Status: local, read-only MCP server over stdio. Supports the current MCP 2026-07-28 stateless protocol and legacy initialization-based clients (2025-11-25, 2025-06-18, 2024-11-05).

The adapter retrieves frozen SSTIM release data from the Concept Reference API. It is not an ontology server, a write API, a hosted remote MCP endpoint, or a GitHub connector. Its four tools require no API key or additional runtime npm packages.

Distribution and authorship

Primary author and responsible project: the SSTIM W3C Community Group. The canonical source is w3c-cg/sstim.

Acknowledgement: BioSynCare, for its contributions to and support of SSTIM's wider ecosystem. BioSynCare is not the authority behind the open SSTIM vocabulary.

Community Group work is not a W3C Recommendation or a W3C-endorsed product.

Install from npm (once released)

The package is prepared for publication as @sstim/mcp@0.2.0, under the same established @sstim scope as @sstim/core. After an authorized npm publisher publishes the package, use:

npx --yes @sstim/mcp@0.2.0

For MCP clients, set command npx and args ["--yes", "@sstim/mcp@0.2.0"]. For example, VS Code:

{
  "servers": {
    "sstim": {
      "type": "stdio",
      "command": "npx",
      "args": ["--yes", "@sstim/mcp@0.2.0"]
    }
  }
}

This is the post-publication configuration, not yet a claim that npm hosts the package. Unlike the local-checkout examples below, it requires no SSTIM source checkout. Pin an explicit package version for reproducible installations. A local checkout remains supported for development.

Publication metadata is in server.json and package.json. The official MCP Registry identity is io.github.w3c-cg/sstim, requiring an authorized publisher for the GitHub organization namespace. See distribution steps.

Prerequisites

Node.js 20+ on the machine where the AI client runs.
An SSTIM checkout for local development, for example git clone https://github.com/w3c-cg/sstim (not needed once installed from npm).
Network access to the read-only reference API (default below).
An AI client with support for local stdio MCP servers.

For each local-checkout example below, replace /absolute/path/to/sstim/packages/sstim-mcp/server.mjs with the actual absolute path to this file. On Windows, use a path like C:/Users/you/sstim/packages/sstim-mcp/server.mjs and ensure node is in the launching application's PATH.

The server is launched by the AI client. Running it manually will appear idle because it waits for JSON-RPC messages on stdin. It must not emit human-readable logs to stdout.

Four available tools

Tool	Result
`sstim_list_releases`	Supported frozen releases and latest available version
`sstim_search_concepts`	Search terms by IRI/CURIE, labels, alternatives or definition
`sstim_get_concept`	Retrieve exact term, definitions, declared relationships, source provenance
`sstim_prepare_feedback`	User-facing Contribution Bridge link; nothing is submitted

All four tools are read-only. The feedback tool generates only a link with the selected public concept ID and label, without copying conversation text. The user reviews any issue and decides whether to publish it. No writes to SSTIM occur through these tools.

Configure your software

Choose one configuration appropriate to the AI client in use. They are not interchangeable. Sample files are in examples/.

1. VS Code: GitHub Copilot Chat (Agent mode)

Create or update .vscode/mcp.json in your project using the examples/vscode.mcp.json contents:

{
  "servers": {
    "sstim": {
      "type": "stdio",
      "command": "node",
      "args": ["/absolute/path/to/sstim/packages/sstim-mcp/server.mjs"]
    }
  }
}

In VS Code run MCP: List Servers (or use MCP commands in the Command Palette), start sstim, then open GitHub Copilot Chat → Agent mode and enable the SSTIM tools in the tool picker.

This is VS Code's servers format, not the mcpServers format used by Cursor and Gemini. VS Code can also use a portable project-root .mcp.json, which has different keys; see its official MCP setup.

2. VS Code: OpenAI Codex extension / Codex CLI

Codex's IDE extension and CLI share ~/.codex/config.toml (or supported project-scoped .codex/config.toml). Append the contents of examples/codex.config.toml:

[mcp_servers.sstim]
command = "node"
args = ["/absolute/path/to/sstim/packages/sstim-mcp/server.mjs"]

Or configure the server via the Codex IDE extension: Settings → MCP servers → Add server → STDIO. Restart the extension if prompted. In the CLI, codex mcp list can show the configured servers. This configuration is separate from .vscode/mcp.json for Copilot Chat.

Reference: Codex MCP configuration.

3. VS Code: Claude Code extension / Claude Code CLI

Run in a terminal (using the same Claude Code installation as your extension):

claude mcp add --transport stdio --scope user sstim -- node /absolute/path/to/sstim/packages/sstim-mcp/server.mjs
claude mcp get sstim

Then open Claude Code (CLI or VS Code extension) and check the /mcp menu to confirm the server is connected and tools are visible. The -- separator is important: arguments after it belong to node, not to Claude's CLI. For a shared project installation instead of a personal user installation, consult the project's .mcp.json and approval rules.

