fix(gateway): merge context field into configurable for langgraph-compat runs (#1699) (#1707)

The langgraph-compat layer dropped the DeerFlow-specific `context` field
from run requests, causing agent config (subagent_enabled, is_plan_mode,
thinking_enabled, etc.) to fall back to defaults. Add `context` to
RunCreateRequest and merge allowlisted keys into config.configurable in
start_run, with existing configurable values taking precedence.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/gateway/routers/thread_runs.py

@@ -38,6 +38,7 @@ class RunCreateRequest(BaseModel):
     command: dict[str, Any] | None = Field(default=None, description="LangGraph Command")
     metadata: dict[str, Any] | None = Field(default=None, description="Run metadata")
     config: dict[str, Any] | None = Field(default=None, description="RunnableConfig overrides")
+    context: dict[str, Any] | None = Field(default=None, description="DeerFlow context overrides (model_name, thinking_enabled, etc.)")
     webhook: str | None = Field(default=None, description="Completion callback URL")
     checkpoint_id: str | None = Field(default=None, description="Resume from checkpoint")
     checkpoint: dict[str, Any] | None = Field(default=None, description="Full checkpoint object")

backend/app/gateway/services.py

@@ -271,6 +271,27 @@ async def start_run(
     agent_factory = resolve_agent_factory(body.assistant_id)
     graph_input = normalize_input(body.input)
     config = build_run_config(thread_id, body.config, body.metadata, assistant_id=body.assistant_id)
+
+    # Merge DeerFlow-specific context overrides into configurable.
+    # The ``context`` field is a custom extension for the langgraph-compat layer
+    # that carries agent configuration (model_name, thinking_enabled, etc.).
+    # Only agent-relevant keys are forwarded; unknown keys (e.g. thread_id) are ignored.
+    context = getattr(body, "context", None)
+    if context:
+        _CONTEXT_CONFIGURABLE_KEYS = {
+            "model_name",
+            "mode",
+            "thinking_enabled",
+            "reasoning_effort",
+            "is_plan_mode",
+            "subagent_enabled",
+            "max_concurrent_subagents",
+        }
+        configurable = config.setdefault("configurable", {})
+        for key in _CONTEXT_CONFIGURABLE_KEYS:
+            if key in context:
+                configurable.setdefault(key, context[key])
+
     stream_modes = normalize_stream_modes(body.stream_mode)
 
     task = asyncio.create_task(