llms.txt

Serve a machine-readable route summary at /__rapina/llms.txt for AI agents

Rapina can serve a llms.txt document at /__rapina/llms.txt. The document is a single Markdown file that lists every route your app exposes — methods, paths, request schemas, response schemas, and error codes — in a format AI agents can read in one fetch without scraping HTML or consulting a verbose OpenAPI spec.

The document is generated once at startup from the same route metadata that powers OpenAPI, so it is always in sync with your handlers.

Enabling llms.txt

llms.txt is on by default in debug builds and off in release builds. No configuration needed for local development.

To control it explicitly:

use rapina::prelude::*;

#[tokio::main]
async fn main() -> std::io::Result<()> {
    Rapina::new()
        .enable_llms_txt()   // force on (e.g. in a staging build)
        .discover()
        .listen("127.0.0.1:3000")
        .await
}

To disable it:

Rapina::new()
    .disable_llms_txt()
    .discover()
    .listen("127.0.0.1:3000")
    .await

Or use .with_llms_txt(bool) for conditional logic:

Rapina::new()
    .with_llms_txt(std::env::var("EXPOSE_LLMS_TXT").is_ok())
    .discover()
    .listen("127.0.0.1:3000")
    .await

The Endpoint

GET /__rapina/llms.txt returns text/plain; charset=utf-8. The endpoint is public — it does not require authentication even when auth middleware is enabled.

If llms.txt was not enabled, the endpoint is not registered and requests return 404.

Internal /__rapina/* routes are excluded from the document. Only user-defined routes appear.

Output Format

The document follows the llms.txt convention. Everything is inlined in one file — no index/detail split. Example output for an app with a single route:

# API

Built with [Rapina](https://rapina.rs) v0.11.0.

## Routes

### POST /v1/users

Request (application/json):
{
"type": "object",
"properties": {
"email": { "type": "string" },
"name": { "type": "string" }
}
}

Response:
{
"type": "object",
"properties": {
"id": { "type": "number" },
"email": { "type": "string" }
}
}

Errors:

- 409 CONFLICT: email is already registered
- 422 VALIDATION_ERROR: request body failed validation

Request and response schemas are rendered verbatim from the same JSON Schema that powers the OpenAPI spec. Handlers that don't return Json<T> or don't accept a typed request body produce no schema block for that section.

CLI

The rapina llms export command fetches the document from your running development server and writes it to stdout or a file.

# Print to stdout
rapina llms export

# Write to file
rapina llms export -o llms.txt

See rapina llms export for the full option reference.