Reference: Claude Code MCP setup.

4. Gemini CLI (including inside VS Code's terminal)

Add to your user ~/.gemini/settings.json or project .gemini/settings.json:

{
  "mcpServers": {
    "sstim": {
      "command": "node",
      "args": ["/absolute/path/to/sstim/packages/sstim-mcp/server.mjs"]
    }
  }
}

See examples/gemini.settings.json. Alternatively use:

gemini mcp add -s user sstim node /absolute/path/to/sstim/packages/sstim-mcp/server.mjs

Open Gemini CLI and use /mcp to inspect connectivity and exposed tools.

Gemini CLI is not the same product as the Gemini Code Assist VS Code extension. This configuration applies to the CLI; support for an extension must be verified against that extension's own settings. Reference: Gemini CLI MCP.

5. Cursor

Create a project .cursor/mcp.json, or ~/.cursor/mcp.json globally, with the contents of examples/cursor.mcp.json:

{
  "mcpServers": {
    "sstim": {
      "command": "node",
      "args": ["/absolute/path/to/sstim/packages/sstim-mcp/server.mjs"]
    }
  }
}

Open Cursor Settings → Tools & MCP and verify the server is connected. Ask Cursor Agent to use sstim_search_concepts.

Reference: Cursor MCP documentation.

6. Neovim with CodeCompanion.nvim

Neovim does not supply an AI/MCP client merely by being installed. If you use CodeCompanion.nvim, add this to its setup (or integrate the mcp table into existing config):

require("codecompanion").setup({
  mcp = {
    servers = {
      sstim = {
        cmd = { "node", "/absolute/path/to/sstim/packages/sstim-mcp/server.mjs" },
      },
    },
    opts = {
      default_servers = { "sstim" },
    },
  },
})

See examples/neovim-codecompanion.lua. Open a CodeCompanion chat and access MCP tools using the @mcp: tool group or the /mcp picker, depending on your CodeCompanion version. The plugin's MCP client currently supports the older 2025-11-25 handshake, which this server continues to accept.

For classic Vim, no built-in MCP client is assumed. You can use the Claude Code, Codex, or Gemini CLI configuration above in a terminal inside or outside Vim; do not paste Neovim Lua into a traditional .vimrc.

Verify the installation

After configuring your chosen client, ask:

Use the SSTIM MCP tools to list the current released version, search for “binaural”, and explain one matched concept using its canonical IRI and source provenance. Compare the results for v0.18.0 and v0.19.0 if applicable.

The search tools may be automatically chosen by the agent, but whether a tool is called depends on client settings and model behavior. You can also inspect the tool inventory in your host's MCP panel.

For tests inside this repository:

npm test -- --run packages/sstim-mcp/mcp.test.mjs
npm run check
npm run build

The tests exercise mocked API data, legacy and modern MCP handshakes, stdio framing, and editor-config example syntax. They do not certify interoperability with every named editor release.

Protocol versions and constraints

2026-07-28 is the current MCP protocol revision. Unlike 2025-11-25, which negotiates a process-scoped session via initialize / notifications/initialized, the new revision uses per-request metadata. This server implements both paths:

Modern clients: server/discover advertises 2026-07-28, tools are usable without initialize, and every request carries params._meta["io.modelcontextprotocol/protocolVersion"] and params._meta["io.modelcontextprotocol/clientCapabilities"]. Results declare resultType: "complete" and server identity metadata.
Older clients: continue using the legacy initialize handshake and legacy response structure. Supporting this version remains important for real installed clients, including some Neovim plugins.

The modern revision does not mean the server must be remote: stdio remains a defined transport. There is currently no Streamable HTTP endpoint for SSTIM MCP; remote ChatGPT connectors would require a separate deployment.

Protocol references: MCP 2026-07-28 versioning, stdio transport, discovery.

The latest frozen release comes from API discovery, not from a hard-coded runtime constant. At the time of this update it is v0.19.0; the separately maintained development line is v0.20.0-dev. For repeatable research use an explicit frozen release in tool arguments.

Operational limits: read-only catalog; up to 20 search results; no hosted ?q= search; no API key; no write tools; no live ontology inference, adjudication of scientific disputes, or guaranteed clinical meaning. The default reference URL is https://w3c-cg.github.io/sstim/api/v1/. An operator can override it with SSTIM_MCP_API_BASE, using HTTPS or loopback HTTP for testing. A per-process cache keeps repeated requests local until restart. Outputs retain term IRIs, release identity and source links.