Squirrel — Full-Cycle Software Development Skill

Overview

Squirrel is a full-cycle AI coding skill that works across 9 AI coding agents. It auto-detects project state (greenfield, in-progress, or mature) and adapts its 8-phase engineering pipeline accordingly. Instead of a one-size-fits-all workflow, it figures out where the project actually is and jumps in at exactly the right point.

When to Use This Skill

• Use when starting a new project from scratch (greenfield)
• Use when improving an existing codebase (in-progress or mature)
• Use when fixing bugs, adding features, or refactoring
• Use when adding tests, linting, or CI/CD to a project
• Use when writing production-grade documentation
• Use when the user says "build me", "fix this", "squirrel this project", or any multi-step development task

How It Works

Step 0: Detect Mode

Squirrel classifies the project directory:

Signal	Mode	Entry Point
Empty directory	Greenfield	All 8 phases from scratch
Source files, no tests/docs	In-Progress	Audit first, then improve
Source + tests + CI + README	Mature	Targeted improvements
"fix this bug / add feature"	Targeted	Scoped work only

The 8-Phase Pipeline

1. Discover — Understand the project (audit existing code or gather requirements)
2. Plan — Concrete task list with dependencies and done-criteria
3. Build — Write or modify code (parallel sub-agents when supported)
4. Test — Run existing tests, write new ones, 70%+ coverage target
5. Bug Hunt — Static analysis + manual review
6. Polish — Lint, format, type check, remove dead code
7. Document — README + inline docs (update existing, don't overwrite)
8. Ship — Final checklist: tests green, no secrets, CI configured

Failure Recovery (3-Strike Rule)

1. Strike 1: Fix the specific error. Run tests. Move on.
2. Strike 2: Re-read the code. Try a different approach.
3. Strike 3: STOP. Revert. Document what failed. Ask the user.

Examples

Example 1: Build a REST API

> build me a REST API for a todo app with TypeScript and Express

Squirrel auto-detects greenfield mode and runs all 8 phases.

Example 2: Fix a bug

> fix this bug in src/auth/login.py

Squirrel enters targeted mode — abbreviated audit, scoped fix, verify.

Example 3: Improve existing project

> squirrel this project — add tests, fix lint errors, write README

Squirrel audits the existing codebase, then applies phases 4-8.

Best Practices

• Respects existing code — matches naming conventions, test framework, import style, and architecture
• Reads 2-3 similar files before writing a new one
• Never suppresses type errors with as any or @ts-ignore
• Never deletes failing tests to "pass"
• Never leaves code in a broken state

Platform Compatibility

Squirrel works on: Claude Code, Codex, Cursor, Antigravity, Gemini CLI, GitHub Copilot, Windsurf, OpenCode, Aider (9 total).

Install with:

# Universal installer
npx skills add flyingsquirrel0419/squirrel-skill

Limitations

• Does not replace environment-specific validation or expert review
• CI/CD templates are starting points, not drop-in guarantees
• Parallel sub-agent execution depends on platform support

Related Skills

• @brainstorming - For planning before implementation
• @test-driven-development - For TDD-oriented workflows
• @systematic-debugging - For methodical problem-solving