Call a Tool on an MCP Server

See more MCP Client Examples

Demonstrates Mcp.CallTool, which calls the MCP tools/call method for a named tool, passing a JSON arguments object and receiving the tool's result. The example calls the Microsoft Learn microsoft_docs_search tool.

Tip: Code to parse the returned JSON can be generated with Chilkat's online tool at https://tools.chilkat.io/jsonParse.

import { JsonObject, Mcp } from '@chilkat/react-native'

async function chilkatExample() {
  const mcp = new Mcp();

  // Connect to a public MCP (Model Context Protocol) server over its Streamable HTTP endpoint.  The
  // Microsoft Learn MCP server is public and requires no authentication.
  try {
    await mcp.connectAsync('https://learn.microsoft.com/api/mcp');
  } catch {
    console.log(mcp.lastErrorText);
    return;
  }

  // Build the tool's input arguments.  The members required depend on the tool's input schema (see
  // ListTools).  Here the Microsoft Learn "microsoft_docs_search" tool takes a search query.
  const args = new JsonObject();
  args.updateString('query', 'How do I create an Azure storage account?');

  // Call the MCP tools/call method for the named tool.  The tool's result is placed in the result
  // JsonObject.
  const result = new JsonObject();
  try {
    await mcp.callToolAsync('microsoft_docs_search', args, result);
  } catch {
    console.log(mcp.lastErrorText);
    return;
  }

  result.emitCompact = false;
  console.log(result.emit());
  // JSON parsing code for this result can be generated at Chilkat's online tool:
  // https://tools.chilkat.io/jsonParse
}