Publish and invoke tools

MCP tools let AI agents execute actions on the server via two endpoints:

• tools/list: Discovers available tool schemas.
• tools/call: Invokes a tool with specific parameters.

Mental Model: Tool Manifest and Invocation

1. Manifest (tools/list):
   • "add": Takes numbers a and b.
   • "echo": Takes string text.
2. Invocation (tools/call):
   • Evaluates arguments and returns results in a content array with isError: false.

Your Goal in this Stage

Implement tools/list for schema discovery and tools/call for execution.

Input Format (tools/list)

{ "jsonrpc": "2.0", "id": 3, "method": "tools/list" }

Output Format (tools/list)

{
  "jsonrpc": "2.0",
  "id": 3,
  "result": {
    "tools": [
      {
        "name": "add",
        "description": "Add two numbers",
        "inputSchema": {
          "type": "object",
          "properties": {
            "a": { "type": "number" },
            "b": { "type": "number" }
          },
          "required": ["a", "b"],
          "additionalProperties": false
        }
      },
      {
        "name": "echo",
        "description": "Echo text",
        "inputSchema": {
          "type": "object",
          "properties": { "text": { "type": "string" } },
          "required": ["text"],
          "additionalProperties": false
        }
      }
    ]
  }
}

Input Format (tools/call)

{
  "jsonrpc": "2.0",
  "id": 4,
  "method": "tools/call",
  "params": { "name": "add", "arguments": { "a": 2.5, "b": 4 } }
}

Output Format (tools/call)

{
  "jsonrpc": "2.0",
  "id": 4,
  "result": { "content": [{ "type": "text", "text": "6.5" }], "isError": false }
}

Step-by-Step Implementation Guide

1. Handle "tools/list": Return catalog with add and echo tool schemas.
2. Handle "tools/call":
   • For add: add numbers and stringify sum.
   • For echo: stringify text argument.
3. Emit output: Print JSON response with matching id.

Acceptance Criteria

• ✅ Discloses add and echo schemas.
• ✅ Correctly executes tool requests.

Multiline examples are formatted for readability. Emit compact JSON without optional spaces, with properties in the order shown by the output examples, and a final newline. Keep logs off stdout. Tests compare exact text.