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FeatherSpec Wiki

Spec-driven development that works in Claude Code and GitHub Copilot — from the same files.

The README gets you running in two minutes. This wiki holds everything else: the reference material, the reasoning behind the design, and the details you only need once you are actually using it.

Already running an older FeatherSpec? Since v1.2.0 the template is versioned and every existing project — however customized — can update safely. Copying two files in is the whole install: Updating & Versioning → Installing the updater. Cutting a template release with an AI agent: hand it Releasing.

Start here

Page	What's in it
Getting Started	Install, open in either tool, verify what actually loaded
Hands-On Walkthrough	A full SDD cycle in ~45 minutes, PO and Dev in pairs
Commands	Every /sdd-* command in detail
Updating & Versioning	Check your version, update safely, what never gets touched

Reference

Page	What's in it
Specs and Plans	Document structure, lifecycle, acceptance criteria, traceability
Memory Bank	The four files and what belongs in each
Repository Layout	Every file and folder, and why it exists
Configuration	Shared vs. local settings, auto memory, MCP, hooks
Extending FeatherSpec	Add your own commands and rules

Design and interop

Page	What's in it
Interop Matrix	Exactly what VS Code Copilot reads from .claude/, with sources
Design Decisions	Why commands and not skills, why one source of truth, the documented exceptions
Committing to One Tool	Strip out the other tool later, mechanically
Migrating from copilot-spec-driven-template	What changed from the predecessor
Releasing	How a release is cut — give this page to your AI agent

Help

Page	What's in it
Troubleshooting	Commands not showing up, rules not applying, diagnostics
FAQ	Short answers to the recurring questions

What FeatherSpec is — and is not

• Is: a repository scaffold that makes an AI coding assistant work spec-first — write a spec, have a cold second pass attack it, plan against it, read the plan, implement, prove it, and keep a small version-controlled Memory Bank in sync. The same /sdd-* commands exist in both tools because each workflow is written down once, so it reads identically in docs, videos, and talks.
• Is not: a program. There is nothing to install or run. If a feature cannot be expressed in Markdown plus native tool configuration, it does not belong here.
• Is not: a speed tool. The honest claim is variance reduction, not velocity: fewer confident wrong turns, a written record of why the code looks like it does, and a chain from every acceptance criterion to the test that decides it. If you want it to be faster on day one, it will disappoint you; if you want it to still make sense in month six, that is the trade.
• Is not: ceremony for everything. A typo does not get a spec. AGENTS.md says work spec-first for anything that changes behaviour and documents a fast path for the rest — because a workflow that demands three Markdown files for a config value teaches people to stop using it for the changes that needed it.