fix: add null checks for runtime.context in middlewares and tools (#1269)

Add defensive null checks before accessing runtime.context.get() to
prevent AttributeError when runtime.context is None. This affects:
- UploadsMiddleware
- MemoryMiddleware
- LoopDetectionMiddleware
- SandboxMiddleware
- sandbox tools
- setup_agent_tool
- present_file_tool
- task_tool

Also adds .env loading in serve.sh for environment variable support.

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/packages/harness/deerflow/agents/middlewares/loop_detection_middleware.py

@@ -106,7 +106,7 @@ class LoopDetectionMiddleware(AgentMiddleware[AgentState]):
 
     def _get_thread_id(self, runtime: Runtime) -> str:
         """Extract thread_id from runtime context for per-thread tracking."""
-        thread_id = runtime.context.get("thread_id")
+        thread_id = runtime.context.get("thread_id") if runtime.context else None
         if thread_id:
             return thread_id
         return "default"

backend/packages/harness/deerflow/agents/middlewares/memory_middleware.py

@@ -120,7 +120,7 @@ class MemoryMiddleware(AgentMiddleware[MemoryMiddlewareState]):
             return None
 
         # Get thread ID from runtime context
-        thread_id = runtime.context.get("thread_id")
+        thread_id = runtime.context.get("thread_id") if runtime.context else None
         if not thread_id:
             print("MemoryMiddleware: No thread_id in context, skipping memory update")
             return None

backend/packages/harness/deerflow/agents/middlewares/uploads_middleware.py

@@ -146,7 +146,7 @@ class UploadsMiddleware(AgentMiddleware[UploadsMiddlewareState]):
             return None
 
         # Resolve uploads directory for existence checks
-        thread_id = runtime.context.get("thread_id")
+        thread_id = runtime.context.get("thread_id") if runtime.context else None
         uploads_dir = self._paths.sandbox_uploads_dir(thread_id) if thread_id else None
 
         # Get newly uploaded files from the current message's additional_kwargs.files

backend/packages/harness/deerflow/sandbox/middleware.py

@@ -71,7 +71,7 @@ class SandboxMiddleware(AgentMiddleware[SandboxMiddlewareState]):
             get_sandbox_provider().release(sandbox_id)
             return None
 
-        if runtime.context.get("sandbox_id") is not None:
+        if runtime.context and runtime.context.get("sandbox_id") is not None:
             sandbox_id = runtime.context.get("sandbox_id")
             logger.info(f"Releasing sandbox {sandbox_id} from context")
             get_sandbox_provider().release(sandbox_id)

backend/packages/harness/deerflow/sandbox/tools.py

@@ -483,7 +483,7 @@ def ensure_sandbox_initialized(runtime: ToolRuntime[ContextT, ThreadState] | Non
             # Sandbox was released, fall through to acquire new one
 
     # Lazy acquisition: get thread_id and acquire sandbox
-    thread_id = runtime.context.get("thread_id")
+    thread_id = runtime.context.get("thread_id") if runtime.context else None
     if thread_id is None:
         raise SandboxRuntimeError("Thread ID not available in runtime context")
 

backend/packages/harness/deerflow/tools/builtins/present_file_tool.py

@@ -33,7 +33,7 @@ def _normalize_presented_filepath(
     if runtime.state is None:
         raise ValueError("Thread runtime state is not available")
 
-    thread_id = runtime.context.get("thread_id")
+    thread_id = runtime.context.get("thread_id") if runtime.context else None
     if not thread_id:
         raise ValueError("Thread ID is not available in runtime context")
 

backend/packages/harness/deerflow/tools/builtins/setup_agent_tool.py

@@ -24,7 +24,7 @@ def setup_agent(
         description: One-line description of what the agent does.
     """
 
-    agent_name: str | None = runtime.context.get("agent_name")
+    agent_name: str | None = runtime.context.get("agent_name") if runtime.context else None
 
     try:
         paths = get_paths()

backend/packages/harness/deerflow/tools/builtins/task_tool.py

@@ -85,7 +85,7 @@ def task_tool(
     if runtime is not None:
         sandbox_state = runtime.state.get("sandbox")
         thread_data = runtime.state.get("thread_data")
-        thread_id = runtime.context.get("thread_id")
+        thread_id = runtime.context.get("thread_id") if runtime.context else None
 
         # Try to get parent model from configurable
         metadata = runtime.config.get("metadata", {})

scripts/serve.sh

@@ -9,6 +9,13 @@ set -e
 REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 cd "$REPO_ROOT"
 
+# ── Load environment variables from .env ──────────────────────────────────────
+if [ -f "$REPO_ROOT/.env" ]; then
+    set -a
+    source "$REPO_ROOT/.env"
+    set +a
+fi
+
 # ── Argument parsing ─────────────────────────────────────────────────────────
 
 DEV_MODE=true