GeminiIgnore FinOps Setup & Optimization

Overview

A skill to construct, refine, and maintain high-performance .geminiignore files across diverse tech stacks. By filtering out machine-generated code, heavy logs, package locks, and binary assets, this skill optimizes the AI agent's context window, accelerates processing speed, and reduces token consumption costs (FinOps).

When to Use This Skill

• Use when initializing a new repository or workspace for pair-programming with AI agents.
• Use when the AI context window is reaching its limits or when billing optimization (FinOps) is a priority.
• Use when the AI agent is accidentally reading build outputs, lock files, databases, or binary media.

How It Works

Step 1: Analyze the Workspace Tech Stack

Detect the languages, frameworks, and dependency managers present in the project (e.g., Node.js, Python, PHP, Dart/Flutter, Rust).

Step 2: Initialize or Update the .geminiignore File

Create a .geminiignore file at the root of the active workspace. If one already exists, review it to add missing categories.

Step 3: Implement the 7 Core Rules

Add rules divided into the following categories to filter out unnecessary machine noise while keeping human-written code visible:

1. System & Editor Noise: Block OS temp files (.DS_Store, Thumbs.db) and user-specific IDE caches (.idea/, .vscode/*, Xcode user data).
2. Dependency Folders & Lock Files: Ignore third-party package directories (node_modules/, vendor/) and giant machine-generated lock files (package-lock.json, yarn.lock, Cargo.lock, composer.lock).
3. Build & Target Output: Block compiled folders (dist/, build/, .next/, .nuxt/).
4. Caches & Tool Metadata: Block compiler caches (.tsbuildinfo, .vite/, .pytest_cache/, .eslintcache).
5. Binary & Rich Assets: Block media types (*.png, *.pdf, *.mp4, *.woff2) to prevent triggering expensive vision/multimodal tokens.
6. Local Databases & Logs: Block log files (*.log) and SQL dumps or local SQLite DBs (*.sqlite, *.db).
7. Compiled Binaries & Mobile Builds: Block mobile package files (*.apk, *.ipa) and compiled binaries (*.class, *.pyc, *.dll).

Step 4: Validate Exclusions

Verify that the AI can still see critical configuration blueprints (like .env.example, package.json, composer.json, pyproject.toml) but ignores the actual .env files and compilation artifacts.

Examples

Example 1: Standard Universal .geminiignore Template

Here is a recommended baseline configuration for a multi-language project:

ini
# ==============================================================================
# .geminiignore - BASELINE DE FINOPS E ARQUITETURA
# ==============================================================================

# 1. SISTEMA OPERACIONAL E IDEs
.DS_Store
Thumbs.db
Desktop.ini
$RECYCLE.BIN/
.vscode/*
!.vscode/settings.json
!.vscode/tasks.json
!.vscode/launch.json
.idea/
*.iml
.gradle/
local.properties
.history/

# 2. DEPENDÊNCIAS (ECONOMIA DE TOKENS EM LOCK FILES)
node_modules/
package-lock.json
yarn.lock
pnpm-lock.yaml
vendor/
composer.lock
venv/
.venv/
env/
.env
.env.*
!.env.example
poetry.lock
Cargo.lock
pubspec.lock

# 3. BUILDS E EXPORTAÇÕES
dist/
build/
out/
target/
.next/
.nuxt/
.output/
bin/
obj/

# 4. CACHES DE FRAMEWORKS
.vite/
.parcel-cache/
.eslintcache
.babel-cache/
.tsbuildinfo
.turbo/
.pytest_cache/
.ruff_cache/
storage/framework/
storage/logs/

# 5. ASSETS BINÁRIOS E MULTIMÍDIA EXTREMOS
*.png
*.jpg
*.jpeg
*.gif
*.webp
*.svg
*.ico
*.psd
*.fig
*.pdf
*.zip
*.tar.gz
*.woff
*.woff2
*.ttf

# 6. BANCOS DE DADOS E LOGS
*.log
*.db
*.sqlite
*.sqlite3
*.sql
*.sql.gz

# 7. ARQUIVOS COMPILADOS
*.apk
*.aab
*.ipa
*.jar
*.class
*.pyc
__pycache__/
*.so
*.dylib
*.dll
*.exe
*.js.map
*.css.map

Best Practices

• ✅ Ignore dependency lock files: Standard lock files (e.g., package-lock.json, yarn.lock) contain thousands of lines of redundant package resolution trees. Ignoring them is the single largest FinOps win.
• ✅ Keep configurations visible: Ensure manifests like package.json, composer.json, Cargo.toml, and pyproject.toml are NEVER ignored, as the AI needs them to understand dependencies.
• ✅ Whitelist config examples: Use rules like !.env.example alongside .env ignores so the AI understands configuration structure without exposing credentials.
• ❌ Do not ignore source code: Avoid overly broad folder patterns like lib/ or app/ if they contain primary source code. Be specific (e.g., block vendor/bundle/ but not your actual code).

Limitations

• A .geminiignore file only affects AI tools parsing the workspace; it does not replace .gitignore for Git repository hosting.
• Patterns must be formatted correctly according to gitignore-style globbing to avoid accidentally ignoring source files.

Related Skills

• @context-optimization - Broad tactics for context window management.
• @clean-code - Architectural practices for clean, human-readable codebases.