Install
npx skills add https://github.com/mattpocock/skills --skill triageWriting Agent Briefs
An agent brief is a structured comment posted on a GitHub issue or PR when it moves to ready-for-agent. It is the authoritative specification that an AFK agent will work from. The original body and discussion are context: the agent brief is the contract.
The brief states what the agent should do, which stretches to both surfaces: for an issue, that's building the change from nothing; for a PR, it's what's left to do to the existing diff: finish it, close gaps, address review points. Same principles either way; the PR example below shows the difference.
Principles
Durability over precision
The issue may sit in ready-for-agent for days or weeks. The codebase will change in the meantime. Write the brief so it stays useful even as files are renamed, moved, or refactored.
- Do describe interfaces, types, and behavioral contracts
- Do name specific types, function signatures, or config shapes that the agent should look for or modify
- Don't reference file paths: they go stale
- Don't reference line numbers
- Don't assume the current implementation structure will remain the same
Behavioral, not procedural
Describe what the system should do, not how to implement it. The agent will explore the codebase fresh and make its own implementation decisions.
- Good: "The
SkillConfigtype should accept an optionalschedulefield of typeCronExpression" - Bad: "Open src/types/skill.ts and add a schedule field on line 42"
- Good: "When a user runs
/triagewith no arguments, they should see a summary of issues needing attention" - Bad: "Add a switch statement in the main handler function"
Complete acceptance criteria
The agent needs to know when it's done. Every agent brief must have concrete, testable acceptance criteria. Each criterion should be independently verifiable.
- Good: "Running
gh issue list --label needs-triagereturns issues that have been through initial classification" - Bad: "Triage should work correctly"
Explicit scope boundaries
State what is out of scope. This prevents the agent from gold-plating or making assumptions about adjacent features.
Template
Examples
Good agent brief (bug)
Good agent brief (enhancement)
Good agent brief (PR)
For a PR, "Current behavior" describes the state of the diff, and the brief asks the agent to finish or fix it rather than build from scratch.
Bad agent brief
This is bad because:
- No category
- Vague description ("the triage thing is broken")
- References file paths and line numbers that will go stale
- No acceptance criteria
- No scope boundaries
- No description of current vs desired behavior