Speclock

Rules files tell AI what not to change.SpecLock enforces them.

Stop Claude Code, Cursor, Codex, Windsurf, and other AI coding tools from crossing project constraints you already wrote in CLAUDE.md, AGENTS.md, and .cursorrules.

Install · See a block · Claude Code plugin · Website · Saves Wall

Why another rules tool? Rules files are context. They can be forgotten, diluted, or overridden during a long coding session. SpecLock turns those rules into checks that run before edits, shell commands, and commits.

See the difference

CLAUDE.md:  Never modify the authentication system.

You:        Add social login to the login page.

Without SpecLock
Claude:     I'll update the auth flow and add an OAuth provider...

With SpecLock (strict mode)
SpecLock:   BLOCKED — conflicts with "Never modify the authentication system"
            Match: login → auth → authentication
            The action was denied before the files changed.

SpecLock uses semantic conflict detection rather than simple keyword matching. It catches indirect actions such as “clean up old patient data,” “streamline checkout,” or “temporarily disable MFA” when they violate an active constraint.

60-second setup

Run this from the project you want to protect:

npx speclock@latest protect          # reads existing AI rule files; advisory by default
npx speclock@latest doctor           # confirms rules, hooks, and integration

When the advisory output looks right, enable blocking:

npx speclock@latest protect --strict

No account is required. SpecLock runs locally by default, and advisory mode never blocks a change.

Install as a Claude Code plugin

Inside Claude Code, run:

/plugin marketplace add sgroy10/speclock
/plugin install speclock@speclock-marketplace

Then protect the current project once:

npx speclock@latest protect          # warnings only
npx speclock@latest protect --strict # block confirmed conflicts

The plugin automatically starts SpecLock's MCP server and checks Claude Code Write, Edit, and Bash actions before execution. It includes all 51 MCP tools and works alongside your existing CLAUDE.md.

Install on other coding agents

SpecLock is packaged for multiple agent ecosystems, but the enforcement level depends on what each host exposes:

Platform	Install/discovery path	Protection level
Claude Code	Native marketplace plugin above	Native pre-action checks for Write, Edit, and Bash
Gemini CLI	Install this repository as a Gemini extension	MCP-assisted checks plus project context
Cursor	Agent Plugin / Cursor marketplace package	MCP-assisted checks plus rules
Codex	Repository Codex plugin in plugins/speclock	MCP-assisted checks plus $speclock-guardrails skill
GitHub Copilot CLI	Add this repository as a plugin marketplace	MCP-assisted checks plus bundled plugin context
Cline	MCP server; curated marketplace submission in progress	MCP-assisted checks
Windsurf	speclock mcp install windsurf	MCP-assisted checks plus rules
Any Git client or CI	speclock protect	Commit/CI enforcement independent of the coding agent