zenoh-plugin-mcp

A zenoh plugin that exposes an MCP (Model Context Protocol) server, allowing LLM agents to interact with a live zenoh network.

Features

• 29 MCP tools for pub/sub, queries, subscriptions, queryables, network discovery, liveliness, and key expression utilities
• 3 MCP prompts for guided network discovery, topic monitoring, and request/response workflows
• MCP resources exposing session info, subscription buffers, and queryable queues
• SSE transport — multiple MCP clients can connect concurrently with isolated state
• Per-client lifecycle — subscriptions, queryables, and liveliness tokens auto-cleanup on disconnect
• Access control — configurable allow/deny regex filters on key expressions
• Scope prefix — optional key expression prefix applied to all operations
• Dual mode — runs as a zenohd plugin or as a standalone bridge binary

Screenshots

Claude Code connected to zenoh network, using the discover_network prompt

Querying a zenoh queryable through MCP tools

Subscribing to zenoh topics and receiving real-time messages

Viewing network topology with zenoh_get_topology

Quick Start

Bridge mode (standalone)

# Build
cargo build --release

# Start with a zenoh router
zenoh-bridge-mcp -e tcp/127.0.0.1:7447 --mcp-listen 0.0.0.0:8808

Plugin mode (inside zenohd)

Add to your zenoh config:

{
  plugins: {
    mcp: {
      listen: "0.0.0.0:8808"
    }
  }
}

Then start zenohd with the plugin library in its search path.

Connect an MCP client

The MCP server listens on the configured address (default 0.0.0.0:8808) using the Streamable HTTP transport (SSE). Configure your MCP client to connect to http://<host>:8808/mcp.

Using with AI Coding Tools

Once the bridge or plugin is running, configure your AI tool to connect to it as a remote MCP server.

Claude Code (CLI)

claude mcp add zenoh --transport http http://localhost:8808/mcp

This registers the zenoh MCP server for all future Claude Code sessions. To verify:

claude mcp list

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "zenoh": {
      "url": "http://localhost:8808/mcp"
    }
  }
}

Restart Claude Desktop. The zenoh tools will appear in the tool picker (hammer icon).

Cursor

Open Cursor Settings > MCP, click "Add new MCP server", and configure:

• Name: zenoh
• Type: http
• URL: http://localhost:8808/mcp

Or edit .cursor/mcp.json in your project root (or ~/.cursor/mcp.json globally):

{
  "mcpServers": {
    "zenoh": {
      "type": "http",
      "url": "http://localhost:8808/mcp"
    }
  }
}

VS Code (GitHub Copilot)

Add to your VS Code settings.json (user or workspace):

{
  "mcp": {
    "servers": {
      "zenoh": {
        "type": "http",
        "url": "http://localhost:8808/mcp"
      }
    }
  }
}

Or add a .vscode/mcp.json file to your project:

{
  "servers": {
    "zenoh": {
      "type": "http",
      "url": "http://localhost:8808/mcp"
    }
  }
}

Windsurf

Edit ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "zenoh": {
      "serverUrl": "http://localhost:8808/mcp"
    }
  }
}

Any MCP-compatible client

The server endpoint is:

POST http://<host>:8808/mcp
Headers:
  Content-Type: application/json
  Accept: application/json, text/event-stream

The server follows the MCP Streamable HTTP transport spec:

• POST /mcp — send JSON-RPC requests, receive SSE responses
• GET /mcp — open SSE stream for server-initiated notifications (requires Mcp-Session-Id)
• DELETE /mcp — close a session

Remote access

If the bridge runs on a different machine, replace localhost with the host's IP or hostname. There is no built-in authentication, so restrict access at the network level (firewall, VPN, etc.).

Verifying the connection

Once connected, ask your AI assistant:

"Use the zenoh_info tool to show me the session information"

If the connection works, you'll see the zenoh session ID and any connected routers/peers. Then try:

"Discover the zenoh network" (this triggers the discover_network prompt)

MCP Tools

Core Pub/Sub/Query

Tool	Description
zenoh_put	Publish a value to a key expression
zenoh_delete	Delete a key expression (tombstone)
zenoh_get	Send a query and collect replies
zenoh_subscribe	Subscribe to a key expression (buffered)
zenoh_unsubscribe	Remove a subscription
zenoh_poll_subscription	Drain buffered samples

Queryables

Tool	Description
zenoh_declare_queryable	Register a queryable (queries buffered)
zenoh_poll_queries	Drain pending queries
zenoh_reply	Reply to a query
zenoh_reply_err	Reply with an error
zenoh_undeclare_queryable	Remove a queryable

Discovery & Network Introspection

Tool	Description
zenoh_scout	Discover routers/peers via multicast
zenoh_info	Get session ZID, connected routers/peers
zenoh_list_publishers	List declared publishers
zenoh_list_subscribers	List declared subscribers
zenoh_list_queryables	List declared queryables
zenoh_list_transports	List connected transports with link details
zenoh_get_topology	Get linkstate graph (DOT format)
zenoh_get_node_info	Get node version, locators, sessions, plugins
zenoh_get_metrics	Get OpenMetrics statistics
zenoh_get_plugins	List loaded plugins
zenoh_admin_query	Raw admin space query

Liveliness

Tool	Description
zenoh_liveliness_get	Query alive tokens
zenoh_liveliness_declare	Declare a token
zenoh_liveliness_subscribe	Subscribe to changes
zenoh_liveliness_undeclare	Undeclare a token

Key Expression Utilities

Tool	Description
zenoh_key_expr_check	Validate and canonize
zenoh_key_expr_intersects	Check intersection
zenoh_key_expr_includes	Check inclusion

Configuration

{
  plugins: {
    mcp: {
      // HTTP listen address for SSE transport
      listen: "0.0.0.0:8808",

      // Optional key expression prefix for all operations
      // scope: "factory-1",

      // Buffer sizes
      subscription_buffer_size: 1000,
      queryable_buffer_size: 100,

      // Defaults
      default_get_timeout_ms: 5000,
      default_encoding: "text/plain",

      // Access control (regex)
      // allow: "^demo/.*",
      // deny: "^internal/.*",

      // Admin space access
      admin_space_access: true,
    }
  }
}

Building

cargo build --release

Artifacts:

• target/release/libzenoh_plugin_mcp.dylib (or .so) — plugin for zenohd
• target/release/zenoh-bridge-mcp — standalone bridge

Testing

cargo test -- --test-threads=1

Architecture

zenohd / bridge
  └── zenoh-plugin-mcp
        ├── MCP Server (SSE/HTTP, multi-client)
        │     ├── Per-client McpSessionState
        │     │     ├── Subscriptions (ring buffers)
        │     │     ├── Queryables (pending query buffers)
        │     │     └── Liveliness tokens
        │     ├── 29 Tools
        │     ├── 3 Prompts
        │     └── Resources
        └── Zenoh Session (from runtime)

License

MIT