Deep dive
How the library works.
The landing page says what the librarian does for you. This page says how: the three parts, the two honest modes, the security boundary, the team and the engine under it, lenses, and why none of it gets less necessary as models get smarter. Written for people who want to build the librarian or steward a library.
The library
Three parts. All three are the product.
The information model
A persistent, inspectable, provenanced model of your domain, built from whatever raw material you have: tables, documents, spreadsheets, email, APIs, and fit to a declared purpose. Every field carries its source, the method that produced it and a confidence; derived fields say they are derived. Extraction is the baseline: PDFs, scans, office and mail formats are read into the model, not left as files.
This is the artifact an agent over a database never gives you, and it is the shared understanding the librarian and its clients answer from.
The desk
Semantic-level interfaces, fit for purpose. One governed language generated from the model, offered through six surfaces for three kinds of client: conversation, HTML and a CLI for people; MCP and the language itself for agents; REST and HTTP for the applications you already run, which need no rewriting to join. Each is an access mode with a contract built in: what you may ask, in what form, what comes back, and what you are told when the answer cannot be given.
The desk works the way a reference interview does. You arrive with a question and no idea where the answer lives; the librarian establishes whether it can be answered here, in which domain, and hands you the governed query it used. You keep the query. Next time you do not need the librarian for that question, only for a new one.
The engine
The part of the library with a heartbeat. An embedded model and your manba team: agent roles that watch the sources, the model, the plant and the signals on a schedule and on cue, and act when something needs to change, through the same governed language consumers use, as proposals that must pass the library’s benchmark before they ship as a new version.
Think of the engine as a harness under everything: every role is strapped into the same language, the same ledger and the same gate, and nothing acts outside it.
Two honest modes
What the data says. Or what can be derived, labelled as derived.
When the data has the answer, the librarian says what the data says. When the direct path does not serve, it analyzes: correlates, contrasts, clusters or derives a workable answer from the sources it holds, and labels it as derived, naming the technique and the evidence. What it never does is produce an answer it cannot trace.
The data says
Deterministic lookup and governed computation. Source, transforms, freshness, confidence and completeness on every result. A sum tells you how many rows contributed.
SUM AMOUNT OF INVOICES WHERE VENDOR "Acme" AND MONTH "2026-10" → 14,210.00 · 12 of 14 invoices carry an amount · epoch 41
Derived, and says so
A value the data does not state outright can still be derived for you, with the derivation disclosed: which sources, which method, why it was triggered, how confident.
DERIVE GET VENDOR FOR FILE "inv-0923.pdf" → Acme Corp · derived method: letterhead extraction + vendor list match evidence: section 1, 3 prior invoices · confidence .91
Security
The boundary is the product’s shape, not a feature on it.
No client holds a source credential. The librarian holds the connections, reads the rows, joins and derives inside, and only governed results cross out. Each identity, a person, an agent or an application, is granted a scope when it is admitted, declared alongside the library’s purpose; every change the team proposes is graded against those scopes before it ships.
Refusal is structured, never silent. An agent that asks beyond its scope gets
scope_denied with what it may ask instead; a result narrowed by scope says so in its envelope.
Agents declare their intent with the request (IN CONTEXT) rather than having it sensed from
headers or location, which the specification prohibits. The same grammar that forces an agent to
commit to meaning is the grammar that bounds what it can reach.
Your manba team
Who keeps the library alive, and how.
The team is organized by what it keeps true: meaning, the model, the sources and the plant, change and its proof, signals and governance. The desk is the service as consumers meet it. Every role acts through the language, as a proposal; every proposal is graded by the benchmark; every step is an entry in one open ledger, which is also the only channel the roles have to each other and to you. Roles run at one of three autonomy tiers, self-publish, review or approve, set per library, and anything beyond a role’s tier becomes an action item for the owner.
- Retrieval
- Analysis
- Dialog
- Domain steward
- Grammar steward
- Context editor
- Model builder
- Reconciliation
- Provenance auditor
- Invariant keeper
- Source steward
- Upstream liaison
- Storage engineer
- Runtime operator
- Surface keeper
- Access steward
- Epoch steward
- Eval keeper
- Documentarian
- Triager
- Governance warden
The benchmark grades against ground truth the library did not write: the figures a publisher printed, the examples the owner confirmed, the difference between two versions. Cases the engine authored for itself never count toward its own score. Every version is deterministic: same question, same version, same answer; and a version is a self-contained bundle that can be copied, served elsewhere or carried offline and still pass its own benchmark.
Lenses
A lens is a playbook.
A substrate is raw material mounted once: a Drive, a database, an archive. A lens is a declared interest over it: what to extract, what the words mean here, which entities and fields matter, what to expect to be asked, what counts as proof, and who stewards it. Many lenses sit over one substrate, added at any time, each with its own benchmark. “Tell it you care about invoices” is adding a lens.
Because a lens is a procedure and not a description, it travels: an invoices lens written over one Drive runs over another with its declared facts swapped. And because the model is the artifact, a version of a library travels too: replicated near the people who ask, embedded in another application, or carried fully offline, an almanac on a phone in a field with no signal, answering from the model with every answer carrying its source and vintage. designed; the first offline bundle is in build
Future-proof
Smarter models make the librarian cheaper, not unnecessary.
The question comes up: once models are smart enough, why a librarian? Because capability does not dissolve access. A smarter agent still does not hold your credentials, your scope, your consent or your contracts, and it still does not get to declare what your words mean. The more capable the agent, the more the boundary matters. Meaning still needs an owner, and what was asked and answered still needs a record. None of these are model-capability problems, so better models do not remove them.
The librarian is also built to be the layer itself: no large model on the retrieval path, small task experts pinned per version and able to run where the data is, a compiled fast path for answers and a slow path for analysis, everything deterministic at a version. The thought experiment we hold ourselves to: could this replace the upper half of a modern file system, over a durable store, with lenses and native agent support as the bonus? The answer is yes, and it is testable at demo scale.
Build it with us
Engineer, researcher, domain steward, investor.
What is live, what is in build and what is next are on the landing page and in the deck, stated plainly. If you want to build the librarian, steward a public library, or back the work, tell us which, and what you would bring.