Files
rust-analyzer/AGENTS.md
Wilfred Hughes ef3ab9a73b internal: Define rules for LLMs
rust-analyzer allows AI usage (see #21314), but requires contributors
to declare usage. This adds a rule file that improves LLM output
quality and instructs the LLM to declare usage in commit messages.

I've written the rules in CLAUDE.md, but also symlinked it to
AGENTS.md so other LLM tools pick it up.

## Rules file contents

(1) Instructions for both humans and AIs to declare AI usage.

(2) Relevant commands for testing, linting and codegen.

Note that I deliberately didn't include an overview of the project
structure on a folder-by-folder basis. This can go stale, and there's
some evidence that project structure can hurt LLM output quality
overall.

See the following paper:

> Evaluating AGENTS.md:
> Are Repository-Level Context Files Helpful for Coding Agents?
> https://arxiv.org/pdf/2602.11988

## Testing

I exercised this change with the following contrived prompt. Note that
in practice rust-analyzer is hitting review scaling limits for new
code actions, but it was easy to test end-to-end.

> Add a new code action that replaces the content of a string literal
> with the text "banana".
...
> commit it

This produced a functional code action with both Codex and Claude, and
in both cases the commit message mentioned that it was AI
generated. Example commit message:

    Add "Replace string with banana" code action

    Add a new assist that replaces a string literal's content with "banana"
    when the cursor is on a STRING token.

    AI: Generated with Claude Code (claude-opus-4-6).

I confirmed that the code action worked by testing a rust-analyzer
build in Emacs, and also confirmed that the generated tests looked
sensible.

## AI Usage Disclosures

I wrote the first draft of the rules file with Opus 4.6, manually
reviewed everything.
2026-03-03 11:22:58 +00:00

Symbolic link
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