agents-md by getsentry

---
name: agents-md
description: This skill should be used when the user asks to "create AGENTS.md", "update AGENTS.md", "maintain agent docs", "set up CLAUDE.md", or needs to keep agent instructions concise. Enforces research-backed best practices for minimal, high-signal agent documentation.
---

# Maintaining AGENTS.md

AGENTS.md is the canonical agent-facing documentation. Keep it minimal—agents are capable and don't need hand-holding. Target under 60 lines; never exceed 100. Instruction-following quality degrades as document length increases.

## File Setup

1. Create `AGENTS.md` at project root
2. Create symlink: `ln -s AGENTS.md CLAUDE.md`

## Before Writing

Analyze the project to understand what belongs in the file:

1. **Package manager** — Check for lock files (`pnpm-lock.yaml`, `yarn.lock`, `package-lock.json`, `uv.lock`, `poetry.lock`)
2. **Linter/formatter configs** — Look for `.eslintrc`, `biome.json`, `ruff.toml`, `.prettierrc`, etc. (don't duplicate these in AGENTS.md)
3. **CI/build commands** — Check `Makefile`, `package.json` scripts, CI configs for canonical commands
4. **Monorepo indicators** — Check for `pnpm-workspace.yaml`, `nx.json`, Cargo workspace, or subdirectory `package.json` files
5. **Existing conventions** — Check for existing CONTRIBUTING.md, docs/, or README patterns

## Writing Rules

- **Headers + bullets** — No paragraphs
- **Code blocks** — For commands and templates
- **Reference, don't embed** — Point to existing docs: "See `CONTRIBUTING.md` for setup" or "Follow patterns in `src/api/routes/`"
- **No filler** — No intros, conclusions, or pleasantries
- **Trust capabilities** — Omit obvious context
- **Prefer file-scoped commands** — Per-file test/lint/typecheck commands over project-wide builds
- **Don't duplicate linters** — Code style lives in linter configs, not AGENTS.md

## Required Sections

### Package Manager
Which tool and key commands only:
```markdown
## Package Manager
Use **pnpm**: `pnpm install`, `pnpm dev`, `pnpm test`
```

### File-Scoped Commands
Per-file commands are faster and cheaper than full project builds. Always include when available:
```markdown
## File-Scoped Commands
| Task | Command |
|------|---------|
| Typecheck | `pnpm tsc --noEmit path/to/file.ts` |
| Lint | `pnpm eslint path/to/file.ts` |
| Test | `pnpm jest path/to/file.test.ts` |
```

### Commit Attribution
Always include this section. Agents should use their own identity:
```markdown
## Commit Attribution
AI commits MUST include:
```
Co-Authored-By: (the agent's name and attribution byline)
```
Example: `Co-Authored-By: Claude Sonnet 4 <noreply@example.com>`
```

### Key Conventions
Project-specific patterns agents must follow. Keep brief.

## Optional Sections

Add only if truly needed:
- API route patterns (show template, not explanation)
- CLI commands (table format)
- File naming conventions
- Project structure hints (point to critical files, flag legacy code to avoid)
- Monorepo overrides (subdirectory `AGENTS.md` files override root)

## Anti-Patterns

Omit these:
- "Welcome to..." or "This document explains..."
- "You should..." or "Remember to..."
- Linter/formatter rules already in config files (`.eslintrc`, `biome.json`, `ruff.toml`)
- Listing installed skills or plugins (agents discover these automatically)
- Full project-wide build commands when file-scoped alternatives exist
- Obvious instructions ("run tests", "write clean code")
- Explanations of why (just say what)
- Long prose paragraphs

## Example Structure

```markdown
# Agent Instructions

## Package Manager
Use **pnpm**: `pnpm install`, `pnpm dev`

## Commit Attribution
AI commits MUST include:
```
Co-Authored-By: (the agent's name and attribution byline)
```

## File-Scoped Commands
| Task | Command |
|------|---------|
| Typecheck | `pnpm tsc --noEmit path/to/file.ts` |
| Lint | `pnpm eslint path/to/file.ts` |
| Test | `pnpm jest path/to/file.test.ts` |

## API Routes
[Template code block]

## CLI
| Command | Description |
|---------|-------------|
| `pnpm cli sync` | Sync data |
```