What agents should know before contributing
biomejs/biome
A toolchain for web projects, aimed to provide functionalities to maintain them. Biome offers formatter and linter, usable via CLI and LSP.
Read by Bluet from 3 files written for agents and 300 merged pull requests on 2026-09-24. Not reviewed by the maintainers.
Rules its files tell agents (12)
- AGENTS.md
mustPreserve .github/PULL_REQUEST_TEMPLATE.md; never replace or bypass it.
- AGENTS.md
mustNever revert or rewrite changes you did not make.
Preserve unrelated worktree changes. Never revert or rewrite changes you did not make.
- AGENTS.md
shouldDo not narrate change history or address reviewers.
- AGENTS.md
shouldDo not write PR descriptions or contributor communication.
Do not write PR descriptions or contributor communication. CONTRIBUTING.md requires the contributor to author that prose.
- AGENTS.md
shouldDo not include suspected defects, implementation hints, prior findings, or expected outcomes.
Provide only the review scope and intended business requirements. Do not include suspected defects, implementation hints, prior findings, or expected outcomes.
- AGENTS.md
shouldUser-facing behavior requires a changeset; internal refactors, tests, CI, and documentation-only changes do no…
Before opening a PR, explicitly confirm whether the change is user-facing. User-facing behavior requires a changeset; internal refactors, tests, CI, and documentation-only changes do not.
- CLAUDE.md
shouldInternal changes don't need changesets.
Our changesets should be about user-facing changes. Internal changes don't need changesets. For example, if you refactored some code, but the user-facing behavior didn't change, you don't need a changeset.
- CLAUDE.md
shouldUsing merge commit is recommended here, do not use squash merge as it removes the commit history.
[ ] Merge next to main. Using merge commit is recommended here, do not use squash merge as it removes the commit history.
- AGENTS.md
shouldDo not claim a Biome function, module, behavior, or convention exists without an exact file and line, a source…
Do not claim a Biome function, module, behavior, or convention exists without an exact file and line, a source excerpt, or a reproducible command.
- AGENTS.md
shouldDo not use emojis in source, comments, rustdoc, diagnostics, tests, snapshots, commits, issues, PR communicati…
Do not use emojis in source, comments, rustdoc, diagnostics, tests, snapshots, commits, issues, PR communication, or agent output. The PR-title marker above is the only exception.
- CLAUDE.md
shouldTo create a changeset, use the following command (don't create it manually):
If the PR you're about to open is a bugfix/feature visible to users of the Biome toolchain or of the published Biome crates, you are encouraged to provide a changeset . To create a changeset, use the following command (don't create it manually):
- CLAUDE.md
shouldPlease do not use AI to write pull request descriptions or contributor communication for this project.
Please do not use AI to write pull request descriptions or contributor communication for this project. Maintainers have limited review bandwidth, and unnecessarily long or low-signal explanations can slow down the review process.