Security

Security, by design.

Notemcpseal is designed to detect and block MCP tool-definition drift. It does not claim to eliminate every class of security risk.
01

Local-first

Track A — the CLI — runs entirely on your machine. There is no server, no database, and no signup required for local protection.

02

Fail-closed

If integrity cannot be established — a missing lockfile entry, a hash mismatch, an unreadable definition — the tool is blocked. mcpseal never treats an unverifiable state as safe.

03

Cryptographic fingerprinting

Each tool is fingerprinted with SHA-256 over its name, description, and inputSchema. The fingerprint is recorded in .mcp-lock.json and re-checked on every call.

04

What is verified

The name, description, and inputSchema of every tool definition passing through the proxy, checked against its approved fingerprint at call time. mcpseal does not inspect the contents of individual tool-call arguments or results.

05

What is stored locally

  • .mcp-lock.json — one fingerprint per tool
  • ~/.mcpseal/events.jsonl — a local approval and block history
  • Workspace credentials, if opted in — stored in the OS keychain, never in plaintext
06

What leaves the machine

Nothing, by default. Track A makes zero network calls. The only network activity mcpseal ever initiates is explicit: mcpseal login, mcpseal policy-pull, or an opt-in mcpseal doctor --check-updates version check.

07

Workspace opt-in

Joining a Track B workspace is an explicit action — mcpseal login, using device authorization. Nothing connects to a workspace automatically.

08

Track B security

The Control Plane adds WorkOS-backed human login, Stripe billing, and SSO/SCIM for enterprise identity and automated provisioning, on top of everything Track A already verifies.

09

Policy signing

Admins sign an approved lockfile before it's pushed. mcpseal policy-pull fetches that policy and verifies its signature before applying it locally — an unsigned or invalid policy is rejected.

10

Audit integrity

Track B audit events are hash-chained, so a tampered or deleted entry breaks the chain and is detectable independently of the Control Plane itself.

11

Responsible disclosure

We take security vulnerabilities seriously. If you discover one, report it privately rather than disclosing exploit details publicly first.

  • What to report: the affected command or component, reproduction steps, and impact
  • Include: mcpseal version, OS, and MCP client in use
  • Expect acknowledgement, then coordinated disclosure before any public write-up
  • Contact: [SECURITY CONTACT EMAIL]