# Answers from the installed build

Half of a well-documented library's exported names are mentioned nowhere in its own
documentation. Measured against two projects that document themselves well, hono's site
covers 51% of what hono exports and zod's covers 27%. Every one of those uncovered names is
declared in the package sitting in `node_modules`.

So `docspack sync` indexes that too. Alongside the documentation packages, it reads each
installed library's own type declarations and records one entry per exported name, carrying
the import a caller writes and the declaration as the installed build states it.

```
+ @acme/docspack@1.4.0  128 chunks  indexed
+ hono@4.13.3  272 chunks  indexed (declarations)
```

This is what a documentation site cannot serve, because the site is not the artifact, and
what `llms.txt` cannot serve for the same reason. docspack is already running in the
directory where the answer is.

## Declarations are looked up by name, never ranked

A library exports far more names than its documentation has pages. Ranking declarations
against prose would answer every question with type machinery, so they are not in the
ranking at all: a declaration reaches an answer only when the question names it exactly.

Matching is case-sensitive. Someone asking about an API writes it as it is spelled, because
they read it in a stack trace or an editor. Matching loosely would let "how do I send data"
pin a type called `Data` ahead of the page that answers the question.

## Saying what the documentation does not cover

A ranker always returns its best matches, and "best" is not "relevant". Ask about a name no
documentation mentions and the old answer was three unrelated passages, formatted exactly
like a correct answer, with nothing to say the subject was never covered.

Now the answer leads with the declaration and ends with the difference:

```text
## hono@4.13.3/ValidationTargets
Source: hono@4.13.3 — declared in dist/types/types.d.ts, read from the installed package

# ValidationTargets

Declared by `hono/types`. This is the installed build's own declaration, not prose.

    import { ValidationTargets } from "hono/types";

    export type ValidationTargets = { … };

---

NOTE: `ValidationTargets` is exported by the installed library but mentioned in no
documentation package here. The declaration above is the installed build's own, not prose
anyone wrote.
```

A question that names no symbol — "how do I stream a response" — has no name to be absent,
so nothing changes for it. This closes the half that can be checked mechanically.

## Turning it off

```bash
npx docspack sync --no-artifacts
```

Declarations are read from packages this project depends on directly, and only from names an
entry point in the `exports` map actually publishes. A package that ships no type
declarations is skipped without comment: most of a dependency tree is not what anybody asks
questions about.

## What changed between two versions

The store is global, so a version indexed for one project on this machine is available to
every other. `docspack changed` compares two of them:

```bash
npx docspack changed hono
```

```
hono 3.12.12 → 4.13.3  246 added, 3 removed

gone  COMPOSED_HANDLER, UndefinedIfHavingQuestion, childrenToString

new   ALBProcessor, Accept, AddedSSGDataRequest … and 226 more (--json for all)

237 new names that no documentation package here mentions:
…
```

Upgrades are overwhelmingly additive. The gap between what a model remembers and what is
installed is mostly **things that did not exist yet**, not things that broke — and the
useful report is what exists now that an older release did not have. Nothing is fetched:
both versions come from the local index, and a version that is not indexed is an error
saying so rather than a network request.

## Coverage

The same comparison, pointed at a documentation package instead of a version:

```bash
npx docspack list --coverage
```

```
@acme/docspack@1.4.0  128 chunks  indexed
  documents 189/367 (51%) of acme's exports
  missing: ValidationTargets, NotFoundHandler, ErrorHandler, …
```

`docspack doctor` reports the same number as a note. It is never a failure and `--strict`
never promotes it: a page listing every export and explaining none would score full marks,
so this is a number for an author to read rather than a gate. A package documenting a
command line rather than a library API will score near zero and be perfectly correct — the
note's own suggested fix says so.