spec-first

Write the requirements before you write the code. Spec First gives you a workflow with three steps. First, define what to build. Then implement it from the spec. Last, generate the documentation. All steps run in your terminal.

Give an agent a vague prompt, and the agent decides the requirements for you. You find out what it decided when you read the diff. A wrong decision then costs you the whole change.

Spec First puts the requirements in a file first. You read that file and correct it. The agent builds from the file you approved.

Use Spec First if you want your coding agent to build from clear requirements.

On Claude Code, add the marketplace. Then install the plugin:

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

On another host, install the skills with ./scripts/install.sh. The host table below gives the command for each host.

New to Spec First? Getting Started walks through your first spec.

Each command gives the same steps and the same checks to every host.

• You approve the requirements first. /sf:spec writes .sf/spec.md. You read that file and correct it before the agent writes code.
• The implement step copies a pattern from your repo. It finds the closest existing example and follows it. It does not invent a structure.
• The checks are gates. A script fails when the spec misses a section, or when an acceptance criterion stays unchecked. On Claude Code a hook blocks the turn. On another host the skill stops the agent from reporting the work as done.
• Claude Code does the independent work in parallel. /sf:spec and /sf:document run as workflow scripts. Every other host does the same steps in order.

The spec stays on your machine. Team Workflow shows how a team shares it through the ticket.

The table shows the typical range for each phase. The example is a small CLI tool with approximately 500 lines.

Your token counts change with the size of the codebase, the complexity of the feature, and the number of iterations. For current prices, see Claude pricing.

Supported hosts gives the directory each host reads, the documentation it came from, and the version it was read at. A host not listed there: check its skill documentation for the directory it reads, then pass that with --dir.