from __future__ import annotations import mcp_types as types import pytest from logfire.testing import CaptureLogfire from mcp.client.client import Client from mcp.server.mcpserver import MCPServer from mcp.shared._otel import extract_trace_context pytestmark = pytest.mark.anyio def test_extract_trace_context_degrades_to_no_parent_on_malformed_traceparent() -> None: """A non-string `traceparent` makes `extract()` raise; the helper must return `None`, not propagate.""" assert extract_trace_context({"traceparent": 123}) is None async def test_client_and_server_spans(capfire: CaptureLogfire): """Verify that calling a tool produces client and server spans with correct attributes.""" server = MCPServer("test") @server.tool() def greet(name: str) -> str: """Greet someone.""" return f"Hello, {name}!" async with Client(server, mode="legacy") as client: result = await client.call_tool("greet", {"name": "World"}) assert isinstance(result.content[0], types.TextContent) assert result.content[0].text == "Hello, World!" spans = capfire.exporter.exported_spans_as_dict() span_names = {s["name"] for s in spans} assert "MCP send tools/call greet" in span_names assert "tools/call greet" in span_names client_span = next(s for s in spans if s["name"] == "MCP send tools/call greet") server_span = next(s for s in spans if s["name"] == "tools/call greet") assert client_span["attributes"]["mcp.method.name"] == "tools/call" assert server_span["attributes"]["mcp.method.name"] == "tools/call" # Server span should be in the same trace as the client span (context propagation). assert server_span["context"]["trace_id"] == client_span["context"]["trace_id"]