Fix favicon 404, clean up imports

api/server.py

@@ -6,8 +6,8 @@ from contextlib import asynccontextmanager
 
 from fastapi import FastAPI, HTTPException, Request
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import JSONResponse
-from pydantic import ValidationError
+from fastapi.responses import JSONResponse, Response
+from pydantic import BaseModel, ValidationError
 
 from env.environment import environment
 from env.models import (
@@ -30,10 +30,8 @@ _startup_time = time.time()
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
-    # Warm up — pre-load datasets and reset environment
     environment.reset(difficulty="easy")
     yield
-    # Shutdown — nothing to clean up
 
 # ─────────────────────────────────────────────
 #  APP DEFINITION
@@ -44,7 +42,7 @@ app = FastAPI(
     description = (
         "An OpenEnv-compliant reinforcement learning environment where AI agents "
         "learn to debug SQL queries across syntax errors, logic bugs, and performance issues. "
-        "Built for the META × PyTorch × SST OpenEnv Hackathon."
+        "Built for the META x PyTorch x SST OpenEnv Hackathon."
     ),
     version     = "1.0.0",
     lifespan    = lifespan,
@@ -73,17 +71,23 @@ async def global_exception_handler(request: Request, exc: Exception):
     )
 
 
+# ─────────────────────────────────────────────
+#  FAVICON — fix 404
+# ─────────────────────────────────────────────
+
+@app.get("/favicon.ico", include_in_schema=False)
+async def favicon():
+    """Returns 204 No Content instead of 404 for favicon requests."""
+    return Response(status_code=204)
+
+
 # ─────────────────────────────────────────────
 #  1. /health — GET
-#  Must always return 200 even if env not initialized
 # ─────────────────────────────────────────────
 
 @app.get("/health", response_model=HealthResponse, tags=["System"])
 async def health():
-    """
-    Liveness check. Always returns 200.
-    Used by HF Space health monitoring.
-    """
+    """Liveness check. Always returns 200. Used by HF Space health monitoring."""
     return HealthResponse(
         status  = "ok",
         version = "1.0.0",
@@ -93,14 +97,8 @@ async def health():
 
 # ─────────────────────────────────────────────
 #  2. /reset — POST
-#  Starts new episode, returns Observation
 # ─────────────────────────────────────────────
 
-class ResetRequest(Action.__class__):
-    pass
-
-from pydantic import BaseModel
-
 class ResetBody(BaseModel):
     difficulty: Optional[str] = None
     task_id:    Optional[str] = None
@@ -108,9 +106,7 @@ class ResetBody(BaseModel):
 @app.post("/reset", response_model=Observation, tags=["Environment"])
 async def reset(body: ResetBody = ResetBody()):
     """
-    Starts a fresh episode.
-    Returns the initial Observation the agent sees.
-
+    Starts a fresh episode. Returns the initial Observation the agent sees.
     Edge case: always returns valid Observation even if dataset issues occur.
     """
     try:
@@ -127,7 +123,6 @@ async def reset(body: ResetBody = ResetBody()):
 
 # ─────────────────────────────────────────────
 #  3. /step — POST
-#  Accepts Action, returns StepResponse
 # ─────────────────────────────────────────────
 
 @app.post("/step", response_model=StepResponse, tags=["Environment"])
@@ -135,21 +130,16 @@ async def step(action: Action):
     """
     Submits an action to the environment.
     Returns (observation, reward, done, info).
-
-    Edge cases:
-    - Invalid/malformed action → reward=-0.1, done=False
-    - Episode already done → returns terminal state
-    - Null payload → graceful penalty
+    Edge cases: null action, malformed payload, episode already done.
     """
     try:
         response = environment.step(action)
         return response
     except ValidationError as e:
-        # Malformed action — return penalty reward, never crash
-        obs = environment.state()
+        from env.models import Reward
         return StepResponse(
             observation = environment._build_observation(),
-            reward      = __import__("env.models", fromlist=["Reward"]).Reward(
+            reward      = Reward(
                 score     = -0.1,
                 breakdown = {"validation_error": -0.1},
                 feedback  = f"Malformed action: {str(e)}"
@@ -163,7 +153,6 @@ async def step(action: Action):
 
 # ─────────────────────────────────────────────
 #  4. /state — GET
-#  Returns current environment state
 # ─────────────────────────────────────────────
 
