Write effective AGENTS.md files for AI coding agents.
SkillScore95Maintained
Automatic
◆AI Engineer pack
Last verified 8/18/2026
What it changes
Passed 20 of 21 test cases with the skill, and 9 of 21 without it.
Without skill41%
With skill95%
Checks it passed that the model alone missed
Recommends committing the updated agent context file to git.
Includes positive and negative code snippets in the code style section.
Formats operational boundaries using ALWAYS, ASK FIRST, and NEVER tiers.
and 15 more in the full report
12 fixed9 passed either way1 still failing0 broke
Pass-rate lift
+55 pp
Tokens
+105%
Agent turns
0%
Response time
-41%
Model gemini-3.6-flashMeasured 8/18/2026v121 of 22 cases passed with skill · 21 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 12 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 12
Prompt
I want to document code style conventions for AI assistants in our Next.js codebase. The primary pattern is using our custom `retry` utility instead of `setTimeout` for async polling in test assertions. Please draft the Code Style section for our agent prompt file.
What was checked, without and with the skill
Checked
Without skill
With skill
Includes a positive code snippet labeled GOOD demonstrating the custom retry utility.
Passed
Passed
Includes a negative code snippet labeled AVOID demonstrating the setTimeout anti-pattern.
Missed
Passed
case-06 · gemini-3.6-flash · 8/18/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md391 linessingle file
AGENTS.md Authoring Guide (Mark)
Goal: Write effective, high-signal-to-noise AGENTS.md files that outperform skills-based approaches (100% vs 79% pass rate based on Vercel research).
When to Use This Skill
Creating a new AGENTS.md file
Updating an existing AGENTS.md
Optimizing agent context for better performance
Converting from skills-based approach to AGENTS.md