NASA MCP Server

Instructions

Implementation Reference

• src/handlers/jpl/cad.ts:14-80 (handler)

  The `cadHandler` function implements the core logic for the "jpl_cad" tool. It calls the JPL CAD API with transformed parameters, processes the response, creates descriptive resource URIs (jpl://cad/...), adds the JSON data as a resource, and returns formatted content.
  export async function cadHandler(args: Record<string, any>) { try { // Base URL for the CAD API const baseUrl = 'https://ssd-api.jpl.nasa.gov/cad.api'; // Validate parameters if needed // Parameters are fairly flexible in this API, so minimal validation is needed // Transform parameter names from underscore to hyphenated format const transformedParams = transformParamsToHyphenated(args); // Make the API request const response = await axios.get(baseUrl, { params: transformedParams }); const data = response.data; // Create a resource URI that represents this query let resourceUri: string; let resourceName: string; if (args.des) { // Query for a specific object resourceUri = `jpl://cad/object/${args.des}`; resourceName = `Close approaches for object ${args.des}`; } else if (args.spk) { // Query for a specific object by SPK-ID resourceUri = `jpl://cad/object/${args.spk}`; resourceName = `Close approaches for object ${args.spk}`; } else { // Query for close approaches with constraints const constraints = Object.entries(args) .map(([key, value]) => `${key}=${value}`) .join('&'); resourceUri = `jpl://cad/list${constraints ? '?' + constraints : ''}`; // Create a readable name based on date range and body const dateMin = args['date_min'] || 'now'; const dateMax = args['date_max'] || '+60'; const body = args.body || 'Earth'; resourceName = `Close approaches to ${body} from ${dateMin} to ${dateMax}`; } // Add response to resources addResource(resourceUri, { name: resourceName, mimeType: "application/json", text: JSON.stringify(data, null, 2) }); // Format the response return { content: [{ type: "text", text: JSON.stringify(data, null, 2) }] }; } catch (error: any) { return { content: [{ type: "text", text: `Error accessing JPL SB Close Approach API: ${error.message}` }], isError: true }; } }
• src/index.ts:1133-1180 (schema)

  Input schema definition for the "jpl_cad" tool in the tools/list handler response, specifying all parameters with types and descriptions matching the JPL CAD API.
  name: "jpl_cad", description: "Asteroid and comet close approaches to the planets in the past and future", inputSchema: { type: "object", properties: { "dist_max": { type: "string", description: "Maximum approach distance (e.g., 0.05, 10LD). Default: 0.05 au" }, "dist_min": { type: "string", description: "Minimum approach distance. Default: none" }, "date_min": { type: "string", description: "Start date for search (YYYY-MM-DD). Default: now" }, "date_max": { type: "string", description: "End date for search (YYYY-MM-DD). Default: +60 days" }, "body": { type: "string", description: "Body to find close approaches to (e.g., Earth, Mars, ALL). Default: Earth" }, "sort": { type: "string", description: "Sort field: date, dist, dist-min, v-inf, v-rel, h, object. Default: date" }, "des": { type: "string", description: "Object designation (e.g., '2000 SG344' or '433')" }, "spk": { type: "string", description: "Object SPK-ID (e.g., '2000433')" }, "neo": { type: "boolean", description: "Limit to NEOs. Default: true" }, "fullname": { type: "boolean", description: "Include full object name in result. Default: false" } } } },
• src/index.ts:523-526 (registration)

  Registers the "jpl_cad" tool in the tools/manifest response with its ID and description.
  name: "jpl_cad", id: "jpl/cad", description: "Asteroid and comet close approaches to the planets in the past and future" },
• src/index.ts:1896-1932 (registration)

  Dynamic registration and dispatch logic in `handleToolCall` for all JPL tools, including "jpl/cad". Dynamically imports `./handlers/jpl/cad.js` and calls the exported handler function (cadHandler).
  } else if (internalToolId.startsWith("jpl/")) { // Extract the JPL API endpoint name const endpoint = internalToolId.split("/")[1]; serverInstance?.sendLoggingMessage({ level: "info", data: `JPL Endpoint: ${endpoint}`, }); try { // Dynamic import for JPL handlers using the original slash format path serverInstance?.sendLoggingMessage({ level: "info", data: `Importing handler module: ./handlers/jpl/${endpoint}.js`, }); const handlerModule = await import(`./handlers/jpl/${endpoint}.js`); // Try to find the handler function in various export formats const handlerFunction = handlerModule.default || handlerModule[`jpl${endpoint.charAt(0).toUpperCase() + endpoint.slice(1)}Handler`] || handlerModule[`${endpoint}Handler`]; if (typeof handlerFunction === 'function') { return await handlerFunction(args); } else { throw new Error(`Handler for ${endpoint} not found in module`); } } catch (error: unknown) { const errorMessage = error instanceof Error ? error.message : String(error); return { content: [{ type: "text", text: `Error executing JPL tool '${toolName}': ${errorMessage}` }], isError: true }; } }
• src/handlers/jpl/cad.ts:22-22 (helper)

  Imports the `transformParamsToHyphenated` helper used in cadHandler to convert underscore params to hyphenated for the API.
  // Transform parameter names from underscore to hyphenated format
• src/index.ts:2126-2132 (registration)

  Global registration of 'mcp__jplcad' tool that forwards to the main jpl/cad handler.
  registerGlobalTool('mcp__jplcad', async (args: Record<string, any>) => { serverInstance?.sendLoggingMessage({ level: "info", data: `MCP JPL CAD called with args: ${JSON.stringify(args)}`, }); return await handleToolCall('jpl/cad', args); });