 @app.get("/state", response_model=EpisodeState, tags=["Environment"])
@@ -171,14 +160,13 @@ async def state():
     """
     Returns full current environment state.
     Works before reset() is called — returns default empty state.
-    Must always be JSON-serializable.
+    Always JSON-serializable. Never crashes.
     """
     return environment.state()
 
 
 # ─────────────────────────────────────────────
 #  5. /tasks — GET
-#  Lists all tasks + action schema
 # ─────────────────────────────────────────────
 
 @app.get("/tasks", response_model=TaskListResponse, tags=["Tasks"])
@@ -197,28 +185,22 @@ async def tasks():
 
 # ─────────────────────────────────────────────
 #  6. /grader — POST
-#  Grades a completed episode
 # ─────────────────────────────────────────────
 
 @app.post("/grader", response_model=GraderResponse, tags=["Grading"])
 async def grader(request: GraderRequest):
     """
-    Grades a completed episode.
-    Returns float score between 0.0 and 1.0.
-
-    Edge cases:
-    - Null/empty episode → returns 0.0, never crashes
-    - Unknown task_id → returns 0.0 with explanation
+    Grades a completed episode action.
+    Returns float score 0.0-1.0. Never crashes.
+    Edge cases: null action → 0.0, unknown task → 0.0.
     """
     try:
-        # Edge case: null action in request
         if request.action is None:
             return GraderResponse(
                 score     = 0.0,
                 feedback  = "No action provided for grading.",
                 breakdown = {"error": "null_action"}
             )
-
         score, breakdown, feedback = grade(request.action, request.task_id)
         return GraderResponse(
             score     = score,
@@ -226,7 +208,6 @@ async def grader(request: GraderRequest):
             breakdown = breakdown
         )
     except Exception as e:
-        # Never crash — return 0.0
         return GraderResponse(
             score     = 0.0,
             feedback  = f"Grader error: {str(e)}",
@@ -236,8 +217,6 @@ async def grader(request: GraderRequest):
 
 # ─────────────────────────────────────────────
 #  7. /baseline — POST
-#  Runs baseline inference, returns scores
-#  Must complete within 60 seconds
 # ─────────────────────────────────────────────
 
 @app.post("/baseline", response_model=BaselineResponse, tags=["Baseline"])
@@ -245,38 +224,45 @@ async def baseline():
     """
     Runs the baseline agent against all 3 difficulty levels.
     Returns scores JSON. Must complete within 60 seconds.
-
-    Edge case: OPENAI_API_KEY not set → returns error scores without crashing.
+    Edge case: OPENAI_API_KEY not set → continues with rule-based agent.
     """
     try:
-        # Import here to avoid circular imports
         import baseline as baseline_module
         results = await asyncio.wait_for(
             asyncio.to_thread(baseline_module.run_baseline),
-            timeout=55.0  # 5s buffer before 60s limit
+            timeout=55.0
         )
         return results
     except asyncio.TimeoutError:
-        # Return partial results on timeout
         return BaselineResponse(
             results=[
-                BaselineResult(task_id="timeout", difficulty=DifficultyLevel.EASY,
-                               score=0.0, steps=0, feedback="Baseline timed out after 55 seconds.")
+                BaselineResult(
+                    task_id    = "timeout",
+                    difficulty = DifficultyLevel.EASY,
+                    score      = 0.0,
+                    steps      = 0,
+                    feedback   = "Baseline timed out after 55 seconds."
+                )
             ],
             average_score=0.0
         )
     except Exception as e:
         return BaselineResponse(
             results=[
-                BaselineResult(task_id="error", difficulty=DifficultyLevel.EASY,
-                               score=0.0, steps=0, feedback=f"Baseline error: {str(e)}")
+                BaselineResult(
+                    task_id    = "error",
+                    difficulty = DifficultyLevel.EASY,
+                    score      = 0.0,
+                    steps      = 0,
+                    feedback   = f"Baseline error: {str(e)}"
+                )
             ],
             average_score=0.0
         )
 
 
 # ─────────────────────────────────────────────
-#  ROOT — redirect to docs
+#  ROOT — project info
 # ─────────────────────────────────────────────
 
 @app.get("/", tags=["System"])
@@ -287,7 +273,7 @@ async def root():
         "docs":        "/docs",
         "health":      "/health",
         "endpoints":   ["/reset", "/step", "/state", "/tasks", "/grader", "/baseline", "/health"],
-        "hackathon":   "META × PyTorch × SST OpenEnv Hackathon",
+        "hackathon":   "META x PyTorch x SST OpenEnv Hackathon",
         "domain":      "SQL Query Debugging",
         "tasks_count": 15,
     }