# Using MCP Tools Inside Your Own Agent — MCP & Agent-to-Agent Protocols

Source: https://www.geekswithgeeks.com/en/mcp-a2a/c-agent-use

> Bridge MCP tool definitions into an agent loop.

## List, convert, call, return

When you build your own host or agent, the loop is: connect and initialise; `tools/list`; **convert** each MCP tool (name, description, `inputSchema`) into your model API's tool format (the JSON Schema usually maps directly); send the user message with those tools; when the model returns a tool call, run **policy checks**, call `tools/call` on the right session, convert the content result back into a tool-result message and continue until the model answers. Many agent frameworks (LangChain, LangGraph, the OpenAI and Anthropic agent SDKs and others) ship **MCP adapters** that do this conversion, but the responsibilities remain yours: approvals, limits, logging and error handling.

## The agent-side loop (pseudocode)

Frameworks wrap this; knowing it helps with debugging. Illustrative; not run here.

```python
tools = mcp_session.list_tools()                       # tools/list (follow pagination)
model_tools = [{"name": t.name, "description": t.description,
                "input_schema": t.inputSchema} for t in tools]

messages = [user_message]
for step in range(MAX_STEPS):                                # always cap the loop
    reply = model.call(messages, tools=model_tools)
    if not reply.tool_calls:
        return reply.text
    for call in reply.tool_calls:
        ok, why = authorize(call.name, call.args)             # your policy / approval layer
        result = mcp_session.call_tool(call.name, call.args) if ok else {"error": why}
        messages.append(tool_result_message(call.id, result))
```

**Quiz:** What do MCP adapters in agent frameworks NOT do for you?

- [ ] List tools
- [ ] Convert tool schemas
- [x] Decide your approval policy, limits and logging
- [ ] Forward calls to a server

*Answer:* Decide your approval policy, limits and logging. Safety and governance remain the application's responsibility.