sf

spec-first

Build faster by writing requirements before code. This Claude Code plugin enforces a three-step workflow: define what to build, implement it from the spec, and generate documentation — all from your terminal.

Who is this for

Engineers and teams who want Claude Code to stop guessing and start building from clear requirements.

Quick Start

Add the marketplace and install the plugin from your terminal:

claude plugin marketplace add bitcraft-apps/spec-first
claude plugin install sf@spec-first

Or from within Claude Code:

/plugin marketplace add bitcraft-apps/spec-first
/plugin install sf@spec-first

Write your first spec:

/sf:spec Add a rate limiter to the API gateway

Researching requirements...

  Batch 1 (parallel): define-scope, create-criteria, identify-risks
  Batch 2: synthesize-spec

Spec written to .claude/.sf/spec.md

Implement it:

/sf:implement

Step 1: Learning patterns from codebase...
  Found: src/middleware/auth.ts (similar middleware pattern)

Step 2: Implementing...
  Created: src/middleware/rate-limiter.ts
  Updated: src/middleware/index.ts
  Created: src/middleware/rate-limiter.test.ts

Implementation summary written to .claude/.sf/implementation-summary.md

Document it:

/sf:document

Batch 1 (parallel): analyze-artifacts, analyze-implementation, analyze-existing-docs
Batch 2 (parallel): create-technical-docs, create-user-docs
Batch 3: integrate-docs

Updated: docs/middleware.md (added rate limiter section)

How it works

Each command orchestrates specialized agents that run in parallel where possible. The spec is the contract between define and implement — no spec, no code.

Token Usage

Typical ranges per phase (example: small CLI tool, ~500 lines):

Phase	Input tokens	Output tokens
spec	10k–30k	2k–6k
implement	30k–120k	5k–30k
document	20k–60k	3k–10k

Actual usage varies with codebase size, feature complexity, and iteration count. For current pricing, see Claude pricing.

Command Reference

Command	Purpose
/sf:spec [REQUIREMENTS]	Define what to build and why
/sf:implement [--isolate] [SPEC_OR_PATH]	Build the minimal working solution
/sf:document [PATHS]	Generate docs proportional to the change

Requirements

• Claude Code CLI