RSS3 MCP Server

Instructions

Implementation Reference

• index.js:150-223 (handler)

  Generic handler for executing all dynamically generated API tools, including "API-getChipById". Locates the corresponding OpenAPI operation via name lookup and invokes it using the HttpClient, returning JSON-stringified response or error.

  server.setRequestHandler(CallToolRequestSchema, async (request) => {
  	// console.error("call tool", request.params);
  	const { name, arguments: params } = request.params;
  
  	console.error("name", name);
  
  	if (name === "API-get-input-schema") {
  		for (const mcpToolWithClient of mcpToolWithClients) {
  			for (const [toolName, def] of Object.entries(
  				mcpToolWithClient.mcpTools.tools,
  			)) {
  				for (const method of def.methods) {
  					const toolNameWithMethod = `${toolName}-${method.name}`;
  					const truncatedToolName = toolNameWithMethod.slice(0, 64);
  					if (truncatedToolName === params.toolName) {
  						return {
  							content: [
  								{ type: "text", text: JSON.stringify(method.inputSchema) },
  							],
  						};
  					}
  				}
  			}
  		}
  		throw new Error(`Method ${params.toolName} not found`);
  	}
  
  	// find operation
  	const mcpToolWithClient = mcpToolWithClients.find(
  		(t) => t.mcpTools.openApiLookup[name],
  	);
  	if (!mcpToolWithClient) {
  		throw new Error(`Method ${name} not found`);
  	}
  
  	const operation = mcpToolWithClient.mcpTools.openApiLookup[name];
  
  	// execute
  	try {
  		const response = await mcpToolWithClient.client.executeOperation(
  			operation,
  			params,
  		);
  		return {
  			content: [
  				{
  					type: "text", // currently this is the only type that seems to be used by mcp server
  					text: JSON.stringify(response.data), // TODO: pass through the http status code text?
  				},
  			],
  		};
  	} catch (error) {
  		console.error("Error in tool call", error);
  		if (error instanceof HttpClientError) {
  			console.error(
  				"HttpClientError encountered, returning structured error",
  				error,
  			);
  			const data = error.data?.response?.data ?? error.data ?? {};
  			return {
  				content: [
  					{
  						type: "text",
  						text: JSON.stringify({
  							status: "error", // TODO: get this from http status code?
  							...(typeof data === "object" ? data : { data: data }),
  						}),
  					},
  				],
  			};
  		}
  		throw error;
  	}
  });

• index.js:100-147 (registration)

  Dynamic tool registration via listing handler. Generates tool list from OpenAPI specs converted to MCP tools, constructing names like `${toolName}-${method.name}` (truncated), including "API-getChipById" if defined in the fetched OpenAPI.

  server.setRequestHandler(ListToolsRequestSchema, async () => {
  	console.error("list tools");
  	/**
  	 * @typedef {import("@modelcontextprotocol/sdk/types.js").Tool} Tool
  	 * @type {Tool[]}
  	 */
  	const tools = [];
  
  	for (const mcpToolWithClient of mcpToolWithClients) {
  		for (const [toolName, def] of Object.entries(
  			mcpToolWithClient.mcpTools.tools,
  		)) {
  			for (const method of def.methods) {
  				console.error("method", method);
  				const toolNameWithMethod = `${toolName}-${method.name}`;
  				const truncatedToolName = toolNameWithMethod.slice(0, 64);
  				const trimmedDescription = method.description.split("Error")[0].trim();
  				tools.push({
  					name: truncatedToolName,
  					description: trimmedDescription,
  					inputSchema: {
  						type: "object",
  						properties: {},
  					},
  				});
  			}
  		}
  	}
  
  	tools.unshift({
  		name: "API-get-input-schema",
  		description:
  			"Get the input schema for a given API. We should always use this tool to get the input schema for a given API before calling the API.",
  		inputSchema: {
  			type: "object",
  			properties: {
  				toolName: {
  					type: "string",
  					description: "The name of the tool to get the input schema for",
  				},
  			},
  		},
  	});
  
  	console.error("tools", tools);
  
  	return { tools };
  });

• index.js:156-175 (schema)

  Schema retrieval logic within the tool handler. The special tool 'API-get-input-schema' returns the input schema for any API tool like "API-getChipById" by matching the tool name to OpenAPI method schemas.

  if (name === "API-get-input-schema") {
  	for (const mcpToolWithClient of mcpToolWithClients) {
  		for (const [toolName, def] of Object.entries(
  			mcpToolWithClient.mcpTools.tools,
  		)) {
  			for (const method of def.methods) {
  				const toolNameWithMethod = `${toolName}-${method.name}`;
  				const truncatedToolName = toolNameWithMethod.slice(0, 64);
  				if (truncatedToolName === params.toolName) {
  					return {
  						content: [
  							{ type: "text", text: JSON.stringify(method.inputSchema) },
  						],
  					};
  				}
  			}
  		}
  	}
  	throw new Error(`Method ${params.toolName} not found`);
  }

• index.js:78-84 (helper)

  Helper that converts OpenAPI specifications to MCP tool definitions and associates them with HttpClient instances. This generates the openApiLookup and tools used for name resolution and execution of API tools like "API-getChipById".

  const mcpToolWithClients = converterWithClients.map((cwc) => {
  	const mcpTools = cwc.converter.convertToMCPTools();
  	return {
  		mcpTools,
  		client: cwc.client,
  	};
  });

• index.js:40-70 (helper)

  Loads OpenAPI specifications from RSS3 endpoints and initializes HttpClient instances. These specs define the operations for tools like "API-getChipById".

  const openApiSpecs = (
  	await Promise.allSettled([
  		fetch("https://gi.rss3.io/docs/openapi.json").then(async (res) => {
  			if (!res.ok) throw new Error(`HTTP error! status: ${res.status}`);
  			return res.json();
  		}),
  		fetch("https://ai.rss3.io/openapi.json").then(async (res) => {
  			if (!res.ok) throw new Error(`HTTP error! status: ${res.status}`);
  			return res.json();
  		}),
  	]).then((results) => {
  		return results.map((result) => {
  			if (result.status === "fulfilled") {
  				const client = new HttpClient(
  					{
  						baseUrl: result.value.servers[0].url,
  					},
  					result.value,
  				);
  				return {
  					spec: result.value,
  					client,
  				};
  			}
  
  			console.error("Failed to fetch openapi spec", result.reason);
  			return null;
  		});
  	})
  ).filter(Boolean);