diff --git a/main.py b/main.py
index fb2733c47..1fe7db3f7 100644
--- a/main.py
+++ b/main.py
@@ -16,6 +16,7 @@ from fastapi import FastAPI, Response, Depends, HTTPException, status
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import RedirectResponse, StreamingResponse, HTMLResponse, JSONResponse
 from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
+from typing import Optional
 from pydantic import BaseModel
 from dotenv import load_dotenv
 import httpx
@@ -118,7 +119,9 @@ def log_error(error: Exception, context: dict) -> dict:
 
 
 class ChatRequest(BaseModel):
-    query: str
+    query: Optional[str] = None
+    message: Optional[str] = None
+    session_id: Optional[str] = None
     history: list[dict] = []
     # Clients must echo back pending_write from the previous response when
     # the user is confirming (or cancelling) a write operation.
@@ -128,6 +131,10 @@ class ChatRequest(BaseModel):
     # on the caller's own portfolio data instead of the shared env-var token.
     bearer_token: str | None = None
 
+    def get_text(self) -> str:
+        """Accept either field name for backwards compatibility."""
+        return (self.query or self.message or "").strip()
+
 
 class FeedbackRequest(BaseModel):
     query: str
@@ -141,6 +148,23 @@ async def chat(req: ChatRequest, gf_token: str = Depends(require_auth)):
     start_time = time.time()
     trace_id = str(uuid.uuid4())
 
+    user_text = req.get_text()
+    if not user_text:
+        return {
+            "error": "No message provided",
+            "response": "Please send a message.",
+            "confidence": 0.0,
+            "verified": False,
+            "latency_ms": int((time.time() - start_time) * 1000),
+            "trace_id": trace_id,
+            "tokens": {
+                "estimated_input": 0,
+                "estimated_output": 0,
+                "estimated_total": 0,
+                "estimated_cost_usd": 0.0,
+            },
+        }
+
     # Build conversation history preserving both user AND assistant turns so
     # Claude has full context for follow-up questions.
     history_messages = []
@@ -179,7 +203,7 @@ async def chat(req: ChatRequest, gf_token: str = Depends(require_auth)):
         log_error(
             e,
             {
-                "message": req.query[:200],
+                "message": user_text[:200],
                 "session_id": None,
                 "query_type": "unknown",
             },
@@ -205,7 +229,7 @@ async def chat(req: ChatRequest, gf_token: str = Depends(require_auth)):
 
     cost_log.append({
         "timestamp": datetime.utcnow().isoformat(),
-        "query": req.query[:80],
+        "query": user_text[:80],
         "estimated_cost_usd": round(COST_PER_REQUEST_USD, 5),
         "latency_seconds": elapsed,
     })
@@ -328,6 +352,7 @@ async def chat_stream(req: ChatRequest, gf_token: str = Depends(require_auth)):
     Runs the full graph, then streams the final response word by word so
     the user sees output immediately rather than waiting for the full response.
     """
+    user_text = req.get_text()
 
     history_messages = []
     for m in req.history:
@@ -339,7 +364,7 @@ async def chat_stream(req: ChatRequest, gf_token: str = Depends(require_auth)):
             history_messages.append(AIMessage(content=content))
 
     initial_state: AgentState = {
-        "user_query": req.query,
+        "user_query": user_text,
         "messages": history_messages,
         "query_type": "",
         "portfolio_snapshot": {},
@@ -607,6 +632,7 @@ async def chat_steps(req: ChatRequest, gf_token: str = Depends(require_auth)):
     then a meta event with final metadata, then token events for the response.
     """
     start = time.time()
+    user_text = req.get_text()
 
     history_messages = []
     for m in req.history:
@@ -618,7 +644,7 @@ async def chat_steps(req: ChatRequest, gf_token: str = Depends(require_auth)):
             history_messages.append(AIMessage(content=content))
 
     initial_state: AgentState = {
-        "user_query": req.query,
+        "user_query": user_text,
         "messages": history_messages,
         "query_type": "",
         "portfolio_snapshot": {},
@@ -680,7 +706,7 @@ async def chat_steps(req: ChatRequest, gf_token: str = Depends(require_auth)):
 
                     cost_log.append({
                         "timestamp": datetime.utcnow().isoformat(),
-                        "query": req.query[:80],
+                        "query": user_text[:80],
                         "estimated_cost_usd": round(COST_PER_REQUEST_USD, 5),
                         "latency_seconds": elapsed,
                     })