resolve_channel

Instructions

Implementation Reference

• src/index.js:190-206 (schema)

  Schema definition for the 'resolve_channel' tool, declaring its input parameter (a string 'input' for @handle, channel URL, video URL, or UC... channel ID) and description.

    name: "resolve_channel",
    description:
      "Resolve a YouTube @handle, channel URL, video URL, or raw channel ID into canonical channel info (channel ID, name, handle, subscriber count, video count, avatar). Call this first when you only have a handle or URL but need a channel ID for the other channel-scoped tools.",
    annotations: { title: "Resolve YouTube Channel", ...ANN.YT_READ },
    inputSchema: {
      type: "object",
      properties: {
        input: {
          type: "string",
          description:
            "@handle (e.g. '@MrBeast'), channel URL, video URL, or UC... channel ID. All common forms are accepted.",
          minLength: 1,
        },
      },
      required: ["input"],
    },
  },

• src/index.js:408-441 (handler)

  The callUpstream function that serves as the handler for all tools, including resolve_channel. It forwards the tool name and arguments to the upstream MCP server (api.subdownload.com/mcp) via a POST request with Bearer auth.

  async function callUpstream(name, args) {
    if (!API_KEY) {
      throw new Error(
        "SUBDOWNLOAD_API_KEY env var is not set. Get one at https://subdownload.com/account, then run with -e SUBDOWNLOAD_API_KEY=<your-key>."
      );
    }
    const res = await fetch(UPSTREAM_URL, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Accept: "application/json, text/event-stream",
        Authorization: `Bearer ${API_KEY}`,
      },
      body: JSON.stringify({
        jsonrpc: "2.0",
        id: Date.now(),
        method: "tools/call",
        params: { name, arguments: args },
      }),
    });
    const text = await res.text();
    let body;
    try {
      body = JSON.parse(text);
    } catch {
      throw new Error(
        `Upstream returned non-JSON response (HTTP ${res.status}): ${text.slice(0, 200)}`
      );
    }
    if (body.error) {
      throw new Error(body.error.message || JSON.stringify(body.error));
    }
    return body.result;
  }

• src/index.js:450-462 (registration)

  Registration of the CallToolRequestSchema handler which dispatches all tool calls (including resolve_channel) to callUpstream.

  server.setRequestHandler(CallToolRequestSchema, async (request) => {
    try {
      return await callUpstream(
        request.params.name,
        request.params.arguments || {}
      );
    } catch (err) {
      return {
        content: [{ type: "text", text: err.message || String(err) }],
        isError: true,
      };
    }
  });

• src/index.js:448-448 (registration)

  Registration of the ListToolsRequestSchema handler that returns the TOOLS array, which includes the resolve_channel tool definition.

  server.setRequestHandler(ListToolsRequestSchema, async () => ({ tools: TOOLS }));