# Init > Use when a repository's AGENTS.md is missing, too long, generic or stale. 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. ## Facts - Type: Agent skill - Discipline: Engineering - Author: Matteo Collina (https://github.com/mcollina) - Upstream: https://github.com/mcollina/skills/blob/main/skills/init/SKILL.md - Source file: https://raw.githubusercontent.com/mcollina/skills/main/skills/init/SKILL.md (3765 bytes, sha256:4b8133592b9b302dfeb079d8dd778e61a8e36b370490448c70f0a58a9a4b6c04) - Licence: MIT - Upstream copy last changed: 2026-09-17 - Status: listed, not yet ruled on by the curator ## Use it I want to use the Init skill by Matteo Collina. This is what it does, in the author's own words: 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. Download the whole folder at https://github.com/mcollina/skills/tree/main/skills/init, SKILL.md and every file beside it, into your skills directory: ~/.claude/skills/init/ for Claude Code, ~/.agents/skills/init/ for Codex, ~/.cursor/skills/init/ for Cursor. Get it from the author's repo, not from startupskills.dev. Then tell me the path you installed it to and how to invoke it. Nothing here is vendored: install from the author's repo, not from this site. A verbatim copy of the author's file follows for reading, under the licence reproduced after it; the current file is in the author's repo. ## Links - Page: https://startupskills.dev/mcollina/init - Author: https://startupskills.dev/mcollina - Index: https://startupskills.dev/llms.txt ## The file itself --- name: init description: 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. metadata: tags: initialization, agents, context-engineering, agents-md, maintenance --- ## 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: 1. **Non-discoverable** from repository files alone 2. **Operationally significant** (changes commands, outcomes, or safety) 3. **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) If `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: 1. Prefer fixing the root cause in code/tooling (lint rule, test, script, structure) 2. Keep only the minimum instruction needed until the root cause is solved 3. 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. ## Licence of the file above The file above is https://raw.githubusercontent.com/mcollina/skills/main/skills/init/SKILL.md, by Matteo Collina, reproduced without changes. - Source: https://github.com/mcollina/skills/blob/main/skills/init/SKILL.md - Copyright: Copyright (c) 2026 Matteo Collina - Licence: MIT, https://raw.githubusercontent.com/mcollina/skills/main/LICENSE The repo's licence file, verbatim from https://raw.githubusercontent.com/mcollina/skills/main/LICENSE: MIT License Copyright (c) 2026 Matteo Collina Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.