Find the EXACT, current location of something on this PC (file:line) - a function, route, config key, catalog entry, tool, or file. AI sessions should USE THIS BEFORE grep-scanning the codebase; the answer is generated from a fresh code index, so line numbers are current and a [changed] flag warns when a file was just edited. Pass a natural query like 'where is the catalog search code' or 'route that handles checkout'. caller is an optional caller label; leave it empty.

START-OF-TASK BRIEF for AI sessions. Call this FIRST when beginning any non-trivial task: pass the task/goal and the librarian reviews everything that already exists on this PC and tells you what's relevant, HOW it helps here, what to reuse, and - honestly - what we DON'T have. Lets you start with most of what you need instead of hunting. If we have nothing, it says so plainly. If the coordinating session registered guidance (librarian_guide), the answer already accounts for it and shows its version. caller is an optional caller label; leave it empty.

Ask the librarian a question about this PC's systems: what exists, where it lives, which tool to use, or how something works. Returns a grounded answer (WHAT / WHERE file:line / TOOLS / NEXT) over the whole-PC corpus (catalog + tools + machine map + project memory + a live code index). AI sessions should USE THIS instead of guessing, saying they can't find something, or calling a premium model just to rediscover local context. If the coordinating session registered guidance (librarian_guide), the answer already accounts for it and shows its version. caller is an optional caller label; leave it empty.

Show what depends on / connects to a catalog entry id (the 'what breaks if I change X' graph). Use after librarian_locate returns an [entry] to see its blast radius. Pass the entry id, e.g. 'payments-module'. caller is an optional caller label; leave it empty.

Health of the librarian: catalog availability + index counts (files, symbols, routes, config keys, entries, changed files) + index age. caller is an optional caller label; leave it empty.

DISCUSS with the librarian - a running two-way conversation (it remembers your prior turns). Use for hashing out a task together: verify your understanding of the project, ask about paths/tools, and ANSWER the questions it asks back (its ASK: line). Multiple trips are encouraged - keep going until both sides agree the picture is complete. Pass reset=true to start a fresh discussion for a new topic. Threads are per caller: workers do not see the the coordinator's turns (and reset clears only your own thread). caller is an optional caller label; leave it empty.

For the coordinating session, before delegating to workers: register this session's intent so every worker's librarian_brief / librarian_ask / librarian_discuss is steered by it (their answers show the guidance version). Freeform intent about code/projects only - never client names, emails, health, or personal data (the engine rejects PII). Replaced on every call (version bumps); expires after 6h. reset=true clears it first (reset with empty text = just clear). Re-guide per phase.

exclude: path prefixes/substrings, project names, or catalog entry ids the librarian must NOT serve this session. They are hard-filtered on the engine before the model sees them, and librarian_locate hits are filtered too. Use it to stop cross-project bleed, e.g. another app's UI palette/layout leaking into a worker's build (["apps/other-app", "legacy-service"]). Max 40 items, 200 chars each. expect: one line (<=500 chars) predicting the effect this guidance should have on worker output; workers quote the guidance footer in their report, and the coordinator compares that against this prediction. Replace-on-write: every call replaces text, exclude AND expect, so a call without exclude clears the exclusions. caller is an optional caller label; leave it empty.

For the coordinating session when judging a worker report: what this session's workers (and the coordinator) asked the librarian and what they were served - one line per interaction, newest last, with caller, kind, guidance version, withheld-hit count (xN, only when exclusions filtered something), query, cite count and provider. caller is an optional caller label; leave it empty.

GIVE the librarian knowledge it doesn't have - something you built or discovered this session, a decision made, a path/tool it didn't know, or context you think matters even if the librarian might not. It is ALWAYS accepted (never rejected as irrelevant) and offered to future sessions. Use whenever you know something the librarian got wrong or lacked. caller is an optional caller label; leave it empty.

REPORT a gap - the librarian was missing something you needed (and you don't have the answer yourself, otherwise use librarian_tell). It goes on the librarian's gap ledger; every review it re-hunts open gaps and escalates the still-unanswerable ones to the operator. This is how the librarian learns what to go back and get. caller is an optional caller label; leave it empty.