Skills init

Creates, updates, or optimizes an AGENTS.md file for a repository with minimal, high-signal instructions covering non-discoverable coding conventions, tooling quirks, workflow preferences, and project-specific rules that agents cannot infer from reading the codebase. Use when setting up agent instructions or Claude configuration for a new repository, when an existing AGENTS.md is too long, generic, or stale, when agents repeatedly make avoidable mistakes, or when repository workflows have changed and the agent configuration needs pruning. Applies a discoverability filter—omitting anything Claude can learn from README, code, config, or directory structure—and a quality gate to verify each line remains accurate and operationally significant.

install

source · Clone the upstream repo

git clone https://github.com/mcollina/skills

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/mcollina/skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/init" ~/.claude/skills/mcollina-skills-init && rm -rf "$T"

manifest: skills/init/SKILL.md

source content

When to use

Use this skill when creating or updating

AGENTS.md

for a repository.

Use it especially when:

the current
```
AGENTS.md
```
is long, generic, or stale
agents repeatedly make the same avoidable mistakes
repository workflows changed and agent guidance needs pruning

Instructions

Treat

AGENTS.md

as a living list of non-discoverable landmines and workflow gotchas, not a codebase overview.

Core rule: discoverability filter

Before adding any line, ask:

Can an agent discover this by reading the repo (
README
, code, config, scripts, directory tree)?

If yes: do not include it in
```
AGENTS.md
```
.
If no, and it materially affects task success/cost/safety: include it.

What earns a line

Include only guidance that is:

Non-discoverable from repository files alone
Operationally significant (changes commands, outcomes, or safety)
Actionable (specific enough to execute)

Typical examples:

Non-standard tooling choices (e.g. use
```
uv
```
instead of
```
pip
```
)
Command caveats (e.g. tests must run with
```
--no-cache
```
due to fixture behavior)
Hidden constraints/landmines (deprecated directories still imported in production)
Critical local conventions that are not encoded in lint/tests/config

What to remove or avoid

Do not include:

Tech stack summaries
Directory structure overviews
Architecture descriptions agents can infer from code
Generic best-practice advice
Rules already enforced by tooling (linters, typecheck, tests, CI)
Mandatory boilerplate headers unless the repo explicitly requires one

Recommended structure

Prefer short, high-signal sections such as:

```
Scope & routing
```
(which areas need separate/module-local AGENTS files)
```
Non-discoverable commands
```
```
Landmines / do-not-touch areas
```
```
Task-specific constraints
```

For large repos, recommend hierarchical AGENTS.md files near relevant modules instead of one monolithic root file.

Source files to check first

Existing
```
AGENTS.md
```
```
README.md
```
```
PROJECT.md
```
(if present)
Cursor rules (
```
.cursor/rules/
```
or
```
.cursorrules
```
)
Copilot instructions (
```
.github/copilot-instructions.md
```
)
```
GEMINI.md
```
CI/workflow files and package manager config (for command/tooling mismatches)

AGENTS.md

exists, improve it incrementally instead of replacing it blindly.

Maintenance mindset

AGENTS.md

is temporary guidance, not permanent configuration.

When recurring issues appear:

Prefer fixing the root cause in code/tooling (lint rule, test, script, structure)
Keep only the minimum instruction needed until the root cause is solved
Prune stale instructions aggressively

Quality gate before finalizing

For each line in

AGENTS.md

, verify:

Is it non-discoverable?
Is it still accurate today?
Does it materially reduce mistakes/cost/time?

Delete any line that fails one of these checks.