fix: add validation logging and debug info for tool instance creation

- Add RequestValidationError handler to log validation errors
- Add extra=ignore to CreateInstanceRequest to be more lenient
- Add logging to create_instance endpoint to see received data
- Add missing logger import in tool_instances.py

apps/api/src/main.py

@@ -1,8 +1,10 @@
 import logging
 import os
 
-from fastapi import FastAPI
+from fastapi import FastAPI, Request
+from fastapi.exceptions import RequestValidationError
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import JSONResponse
 from fastapi.staticfiles import StaticFiles
 from sqlalchemy import select, text
 
@@ -48,6 +50,22 @@ app.add_middleware(RequestLoggingMiddleware)
 app.add_middleware(ExceptionLoggingMiddleware)
 
 
+@app.exception_handler(RequestValidationError)
+async def validation_exception_handler(request: Request, exc: RequestValidationError):
+    """Log validation errors and return detailed response."""
+    errors = exc.errors()
+    logger.warning(
+        "Validation error for %s %s: %s",
+        request.method,
+        request.url.path,
+        errors,
+    )
+    return JSONResponse(
+        status_code=422,
+        content={"detail": errors},
+    )
+
+
 async def _table_exists(session, table_name: str) -> bool:
     """Check if a table exists in the database."""
     try: