Palaryn MCP Server

Agent I/O governance for every HTTP request your AI agent makes — exposed as an MCP server.

Palaryn MCP wraps the Palaryn gateway as a Model Context Protocol server, giving Claude Code, Cursor, Windsurf, and any MCP-compatible client policy-enforced access to external APIs with zero code changes.

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What It Does

Every HTTP request your AI agent makes flows through the Palaryn pipeline:

Claude Code / Cursor / MCP Client
        |
        | stdio (JSON-RPC 2.0) or HTTP (/mcp)
        v
  Palaryn MCP Server
        |
        +---> Rate Limiting     (per-actor sliding window)
        +---> Anomaly Detection (statistical outlier flagging)
        +---> Policy Engine     (YAML rules: allow / deny / require approval)
        +---> DLP Scanner       (secrets, PII, 119 detection patterns)
        +---> Prompt Injection  (3-layer cascade: regex → DeBERTa → LLM)
        +---> Call Limits       (per-user / workspace daily & monthly caps)
        +---> HTTP Execution    (retries, backoff, SSRF protection)
        +---> Output DLP Scan   (response body scanning)
        +---> Audit Logging     (immutable append-only trace)
        |
        v
   External API

Three MCP tools exposed:

Each tool accepts: url (required), headers, body, timeout_ms, purpose, labels.

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Quick Start

Option 1: Hosted (requires a Palaryn account)

claude mcp add --transport http palaryn https://app.palaryn.com/mcp

Done. All requests from Claude Code now route through Palaryn. You will be prompted to log in via OAuth on first use.

Option 2: Project-level config

Create .mcp.json in your project root (see .mcp.json.example):

{
  "mcpServers": {
    "palaryn": {
      "type": "stdio",
      "command": "npx",
      "args": ["palaryn-mcp"],
      "env": {
        "POLICY_PACK_PATH": "./policy-packs/default.yaml"
      }
    }
  }
}

Note: Ensure palaryn-mcp is installed (e.g., via npm install palaryn-mcp) so npx can resolve it.

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Configuration

Environment Variables

Custom Policy Pack

Pass a custom policy via environment variable:

claude mcp add palaryn \
  -e POLICY_PACK_PATH=./policy-packs/prod_strict.yaml \
  -- node bin/palaryn-mcp.js

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Policy Packs