulated patterns.
  3. Pipeline state — phase transitions, issue types, iteration counts.
  4. Cross-chat registry — knowledge from other sessions, when available.

How retrieval works

Two phases. First, an FTS5 BM25 search runs locally and fast — it returns the top-ranked matches in well under a second. Then Haiku synthesizes those matches into a concise answer with the sources cited inline. If Haiku is unavailable, the raw FTS5 results are returned directly rather than nothing at all.

Indexing is incremental by default: the index-latest subcommand only processes files changed since the last run, which is what the session hooks call.

The rules it lives by

  • Read-only. It never changes source files, creates PRs, or posts comments.
  • Always cite. Every answer references the file or deliberation it came from.
  • No fabrication. If the knowledge base has no answer, it says so. It never invents one.

That last rule is the point of the role. A search engine that occasionally makes things up is worse than no search engine — so the Librarian would rather return “not found” than a plausible fiction. It is the same evidence discipline the rest of the pipeline runs on, applied to recall.