rev-eng-cursor-regex-mcp

rev-eng-cursor-regex-mcp is a portable TypeScript Model Context Protocol server for fast literal and regex search over local workspaces. It uses a sparse n-gram index for candidate pruning, then performs deterministic verification against the real file contents.

Features

• index.ensure, index.status, and index.clear for local index lifecycle management

• Automatic .gitignore bootstrap for the local .rev-eng-cursor-regex-mcp/ cache when that cache lives inside the workspace

• search.literal for exact-string search

• search.regex for ECMAScript regex search with sparse n-gram planning

• query.explain for anchor extraction and fallback analysis

• document.inspect_terms for trigram, masked-trigram, and sparse-term diagnostics

• Static resources for algorithm notes, storage layout, and agent workflow guidance

• Reusable prompts for investigation flow and regex refinement

• stdio and Streamable HTTP entrypoints

Related MCP server: File Search MCP

Requirements

• Node.js 20 or newer

Quick Start From Source

npm install
npm run build
npm run start:stdio

This starts the MCP server over stdio from a fresh clone with no global install required.

Run Modes

Run over stdio from a local clone:

npm run start:stdio

Run over Streamable HTTP from a local clone:

npm run start:http

Run the built CLI directly:

node dist/cli.js stdio
node dist/cli.js http --host 127.0.0.1 --port 3333

Run without cloning after the package is published:

npx rev-eng-cursor-regex-mcp stdio
npx rev-eng-cursor-regex-mcp http --host 127.0.0.1 --port 3333

Environment

• REV_ENG_CURSOR_REGEX_MCP_WORKSPACE_ROOT: default workspace root

• REV_ENG_CURSOR_REGEX_MCP_INDEX_DIR: parent directory where .rev-eng-cursor-regex-mcp/ is created

• REV_ENG_CURSOR_REGEX_MCP_BOOTSTRAP_GITIGNORE: when set to false, 0, off, or no, skip automatic .gitignore bootstrapping

• REV_ENG_CURSOR_REGEX_MCP_HTTP_HOST: default HTTP bind host

• REV_ENG_CURSOR_REGEX_MCP_HTTP_PORT: default HTTP bind port

Verify A Fresh Clone

npm install
npm run typecheck
npm test
npm run build

Claude Desktop Example

{
  "mcpServers": {
    "rev-eng-cursor-regex-mcp": {
      "command": "node",
      "args": [
        "/absolute/path/to/rev-eng-cursor-regex-mcp/dist/cli.js",
        "stdio"
      ]
    }
  }
}

Notes

• Git workspaces use a commit-keyed base index plus a mutable overlay for working-tree changes.

• index.ensure adds the cache directory to .gitignore automatically when the cache root lives inside the workspace. Pass bootstrapGitignore: false or set REV_ENG_CURSOR_REGEX_MCP_BOOTSTRAP_GITIGNORE=false to opt out.

• Non-git workspaces fall back to snapshot mode with .gitignore-style filtering.

• Ignore-case regex searches fall back to a deterministic full scan because the sparse index is case-sensitive.