[lym953]

Problem

Coding agents and review bots in this repository have no guidance on PR quality. The only instruction file is .github/copilot-instructions.md, and it covers only security.

On #169, several rounds of bot review did not report problems that a human review found later:

• The PR had about 310 lines of core code and about 1,490 lines of tests.
• Many tests checked cases that one table test already covered.
• A test checked a setting that no code reads.
• A new setting differed from the setting that the Lambda Extension uses for the same shared sampler.

This PR

• Adds AGENTS.md with rules for code style, settings, tests, PR size and reviews. Four rules come from the AGENTS.md file of the Lambda Extension:

  • the 300-line limit for core code
  • no defensive checks without a reason
  • short comments
  • a PR description that agrees with the code

  The other rules come from the review of [Traces] Add error sampling with opt-in tracer-drop rescue #169.

• Removes /AGENTS.md from .gitignore, so that the file can be committed. /CLAUDE.md stays in .gitignore, so that personal files stay local.

Testing

This PR changes only documentation. I did not run a bot review with the new file.

Open questions

• Does Copilot code review read AGENTS.md? If it does not, we can copy the review rules into .github/copilot-instructions.md.
• A user of Claude Code who has a local CLAUDE.md can add the line @AGENTS.md to it, to load these rules. The Lambda Extension commits a CLAUDE.md with that line. Do we want the same here? That change removes /CLAUDE.md from .gitignore, and a pull fails for each person who has an untracked CLAUDE.md.
• Some people possibly have a local, untracked AGENTS.md. After this PR merges, a pull fails for them until they move that file.

🤖 Generated with Claude Code