setup-gitignore

A guide for creating or updating a repository's .gitignore file, which tells Git which generated, temporary, or local files not to track. It combines detected project types, tool and editor patterns, and confirmed untracked files.

In plain words
What is it for?
Use it to set up or repair a project's .gitignore when untracked files keep appearing.
Why use it?
It helps stop unwanted files from repeatedly appearing in Git status while preserving the repository's existing rules.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/outlinedriven/odin-codex-plugin/setup-gitignore
Any agent
npx skills add OutlineDriven/odin-codex-plugin --skill setup-gitignore
Clone the repo
git clone --depth 1 https://github.com/OutlineDriven/odin-codex-plugin

Made for: Claude Code, Codex.

Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 760 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00064 $0.00760
Opus 5 $0.00032 $0.00380
Sonnet 5 $0.00013 $0.00152
Haiku 4.5 $0.00006 $0.00076

Measured 2d ago against content hash f52a64215f22, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

setup-gitignore scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/compose-gitignore.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

skills/setup-gitignore/SKILL.md · 88 lines

How it starts

The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Initialize or idempotently revise the current repo's .gitignore — never the global excludesfile.

Scope

Per-repo only. Never read or write ~/.gitignore, ~/.config/git/ignore, or run git config --global. The user's global excludesfile handles cross-machine noise; this skill handles language/tool specifics for the current repo.

Sources composed (in order)

  1. gitignore.io — templates keyed by detected language/framework (requires network)
  2. AI tooling — bundled patterns from references/AI-TOOLING.md
  3. IDE / editor — bundled patterns from references/IDE-EDITOR.md
  4. Empirical — untracked paths from git status, confirmed interactively

Workflow

1. Detect repo root

git rev-parse --show-toplevel

Abort with a clear error if not inside a git repo.

2. Detect languages

Read references/LANGUAGE-DETECTION.md for the manifest → gitignore.io key table. Scan manifests:

fd --max-depth 2 -t f

Match filenames against the detection table; build a comma-separated key list (e.g., rust,node,typescript). If no manifests detected, use an empty key list (bundled blocks still apply).

3. Snapshot existing .gitignore

If .gitignore exists, snapshot it before any modification:

cp .gitignore /tmp/gitignore-snapshot-$(date +%s).bak

4. Surface empirical noise

git status -s -uall | rg '^\?\?' | rg -v '^\?\? \.gitignore'

Cluster untracked paths by top-level directory or extension. Present clusters to the user and wait for explicit confirmation. Do not add any empirical pattern without confirmation.

5. Compose

Run scripts/compose-gitignore.sh <csv> to fetch and merge gitignore.io templates. If the network call fails, tell the user and ask whether to continue with bundled-only mode.

Append the bundled blocks after the API output in order:

# === AI TOOLING ===
<contents of references/AI-TOOLING.md>

# === IDE / EDITOR ===
<contents of references/IDE-EDITOR.md>

# === EMPIRICAL ===
<user-confirmed patterns, one per line>

Read the full file on GitHub · 88 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 88 lines · 64 tokens per session scan A f52a64215f22

Subscribe to this mod's changes

setup-gitignore is a skill published in the GitHub repository OutlineDriven/odin-codex-plugin (15 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 64 tokens to every session and 760 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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