Summary

Enforcement level depends on the client, and the README says which is which.

Claude Code gets native pre-action checks on Write, Edit and Bash. Everywhere else — Cursor, Windsurf, Cline, Codex, Gemini CLI, Copilot CLI — the agent can call SpecLock before acting but nothing guarantees it will, which the project labels MCP-assisted rather than pretending otherwise. If a constraint genuinely must hold, the answer given is `speclock protect --strict` plus CI, where enforcement does not depend on the coding agent at all. Start advisory: it never blocks a change while you find out what it would have caught.

What it is

A constraint enforcement layer for coding agents. It reads the rule files you already keep — CLAUDE.md, AGENTS.md, .cursorrules — turns them into locks, and checks proposed actions against them, in advisory mode by default and blocking when you switch it on.

What you get

51 MCP tools in total, spanning context, constraints, enforcement, sessions and audit
speclock_check_conflict runs a semantic conflict check against every active lock, and speclock_get_context returns the full context pack
speclock_add_lock adds a constraint and auto-guards the matching files; speclock_remove_lock soft-deletes one and speclock_suggest_locks proposes new ones
speclock_set_enforcement switches between advisory and hard mode; speclock_override_lock records an override with a reason and speclock_override_history reads that trail back
speclock_semantic_audit analyses a git diff against the locks, speclock_detect_drift scans for violations, and speclock_audit checks staged files before a commit
speclock_session_briefing and speclock_session_summary bracket a working session; speclock_log_change, speclock_get_changes and speclock_get_events track what happened inside it
speclock_verify_audit checks the integrity of the HMAC audit chain, and speclock_report gives violation statistics and the most-tested locks
Matching is semantic rather than keyword: "clean up old patient data" reads as deletion, "temporarily disable MFA" as disabling MFA, and "enable audit logging" does not trip a lock that forbids disabling it

Requirements

The npm package speclock, version 5.8.0, started as `speclock serve --project .` over stdio, or installed as a Claude Code plugin from the repository's marketplace. Run `npx speclock@latest protect` once in the project to extract constraints — that starts advisory. `protect --strict` turns on blocking, and `speclock doctor` verifies rules, hooks and integration. No account; it runs locally by default.

Setup effort

One command — npx speclock@latest protect