Narsil MCP Server

A Rust-powered MCP (Model Context Protocol) server providing AI assistants with deep code understanding through 90 specialized tools.

Remote serverstreamable-httpPython

What is the Narsil MCP MCP server?

A Rust-powered MCP (Model Context Protocol) server providing AI assistants with deep code understanding through 90 specialized tools. The narsil mcp mcp server wraps that behind the Model Context Protocol, so an assistant can use it through 12 defined tools rather than through you.

Its toolset

Everything the assistant can do here goes through one of these:

  • EMBEDDING_API_KEY — Generic API key for any provider
  • VOYAGE_API_KEY — Voyage AI specific API key
  • OPENAI_API_KEY — OpenAI specific API key
  • EMBEDDING_SERVER_ENDPOINT — Custom embedding API endpoint URL (optional, allows using self-hosted models)
  • Feature — Description
  • graph — + RDF knowledge graph, SPARQL, CCG tools
  • frontend — + Embedded visualization web UI
  • neural — + TF-IDF vector search, API embeddings
  • neural-onnx — + Local ONNX model inference
  • wasm — Browser build (no file system, git)
  • Configuration — The Configuration tool exposed by this server
  • Presets — The Presets tool exposed by this server

Adding it to your client

Being a remote server, there is no local install. You register the endpoint with your client, authorise it once, and the tools appear.

Configuration

You will need 8 environment variables: NARSIL_REPOS, NARSIL_PROFILE, NARSIL_PRESET, NARSIL_ENABLED_CATEGORIES, NARSIL_DISABLED_TOOLS, VOYAGE_API_KEY, EMBEDDING_API_KEY, OPENAI_API_KEY. The server will not start without them, which is usually why the tools fail to appear on a first run. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

When to reach for it

This sits in the AI and media services group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Narsil MCP's toolset — EMBEDDING_API_KEY, VOYAGE_API_KEY, OPENAI_API_KEY and 9 more — is a fair guide to whether it matches your workflow. It is maintained by postrv; worth a glance at recent repository activity before you build anything load-bearing on it.

We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.

Caveats

  • Your data travels to the provider's service, so the usual questions apply about what you send and what they retain.
  • With 12 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch Narsil MCP.
  • Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the narsil mcp mcp server does with a few real requests.

Available tools

ToolWhat it does
EMBEDDING_API_KEYGeneric API key for any provider
VOYAGE_API_KEYVoyage AI specific API key
OPENAI_API_KEYOpenAI specific API key
EMBEDDING_SERVER_ENDPOINTCustom embedding API endpoint URL (optional, allows using self-hosted models)
FeatureDescription
graph+ RDF knowledge graph, SPARQL, CCG tools
frontend+ Embedded visualization web UI
neural+ TF-IDF vector search, API embeddings
neural-onnx+ Local ONNX model inference
wasmBrowser build (no file system, git)
ConfigurationThe Configuration tool exposed by this server.
PresetsThe Presets tool exposed by this server.

How to install the Narsil MCP MCP server

{
  "mcpServers": {
    "narsil": {
      "command": "npx",
      "args": ["-y", "narsil-mcp"],
      "env": {
        "NARSIL_REPOS": "your-value",
        "NARSIL_PROFILE": "your-value",
        "NARSIL_PRESET": "your-value",
        "NARSIL_ENABLED_CATEGORIES": "your-value",
        "NARSIL_DISABLED_TOOLS": "your-value",
        "VOYAGE_API_KEY": "your-value",
        "EMBEDDING_API_KEY": "your-value",
        "OPENAI_API_KEY": "your-value"
      }
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

VariableDescriptionRequired
NARSIL_REPOSConfiguration value read at startup.Optional
NARSIL_PROFILEConfiguration value read at startup.Optional
NARSIL_PRESETConfiguration value read at startup.Optional
NARSIL_ENABLED_CATEGORIESConfiguration value read at startup.Optional
NARSIL_DISABLED_TOOLSConfiguration value read at startup.Optional
VOYAGE_API_KEYCredential the server authenticates with.Yes
EMBEDDING_API_KEYCredential the server authenticates with.Yes
OPENAI_API_KEYCredential the server authenticates with.Yes

Example prompts to try

  • Use Narsil MCP to EMBEDDING API KEY.
  • Use Narsil MCP to VOYAGE API KEY.
  • Use Narsil MCP to OPENAI API KEY.

Frequently asked questions

It connects Narsil MCP to MCP-compatible AI assistants such as Claude and Cursor, exposing 12 tools (EMBEDDING_API_KEY, VOYAGE_API_KEY, OPENAI_API_KEY, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Narsil MCP directly.