MCP

claude mcp add --transport http crabtalk https://mcp.crabtalk.ai \
  --header "Authorization: Bearer ck_…"

https://mcp.crabtalk.ai serves every service over MCP, Streamable HTTP. Its tools never change, so a client added once reaches every service, including ones deployed later.

• Auth: an API key as Authorization: Bearer. Calls are made as the key's account and reach what its calls over HTTP reach.
• search takes query, a service address, catalog job or category, or words for what a tool does, and answers the services that match, best first, with their public tools and each tool's price. A service is found once it has been deployed.
• crab://{service} is a resource, the service named owner/name as search names it: its README, then its IDL, which has each public tool's description and arguments.
• call takes service (owner/name), tool and input, the tool's arguments. It answers the tool's result, or the message of a tool that failed or a call that was refused.
• A tool with a price charges it to the key's account, as a call over HTTP does. See Calling a tool.

REST and MCP tool calls share the key account's execution quota. See Request limits for rates, concurrency and HTTP/MCP retry responses.

Developing a service for agents to find? See Service catalog for tool classification and searchable descriptions.

Clients that take a URL

Cursor, and any client configured with JSON:

{
  "mcpServers": {
    "crabtalk": {
      "url": "https://mcp.crabtalk.ai",
      "headers": { "Authorization": "Bearer ck_…" }
    }
  }
}

Connectors

claude.ai, ChatGPT and other clients that sign in with OAuth take the URL alone. The host manages this connection independently of the crab CLI.

1. Open an existing CrabTalk connection, or add https://mcp.crabtalk.ai as a remote MCP server with OAuth authentication in your host.
2. Complete sign-in if needed. The client opens a CrabTalk approval page showing its name, your account, management permissions and a daily budget. It initially requests no management permissions and a $5 budget; review or change these before approving.
3. Make the connection's tools available in the active conversation. In ChatGPT, install the resulting plugin, then start a new conversation and select it with @. See ChatGPT's connection guide.
4. Call search with {"query":"<what you need to do>"}, replacing the query with the task. A successful authenticated result, including an empty list, verifies the connection.

Approval issues a dedicated API key for that connection. Manage its permissions, priced-service grants, budget, usage and revocation under Settings → API keys. The secret is delivered directly to the client.

Connection problems

• HTTP 401 without credentials is the OAuth discovery challenge. It does not establish whether an existing host connection is authorized.
• If the URL is configured but tools are unavailable, check the host's connection status, sign-in, plugin installation and availability in the conversation. After a server metadata change, refresh the host connection.
• If the agent cannot configure MCP or start sign-in through its host, report that missing capability and the action the person must take. With shell access, the agent can separately set up CLI access.

Report MCP setup as complete only after an authenticated search succeeds. Otherwise report the failed step and returned error.

The local host serves its own MCP endpoint: see Local host.