claude4spec

claude4spec runs from a single command — no persistent install. Run it in the directory where you want your spec to live: this can be your project's repo, but it doesn't have to be. The first run creates a .claude4spec/ directory there and opens the editor in your browser at http://localhost:4500.

$npx @inharness-ai/claude4spec

Onboarding

The first run walks you through a short setup: you give the project a name and pick a writing style, then the tool gets out of your way.

The writing style is the house style for your spec. It tells the agent how to draft and organize your entities — how the spec is structured and sliced, how things are named, and the conventions it follows when it writes on your behalf — so the result reads the way you plan rather than however the model defaults. Pick the one that matches how you like to work, or choose None and set it later. You can change it anytime.

What gets created

The first run scaffolds a .claude4spec/ directory in your project:

.claude4spec/
├─ db.sqlite        # entities, sections, tags, version history
├─ config.json      # project name, port, pages dir, writing style
├─ mcp.json         # MCP server registration for your agent
├─ briefs/          # generated implementation briefs (per release)
├─ patches/         # drift feedback written back from implementation
└─ skills/          # Claude Code skills: c4s-spec-reader, c4s-brief-implementer

Your spec pages live in a pages/ directory at the repo root (not inside .claude4spec/), so they sit next to your code and diff in git.

The editor opens

The editor runs at http://localhost:4500 with three panes: a sidebar with your pages and entity search, the editor itself, and an agent chat. The agent chat requires Claude Code to be installed and authenticated.

Common flags

--clone <slug>Start from a published spec instead of a blank project.

--port <n>Run the editor on a port other than 4500.

--name <name>Set the project name non-interactively.

--pages <dir>Point at a pages directory other than ./pages.

--no-openDon't open a browser tab on launch.

Claude Code

The agent chat is powered by Claude Code. If you don't have it yet, download it from claude.com/product/claude-code. Authenticate once with claude login — you can use it on your Claude subscription, or generate an ANTHROPIC_API_KEY and use that instead.