Refactor code so invariants are enforced by the type system instead of repeated runtime checks. Parse and validate at trust boundaries, then make invalid internal states impossible to construct. Use when reviewing or refactoring code with boolean lifecycle flags, optional fields that must appear together, "must call X before Y" comments, repeated validation of the same value, or field combinations that should be contradictory. Also triggers on requests like "make illegal states unrepresentable", "parse, don't validate", or "strengthen these types".
EnglishCross-model code review using a second agent, tool, or read-only CLI fallback. This skill should be used when someone asks to rubber duck a change, get a second opinion, or run an independent review focused on correctness, future-proofing, and design quality.
English
AGENT SKILLS ATLASIncludes No Invalid States and Rubber Duck Review.
Claude Code
Codex
Cursor
GitHub Copilot
Gemini CLISupported by the Atlas install prompt. Skill-specific requirements vary.
Pack stats
What’s included
No Invalid States
Refactor code so invariants are enforced by the type system instead of repeated runtime checks. Parse and validate at trust boundaries, then make invalid internal states impossible to construct. Use when reviewing or refactoring code with boolean lifecycle flags, optional fields that must appear together, "must call X before Y" comments, repeated validation of the same value, or field combinations that should be contradictory. Also triggers on requests like "make illegal states unrepresentable", "parse, don't validate", or "strengthen these types".
Rubber Duck Review
Cross-model code review using a second agent, tool, or read-only CLI fallback. This skill should be used when someone asks to rubber duck a change, get a second opinion, or run an independent review focused on correctness, future-proofing, and design quality.
Quick start
- Choose your skills. Select individual skills above, or choose the entire pack.
- Copy the install prompt. Use Copy install prompt above the list.
- Send it to your agent. Paste into your coding agent’s chat. Your agent reviews the source and guides the setup.
Try it with your agent
After installation, start with a request like:
Use the No Invalid States skill to help with my task.
Ask me for the context you need before getting started.Requirements & license
- A coding agent that can access your project files and install skills.
- Your agent checks each skill’s instructions, dependencies, and permissions during setup.
- Reported license for the skills shown: MIT. The author’s terms apply.