← Free tools · Tool 02

Eigenspec Skill

A one-file Claude Code skill that writes implementation specs the way our founders do. Paste a problem; get back a scoped spec with assumptions, a test plan, and a risk register. We use this skill to draft the one-page scope for every paid engagement.

What "eigenspec" means. It's a spec written along the problem's natural axes — not a templated PRD. We've watched a lot of engineering work get bogged down by specs that argue about the wrong things. This skill encodes the questions we always end up asking on day one.

Install · 30 seconds

Drop a file in .claude/skills/ and you're done.

# install the skill globally for Claude Code
$ curl -L https://raw.githubusercontent.com/squatch-c-c/eigenspec-skill/main/SKILL.md \
       -o ~/.claude/skills/eigenspec/SKILL.md

# in any Claude Code session:
> /eigenspec "build a passkey auth flow for an Expo RN app, ship to TestFlight in 10 days"

 goal · risks · constraints
 3-phase plan · test plan · rollback
 one-page markdown, ready to paste in a PR

Works with Claude Code, Cursor (via .cursorrules), and Continue.dev. MIT license.

What it produces

A real one-page spec.

  • Goal & non-goals — what's in scope, sharply.
  • Assumptions & constraints — the load-bearing ones.
  • Phased plan — week 1, week 2, week 3 deliverables.
  • Test plan — the test that proves it works.
  • Risk register — ranked, with mitigations.
  • Rollback — how we back out if it doesn't.

When to use it

Three good fits.

  1. You're about to start something with >3 unknowns. (Most things.)
  2. You're scoping a vendor engagement and want a sane RFP draft.
  3. You're an engineer trying to convince the team the work is bounded.

Got a spec ready?

Hand it to us. We'll quote the build.

Use the skill to draft a spec, send it through our hire form, and we'll come back with a tier recommendation and a fixed-price bid within one business day.

Skill updates only.