GitHub Spec Kit with Claude Code, for the whole team
Spec Kit gives your developer a spec-first workflow in the repository. Feature1, the product operating system, gives the rest of the team a place to write, agree and track the spec, and Claude Code reads it over MCP.
What is GitHub Spec Kit?
GitHub Spec Kit is an open-source toolkit from GitHub for spec-driven development. It keeps a constitution, a specification, a plan and tasks as files in the repository, and drives coding agents such as Claude Code, Codex and Cursor through them with slash commands.
Constitution
The project’s principles and rules.
Specify
What to build and why.
Plan
How it will be built.
Tasks and implement
The agent works through the tasks.
Where Spec Kit stops for a team
Spec Kit is built around the developer and the repository. When the rest of the team needs to work on the spec, it gets harder:
- The PM needs a branch and a pull request to change one sentence.
- Two people edit the same spec and hit a merge conflict on plain English.
- Task sync to Jira or Linear goes one way, and the reasons stay in a markdown file.
- The file cannot hold the customer signals behind the spec, its approved revisions, progress, or whether the feature is used after release.
Feature1 keeps the spec where the whole team can work on it, with everything around it attached. Your developer keeps Spec Kit.
New to Spec Kit? Set it up with your team
Book a proof of concept (POC). We set Spec Kit and Feature1 up with your PM and one developer and stay with you, hands on, until two real features are delivered.
- Week 1. NDA, read-only GitHub access, then the product strategy and roadmap with your PM in Feature1. The first two features are specified with acceptance criteria.
- Week 2. Your developer runs Spec Kit with Claude Code, which reads the criteria over MCP, and builds both features. We review against the criteria together and ship.
Proof of concept (POC)
$500 paid only when the two features ship
- One to two weeks, your PM and one developer
- Your developer writes the code; we guide the process
- You keep the strategy, roadmap and specs
Already running Spec Kit? Keep it and bring your PM in
Your developer keeps the Spec Kit workflow. Feature1 becomes where the PM and the rest of the team work on the spec.
- Write and comment on specs without touching Git, and approve each revision.
- Link every spec to the initiative and customer signals behind it.
- Feature1 exports the spec, plan and tasks files for your developer to commit.
- See progress story by story, then adoption and errors after release.
7-day free trial
Free no credit card
Sign up, invite your PM and move your next spec into Feature1. Connect Claude Code when you are ready.
Start the free trialTeams already working this way
- SatoriXR. Delivery got faster and deciding became the constraint. They hired a second product manager, not a third developer.
- Quantem. A junior developer built an MCP layer in one day from written acceptance criteria. The context took four to five days; the build took one.
- Jarshare. A Replit store with one unintegrated server file became a real product once its next features were specified against what it already did.
Spec Kit: questions people ask
What is GitHub Spec Kit?
An open-source toolkit from GitHub for spec-driven development. It keeps the constitution, specification, plan and tasks as files in the repository and drives coding agents through them with slash commands.
Is Feature1 a Spec Kit alternative?
No. Spec Kit organises the spec, plan and tasks inside the repository for the developer. Feature1 is the product layer above it, where the strategy, roadmap and acceptance criteria are decided and agreed. Teams use both.
How does Claude Code get the acceptance criteria from Feature1?
Over MCP. Feature1 exposes features, stories and acceptance criteria as MCP tools, and Claude Code reads them while it specifies and plans.
Does Feature1 write to our repository?
No. Feature1 reads the repository read-only. It exports Spec Kit files, and your developer or their agent commits them.
Which agents does this work with?
Claude Code, Codex, Cursor and any MCP-compatible agent, which covers the agents Spec Kit supports.
What is in the POC?
One to two weeks with your PM and one developer. We set the workflow up with your team and stay with you until two features are delivered from acceptance criteria held in Feature1. An NDA is signed before anything is read, GitHub access is read-only, and you pay the $500 only when the two features ship.
Is there a free trial?
Yes. Feature1 has a 7-day free trial with no credit card. Invite your team, write your first specs together and connect your coding agent.