Address CodeRabbit suggestions

- Add return type annotation to main() in run_with_tracing.py
- Use spread operator for argv construction
- Add type annotations to docs test example
- Use async httpx client and asyncio.sleep in diagnostics server
- Improve subprocess termination handling with timeout fallback

🤖 Generated with Claude Code

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/servers/telemetry.mdx

@@ -231,6 +231,7 @@ For testing, use the in-memory exporter:
 
 ```python
 import pytest
+from collections.abc import Generator
 from opentelemetry import trace
 from opentelemetry.sdk.trace import TracerProvider
 from opentelemetry.sdk.trace.export import SimpleSpanProcessor
@@ -239,7 +240,7 @@ from opentelemetry.sdk.trace.export.in_memory_span_exporter import InMemorySpanE
 from fastmcp import FastMCP
 
 @pytest.fixture
-def trace_exporter():
+def trace_exporter() -> Generator[InMemorySpanExporter, None, None]:
     exporter = InMemorySpanExporter()
     provider = TracerProvider()
     provider.add_span_processor(SimpleSpanProcessor(exporter))
@@ -247,7 +248,7 @@ def trace_exporter():
     yield exporter
     exporter.clear()
 
-async def test_tool_creates_span(trace_exporter):
+async def test_tool_creates_span(trace_exporter: InMemorySpanExporter) -> None:
     mcp = FastMCP("test")
 
     @mcp.tool()

examples/diagnostics/server.py

@@ -1,8 +1,8 @@
 """FastMCP Diagnostics Server - for testing tracing, errors, and observability."""
 
+import asyncio
 import os
 import subprocess
-import time
 from collections.abc import AsyncIterator
 from contextlib import asynccontextmanager
 from pathlib import Path
@@ -43,13 +43,16 @@ async def lifespan(server: FastMCP) -> AsyncIterator[None]:
         stderr=subprocess.PIPE,
     )
 
-    # Wait for server to be ready
+    # Wait for server to be ready (async to avoid blocking event loop)
-    for _ in range(50):
+    async with httpx.AsyncClient() as client:
-        try:
+        for _ in range(50):
-            httpx.get(f"http://localhost:{ECHO_SERVER_PORT}/sse", timeout=0.1)
+            try:
-            break
+                await client.get(
-        except Exception:
+                    f"http://localhost:{ECHO_SERVER_PORT}/sse", timeout=0.1
-            time.sleep(0.1)
+                )
+                break
+            except Exception:
+                await asyncio.sleep(0.1)
 
     # Mount proxy to the running echo server
     echo_proxy = create_proxy(ECHO_SERVER_URL, name="Echo Proxy")
@@ -59,7 +62,11 @@ async def lifespan(server: FastMCP) -> AsyncIterator[None]:
         yield
     finally:
         proc.terminate()
-        proc.wait(timeout=5)
+        try:
+            proc.wait(timeout=5)
+        except subprocess.TimeoutExpired:
+            proc.kill()
+            proc.wait()
 
 
 mcp = FastMCP("Diagnostics Server", lifespan=lifespan)

examples/run_with_tracing.py

@@ -19,7 +19,7 @@ import os
 import sys
 
 
-def main():
+def main() -> None:
     if len(sys.argv) < 2:
         print(__doc__)
         sys.exit(1)
@@ -51,7 +51,7 @@ def main():
     # Now run fastmcp CLI
     from fastmcp.cli.cli import app
 
-    sys.argv = ["fastmcp", "run"] + sys.argv[1:]
+    sys.argv = ["fastmcp", "run", *sys.argv[1:]]
     app()
 
 

loq.toml

@@ -288,7 +288,7 @@ max_lines = 1019
 
 [[rules]]
 path = "src/fastmcp/server/server.py"
-max_lines = 3500
+max_lines = 3000
 
 [[rules]]
 path = "tests/deprecated/test_import_server.py"