unicode-security-mcp

A local-first MCP server for catching Unicode tricks before they become confusing bug reports or security incidents.

Tools

• analyze_text: detect confusable characters, invisible controls, mixed scripts, and a heuristic risk level.
• compare_identifiers: compare two names through a small confusable skeleton.
• get_skeleton: normalize one identifier for local comparison.

The server never sends input to a network service. It is a review aid, not a complete Unicode Security Mechanisms implementation. The bundled mappings are intentionally conservative and should not replace platform IDNA, normalization, font, or language-specific security review.

Run

npm install
npm run build
node dist/index.js

Quick start

npm install
npm run build
node dist/index.js

The server uses stdio, so it can be connected to Claude Desktop, Cursor, VS Code, MCP Inspector, or another compatible MCP client.

Tools at a glance

• analyze_text: Analyze text locally for Unicode confusables, mixed scripts, invisible controls, and a heuristic risk score. Input is never sent anywhere.
• compare_identifiers: Compare two identifiers using a Unicode-aware confusable skeleton. This is a warning aid, not a complete security proof.
• get_skeleton: Return a local normalized confusable skeleton for one identifier.

Limits and privacy

This project is intentionally narrow. It should be treated as a practical helper, not a complete certification or security audit. Check the implementation and the returned data before using it with sensitive material. No credentials are required unless the project explicitly says otherwise.

Try it

After building, connect the server through your MCP client. The repository root also contains smoke-test.mjs for projects covered by the shared harness. A typical tool call starts with analyze_text.

Licence — no paywall

Every tool in this package is free: no licence key, no premium tier, no hosted licence gateway. The paywall machinery this repo once carried (per-tool licence checks and paid hosted endpoints) was removed repo-wide on 2026-10-17. Nothing that this package installs or calls asks you to pay.