spec-writer — Claude Code skill: spec from a description
Transforms a vague feature request into a structured specification, technical plan, and task breakdown. Every assumption is marked inline so you can correct it before handing off to an agent.
npx skills add dannwaneri/spec-writer --skill spec-writer -a claude-codeWhat spec-writer does
spec-writer takes a rough request—"add password reset"—and produces three sections: a spec with user stories and Given/When/Then acceptance criteria, a technical plan covering architecture and data model changes, and a list of ordered, independently testable tasks. Each assumption gets flagged with [ASSUMPTION: ...] in the output itself, so decisions that would be invisible in a chat become explicit and editable.
Output is compatible with GitHub Spec Kit and OpenSpec frameworks, so you can save it to .specify/ or openspec/changes/ and continue from there. Specs stay technology-neutral—no framework names, only functional requirements and the business logic that matters.
What it helps with
- turn a brief feature description into a full specification
- break a vague request into concrete tasks for a coding agent
- surface assumptions before development starts
- generate a technical plan with data models and API contracts
- export a spec compatible with Spec Kit or OpenSpec
Example prompts for the agent
- /spec-writer Add a way for users to reset their password
- /spec-writer Build an admin dashboard that shows daily signups by region
- /spec-writer Let users export their project data as CSV
How to install spec-writer
1Skills CLI (Vercel)
npx skills add dannwaneri/spec-writer --skill spec-writer -a claude-code2Manually: put the files in place
~/.claude/skills/spec-writer/SKILL.mdCopy the whole skill folder; for one project use .claude/skills/spec-writer/
1Skills CLI (Vercel)
npx skills add dannwaneri/spec-writer --skill spec-writer -a codex2Manually: put the files in place
.agents/skills/spec-writer/SKILL.mdFor all projects use ~/.agents/skills/
1Skills CLI (Vercel)
npx skills add dannwaneri/spec-writer --skill spec-writer -a cursor2Manually: put the files in place
.cursor/skills/spec-writer/SKILL.mdCursor also reads .agents/skills/ and .claude/skills/
1GitHub CLI
gh skill install dannwaneri/spec-writer spec-writer2Manually: put the files in place
.github/skills/spec-writer/SKILL.md1Skills CLI (Vercel)
npx skills add dannwaneri/spec-writer --skill spec-writer -a gemini-cli2Platform CLI
gemini skills install https://github.com/dannwaneri/spec-writerManually: put the files in place
.devin/skills/spec-writer/SKILL.mdThe legacy .windsurf/skills/ path still works
Skills CLI (Vercel)
npx skills add dannwaneri/spec-writer --skill spec-writer -a opencodeClaude.ai
Zip the folder and upload it in Settings → Capabilities → Skills
Step by step, with commands for each platform: How to install skills in Claude Code: five ways
Questions about spec-writer
How do I install spec-writer in Claude Code?
Run npx skills add dannwaneri/spec-writer --skill spec-writer -a claude-code, then check the config at ~/.claude/skills/spec-writer/SKILL.md.
What does spec-writer output?
Three parts: a specification with user cases and acceptance criteria in Given/When/Then format, a technical plan that covers architecture and API contracts, and a prioritized list of tasks. Every unstated decision is marked [ASSUMPTION: ...] for you to review.
Can I use spec-writer output with Spec Kit or OpenSpec?
Yes. The format is compatible with both GitHub Spec Kit and OpenSpec. Save the output to .specify/ or openspec/changes/ and continue using the framework from there.
