llms.txt

Alongside the rendered MDX, docsgen can emit an llms.txt file: a single plain-text document containing your entire public API, formatted for an LLM to ingest in one shot. Drop it into an agent and it has your library’s surface as context.

Enabling it

Pass the flag:

docsgen --llms-txt

or set it in config:

llms_txt:
  enabled: true
  # output: "./public"   # for Astro projects, llms.txt belongs in public/

By default the file is written next to your MDX output. Use --llms-txt-output <dir> (or llms_txt.output) to redirect it — for an Astro site, public/ so it’s served at /llms.txt.

What’s in it

The bundle leads with a header built from your config — title, tagline, and a metadata line:

# net

> Async non-blocking socket library

**Version:** 1.0.0 | **License:** MIT | **Authors:** CodeXX Team

---

Then one section per public symbol, in qualified-name order, each rendered in plain Markdown (no MDX escaping):

## net::Socket

*class*

Async, non-blocking socket with an RAII lifetime. ...

**Parameters:**
- `proto` -- Transport protocol.

**Returns:** Handle for cancellation.

**Notes:**
- Does not support multi-homed binding in this version.

**See also:** Endpoint, AsyncHandle

---

The same public-API filter and exclude_namespaces list that govern the MDX output apply here, so the bundle stays in sync with the rendered site.

The @llms-only tag

Some symbols are worth giving an agent but not worth a page on the site — internal-but-documented helpers, agent hints, fast paths. Tag the comment:

/// @llms-only
/// Internal fast encoder used by the generated bindings.
void __fast_encode(...);

@llms-only symbols are skipped during MDX generation but still included in llms.txt (as long as they pass the public-API filter). It’s the one-way valve: visible to machines, hidden from the rendered docs.

This is the docsgen tool feature — it generates llms.txt for your C++ library. Separately, this very documentation site publishes its own /llms-full.txt via the starlight-llms-txt plugin. Same idea, two layers: docs about docsgen, and the API docs docsgen produces.

Why ship it

A rendered HTML site is for humans; llms.txt is for the agents your users increasingly code alongside. One file, deterministic, regenerated on every build — so the model’s view of your API never drifts from the source.