Ankr API MCP Server

Instructions

Implementation Reference

• src/tools/tokens.ts:55-114 (handler)

  The core handler function that executes the tool logic: fetches token balances from Ankr API for a wallet address on a specific network, handles authentication, API calls, and various error conditions.

  export async function getTokenBalancesOnNetwork(
    network: string,
    address: string
  ): AssetsResponse {
  
    const token = process.env.ANKR_API_TOKEN
    const endpoint = `https://rpc.ankr.com/multichain/${token}`;
   // console.log(JSON.stringify(endpoint));
  
    if (!token) {
      throw new AnkrAuthenticationError('ANKR_API_TOKEN environment variable is not set');
    }
  
  
  
    try {
  
      const data = {
        jsonrpc: "2.0",
        method: "ankr_getAccountBalance",
        params: {
          blockchain: network,
          walletAddress: address
        },
        id: 1
      };
  
      const response = await axios.post(
        endpoint,
        data,
        {
          headers: {
            'Content-Type': 'application/json',
          },
  
        }
      );
  
      return response.data;
    } catch (error) {
      if (axios.isAxiosError(error)) {
        const statusCode = error.response?.status || 'unknown';
        const errorMessage = error.response?.data?.message || error.message;
        if (statusCode === 401 || statusCode === 403) {
          throw new AnkrAuthenticationError(`Authentication Failed: ${errorMessage}`);
        } else if (statusCode === 404) {
          throw new AnkrResourceNotFoundError(`Address or network not found: ${address} on ${network}`);
        } else if (statusCode === 422) {
          throw new AnkrValidationError(`Validation Error: ${errorMessage}`, error.response?.data);
        } else if (statusCode === 429) {
          const resetAt = new Date();
          resetAt.setSeconds(resetAt.getSeconds() + 60);
          throw new AnkrRateLimitError(`Rate Limit Exceeded: ${errorMessage}`, resetAt);
        }
        
        throw new Error(`Ankr API Error (${statusCode}): ${errorMessage}`);
      }
      throw new Error(`Failed to get token balances: ${error instanceof Error ? error.message : String(error)}`);
    }
  }

• src/tools/tokens.ts:40-43 (schema)

  Zod schema defining the input parameters for the tool: network and address.

  export const TokenBalancesOnNetworkSchema = z.object({
    network: z.string().describe('The blockchain network (e.g., "ethereum", "base")'),
    address: z.string().describe('The address to check token balances for')
  });

• src/index.ts:38-45 (registration)

  Tool registration in the ListTools handler, specifying name, description, and input schema.

  tools: [
      // Token Tools
      {
          name: "get_token_balances_on_network",
          description: "Gets all token balances for a given address on a specific network",
          inputSchema: zodToJsonSchema(tokens.TokenBalancesOnNetworkSchema)
      }
  ]

• src/index.ts:56-65 (registration)

  Tool dispatch registration in the CallTool handler: validates input with schema and invokes the handler function.

  case "get_token_balances_on_network": {
      const args = tokens.TokenBalancesOnNetworkSchema.parse(request.params.arguments);
      const result = await tokens.getTokenBalancesOnNetwork(
          args.network,
          args.address
      );
      return {
          content: [{type: "text", text: JSON.stringify(result, null, 2)}],
      };
  }