CoinStats MCP Server

Instructions

Implementation Reference

• src/tools/toolConfigs.ts:104-113 (schema)

  Tool configuration object defining the name, description, endpoint, HTTP method, and Zod input schema (parameters) for the 'get-coin-avg-price' tool.

  {
      name: 'get-coin-avg-price',
      description: 'Get the historical average price for a specific cryptocurrency based on its unique identifier and a specific date.',
      endpoint: '/coins/price/avg',
      method: 'GET',
      parameters: {
          coinId: z.string().describe('The identifier of coin'),
          timestamp: z.number().describe('Unix timestamp'),
      },
  },

• src/tools/toolFactory.ts:19-79 (registration)

  Registers the tool with the MCP server using server.tool(), passing the config's name, description, parameters schema, and a generic handler function that invokes universalApiHandler for API calls.

  export function registerTools(server: McpServer, toolConfigs: ToolConfig<any>[]) {
      toolConfigs.forEach((config) => {
          server.tool(config.name, config.description, config.parameters, async (params: Record<string, any>) => {
              // Handle local operations
              if (config.isLocal) {
                  // Handle specific local tools
                  if (config.name === 'save-share-token') {
                      await saveToCache('shareToken', params.shareToken);
                      return {
                          content: [
                              {
                                  type: 'text',
                                  text: 'Share token saved successfully',
                              },
                          ],
                      };
                  }
  
                  if (config.name === 'get-share-token') {
                      const shareToken = await getFromCache('shareToken');
  
                      return {
                          content: [
                              {
                                  type: 'text',
                                  text: shareToken ? shareToken : 'No share token found in cache',
                                  isError: !shareToken,
                              },
                          ],
                      };
                  }
                  // Future local tools can be added here
  
                  // Default response for unhandled local tools
                  return {
                      content: [
                          {
                              type: 'text',
                              text: 'Operation completed',
                          },
                      ],
                  };
              }
  
              // Handle API operations
              const basePath = config.basePath || COINSTATS_API_BASE;
              const method = config.method || 'GET';
  
              // Methods that typically have a request body
              const bodyMethods = ['POST', 'PUT', 'PATCH', 'DELETE'];
  
              // For GET/DELETE requests, all params go in the URL
              // For POST/PUT/PATCH, send params as the body
              if (bodyMethods.includes(method.toUpperCase())) {
                  return universalApiHandler(basePath, config.endpoint, method, {}, params);
              } else {
                  return universalApiHandler(basePath, config.endpoint, method, params);
              }
          });
      });
  }

• src/index.ts:18-18 (handler)

  Invokes registerTools on the MCP server instance with the array of all tool configurations, thereby registering 'get-coin-avg-price'.

  registerTools(server, allToolConfigs);

• src/services/request.ts:35-97 (handler)

  Core handler function that executes the HTTP request to the CoinStats API endpoint using fetch, processes parameters for path/query, adds API key header, and formats response for MCP.

  export async function universalApiHandler<T>(
      basePath: string,
      endpoint: string,
      method: string = 'GET',
      params: Record<string, any> = {},
      body?: any
  ): Promise<{
      content: Array<{ type: 'text'; text: string; isError?: boolean }>;
  }> {
      try {
          // Handle path parameters - replace {paramName} in endpoint with actual values
          let processedEndpoint = endpoint;
          let processedParams = { ...params };
  
          // Find all path parameters in the endpoint (e.g., {coinId}, {id}, {type})
          const pathParamMatches = endpoint.match(/\{([^}]+)\}/g);
  
          if (pathParamMatches) {
              for (const match of pathParamMatches) {
                  const paramName = match.slice(1, -1); // Remove { and }
  
                  if (processedParams[paramName] !== undefined) {
                      // Replace the placeholder with the actual value
                      processedEndpoint = processedEndpoint.replace(match, processedParams[paramName]);
                      // Remove the parameter from query params since it's now part of the path
                      delete processedParams[paramName];
                  } else {
                      throw new Error(`Required path parameter '${paramName}' is missing`);
                  }
              }
          }
  
          // MCP clients might not support '~' in parameter names, so we replace '-' with '~' specifically for the /coins endpoint before making the request.
          if (endpoint === '/coins') {
              processedParams = Object.entries(processedParams).reduce((acc, [key, value]) => {
                  acc[key.replace(/-/g, '~')] = value;
                  return acc;
              }, {} as Record<string, any>);
          }
  
          const url = `${basePath}${processedEndpoint}`;
          const data = await makeRequestCsApi<T>(url, method, processedParams, body);
  
          if (!data) {
              return {
                  content: [{ type: 'text', text: 'Something went wrong', isError: true }],
              };
          }
  
          return {
              content: [
                  {
                      type: 'text',
                      text: JSON.stringify(data),
                  },
              ],
          };
      } catch (error) {
          return {
              content: [{ type: 'text', text: `Error: ${error}`, isError: true }],
          };
      }
  }

• src/services/request.ts:4-32 (helper)

  Low-level HTTP request maker for CoinStats API, used by universalApiHandler.

  export async function makeRequestCsApi<T>(url: string, method: string = 'GET', params: Record<string, any> = {}, body?: any): Promise<T | null> {
      const headers = {
          'X-API-KEY': COINSTATS_API_KEY,
          'Content-Type': 'application/json',
      };
  
      try {
          // Build request options
          const options: RequestInit = { method, headers };
  
          // Add body for non-GET requests if provided
          if (method !== 'GET' && body) {
              options.body = JSON.stringify(body);
          }
  
          // Add query params for all requests
          const queryParams = new URLSearchParams(params);
          const queryString = queryParams.toString();
          const urlWithParams = queryString ? `${url}?${queryString}` : url;
  
          const response = await fetch(urlWithParams, options);
          if (!response.ok) {
              throw new Error(`HTTP error! status: ${response.status}`);
          }
          return (await response.json()) as T;
      } catch (error) {
          return null;
      }
  }