Any MCP client – Open Context Docs

Open Context is listed in the Claude and ChatGPT catalogs, and those are the easiest paths. Every other MCP-capable client connects to the same hosted endpoint by URL.

https://mcp.opnctx.ai

That is the root of the MCP host — not a REST API path. Point your client at it directly.

Which authentication to use

	OAuth	API key
Use when	Your client can open a browser to authorize	Headless environments, or clients without OAuth support
Setup	Client opens a browser, you approve once	Generate a key, send it as a bearer token
Secret in config	None	Yes — treat the file as sensitive

Both talk to the same hosted endpoint. Prefer OAuth wherever the client supports it: nothing sensitive lands in a config file, and access is revocable from your Open Context settings.

OAuth (hosted, recommended)

Add the server

Most clients read an mcpServers block from a JSON config file. Use any stable key you like for the server name:

{
  "mcpServers": {
    "open-context": {
      "url": "https://mcp.opnctx.ai"
    }
  }
}

Restart the client

Fully quit and reopen — a window reload often isn’t enough for new MCP servers to register.

On first connect, finish sign-in at opnctx.ai and approve access. The client stores the tokens.

Verify the tools

Open your client’s MCP or tools panel and confirm Open Context tools appear — get_profile, search_library, stash_content, and the rest. See MCP tools reference.

Clients that support dynamic client registration (RFC 7591) need nothing beyond the URL. Authorization server metadata is published at the standard /.well-known endpoints on that host, so clients with discovery support configure themselves.

Open Context uses OAuth 2.0 Authorization Code flow with PKCE (RFC 7636).

API key (no browser flow)

Use this when your client can’t run a browser OAuth flow — a headless agent, a CI job, or a client without OAuth support. It connects to the same hosted endpoint; only the authentication differs.

Create an API key

In Settings → API Keys, create a key for MCP use and copy it. Keys are prefixed opnctx_.

Send it as a bearer token

The MCP endpoint accepts the key in a standard Authorization header:

Authorization: Bearer opnctx_your_key_here

How you supply that depends on the client. Many accept a headers block alongside the URL:

{
  "mcpServers": {
    "open-context": {
      "url": "https://mcp.opnctx.ai",
      "headers": {
        "Authorization": "Bearer opnctx_your_key_here"
      }
    }
  }
}

⚠️

Don’t commit API keys. If your config lives in a repo, add it to .gitignore or use a global config outside the project with per-developer keys. Revoke a leaked key from Settings → API Keys.

For a REST integration rather than MCP, the same key works against the API: Authorization: Bearer opnctx_…. See the API Reference.

Troubleshooting

Tools don’t appear. Fully quit and relaunch the client. If they still don’t show, remove the server entry, re-add it, and complete OAuth again.

Auth errors after it previously worked. Consent expired or was revoked. Disconnect the server, re-add https://mcp.opnctx.ai, and reauthorize.

Tools return empty results. Your Library may be empty — retrieval only returns what you’ve saved. Add a few items via the Chrome extension or at opnctx.ai.

Too many tools registered. Some clients cap the total tool count across all MCP servers. Disable unused tools on noisy servers so Open Context tools stay reachable.

Client-specific guides

Claude — connector directory
ChatGPT — plugin catalog
Cursor — mcp.json paths and scopes

Protocol and auth background: How it works.

Cursor How it works