--- title: "Superpowers Test-Driven Development: review, setup & limitations · Undominated.ai" canonical: https://undominated.ai/skills/obra-test-driven-development/ description: "Makes an observed failing behavior test the entry point for implementation and checks that assertions can detect real production mistakes." --- # Superpowers Test-Driven Development: review, setup & limitations · Undominated.ai > Makes an observed failing behavior test the entry point for implementation and checks that assertions can detect real production mistakes. [← Explore all skills](/skills/) TESTING AND RELIABILITY / Jesse Vincent / Superpowers # Superpowers Test-Driven Development Makes an observed failing behavior test the entry point for implementation and checks that assertions can detect real production mistakes. See setup guidance ↓Original source ↗ SOURCE REVIEW Reviewed 2026-09-21 Evidence 6 linked sources Publisher Jesse Vincent / Superpowers Licence MIT ↗ Revision 5bf4e7801107 Read what was—and wasn’t—checked ↓ “Use when implementing any feature or bugfix, before writing implementation code” Jesse Vincent / Superpowers · upstream description ↗ Our analysis follows below. 01 / THE REASONING ## Why this made the selection. - Requires verifying why a test fails before changing implementation, then running the project suite after the fix. - Its test-design reference rejects mirrored expectations, source-text assertions and tests that only prove mocks were installed. ### A good fit for - Implementing a bounded feature with a clear behavior contract - Adding a regression test before repairing a bug ### Weigh up before choosing - The workflow is deliberately prescriptive: it tells an agent to discard implementation written before tests and seek permission for exceptions. - Test-first work still needs an independent specification; a green suite cannot establish missing requirements or production readiness. 02 / THE REVIEW RECORD ## What we actually inspected. Source review has boundaries. A clear record is more useful than a “safe” badge. ### Material inspected - skills/test-driven-development/SKILL.md - skills/test-driven-development/writing-good-tests.md - LICENSE ### Our findings - The definition separates expected assertion failures from errors caused by broken test setup. - The reference requires hand-derived expectations and naming the production mutation each test should catch. - Mock guidance preserves real side effects and reserves test-only cleanup for test utilities. ### Not established by this review - No consuming agent was evaluated for adherence to the process. - No generated tests or production changes were executed. The review applies to the material and revision named here. A newer upstream release can change its behavior. 03 / PUT IT TO WORK ## Add a skill to your workflow. Upstream setup instructions ↗ DOCUMENTED COMMAND npx skills add https://github.com/obra/superpowers/tree/5bf4e78011075bcfc0dc295f0724994cd123ee71/skills/test-driven-development Copy command ↗ Copying does not execute this command. It may retrieve a newer version than the reviewed source. - Install the complete skill directory with its references and helpers; a copied SKILL.md alone may be incomplete. - Choose the intended agent and project scope in the installer, then review its permissions before using the skill. ### Before you start - Node.js/npm for this installer - An agent that supports the Agent Skills format - A working project test command and permission to edit relevant code/tests ### Compatibility Superpowers-supported coding agents · Project-specific test runners ### Repository edits and test commands - Read and edit implementation and tests - Run project test commands, including the broader suite - Potentially discard premature implementation under the skill instructions ### Cost model The skill is MIT-licensed; agent calls, local test resources and external test services remain separate. 04 / FOLLOW THE EVIDENCE ## The source trail. Our notes are separate from the original resource. Check upstream before adopting a new version. - Skill definition at reviewed revision ↗ Checked 2026-09-21 https://github.com/obra/superpowers/blob/5bf4e78011075bcfc0dc295f0724994cd123ee71/skills/test-driven-development/SKILL.md Supports: summary, upstreamDescription, whySelected, bestFor, limitations, review, compatibility, access - Reviewed reference or helper: writing-good-tests.md ↗ Checked 2026-09-21 https://github.com/obra/superpowers/blob/5bf4e78011075bcfc0dc295f0724994cd123ee71/skills/test-driven-development/writing-good-tests.md Supports: review, limitations, access - Upstream license or licensing declaration ↗ Checked 2026-09-21 https://github.com/obra/superpowers/blob/5bf4e78011075bcfc0dc295f0724994cd123ee71/LICENSE Supports: license - Publisher installation and project documentation ↗ Checked 2026-09-21 https://github.com/obra/superpowers/blob/5bf4e78011075bcfc0dc295f0724994cd123ee71/README.md Supports: install, compatibility, access - Skills installer source formats and selective installation ↗ Checked 2026-09-21 https://github.com/vercel-labs/skills/blob/7407f3893ad4dceab546ac002c3ef806e4000c73/README.md Supports: install - Installer implementation: full commit SHA fallback ↗ Checked 2026-09-21 https://github.com/vercel-labs/skills/blob/7407f3893ad4dceab546ac002c3ef806e4000c73/src/git.ts Supports: install KEEP COMPARING ## Other approaches to consider. Related by category or shared topics. These are alternatives to inspect, not a measured quality order. [### Diagnosing Bugs ↗ A debugging procedure that establishes a reproducible symptom, tests competing explanations and preserves a regression check.](/skills/mattpocock-diagnosing-bugs/)[### Bug Receipt ↗ Creates an evidence-bearing defect or incident handoff that distinguishes verified, partial and blocked outcomes.](/skills/github-bug-receipt/)[### Sentry Find Bugs ↗ Reviews a branch diff against surrounding code and existing tests, reporting only substantiated issues and explicit coverage limits.](/skills/getsentry-find-bugs/) [AI Tools ↗](/tools/)[Skills ↗](/skills/)[Agents ↗](/agents/)[MCP Servers ↗](/mcp-servers/)