From e57adc0a6e9c1941b5e9c06a2e46e052103fc30f Mon Sep 17 00:00:00 2001
From: Charles Packer <packercharles@gmail.com>
Date: Mon, 5 Jan 2026 17:35:10 -0800
Subject: [PATCH] chore: mark agent.messages.stream endpoint as deprecated
 (#8227)

---
 fern/openapi.json                          | 3 ++-
 letta/server/rest_api/routers/v1/agents.py | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/fern/openapi.json b/fern/openapi.json
index 11f1d366..eb949869 100644
--- a/fern/openapi.json
+++ b/fern/openapi.json
@@ -7748,8 +7748,9 @@
       "post": {
         "tags": ["agents"],
         "summary": "Send Message Streaming",
-        "description": "Process a user message and return the agent's response.\nThis endpoint accepts a message from a user and processes it through the agent.\nIt will stream the steps of the response always, and stream the tokens if 'stream_tokens' is set to True.",
+        "description": "Process a user message and return the agent's response.\n\nDeprecated: Use the `POST /{agent_id}/messages` endpoint with `streaming=true` in the request body instead.\n\nThis endpoint accepts a message from a user and processes it through the agent.\nIt will stream the steps of the response always, and stream the tokens if 'stream_tokens' is set to True.",
         "operationId": "create_agent_message_stream",
+        "deprecated": true,
         "parameters": [
           {
             "name": "agent_id",
diff --git a/letta/server/rest_api/routers/v1/agents.py b/letta/server/rest_api/routers/v1/agents.py
index 2e60def3..3dbc7a4d 100644
--- a/letta/server/rest_api/routers/v1/agents.py
+++ b/letta/server/rest_api/routers/v1/agents.py
@@ -1625,6 +1625,7 @@ async def send_message(
             },
         }
     },
+    deprecated=True,
 )
 async def send_message_streaming(
     request_obj: Request,  # FastAPI Request
@@ -1635,6 +1636,9 @@ async def send_message_streaming(
 ) -> StreamingResponse | LettaResponse:
     """
     Process a user message and return the agent's response.
+
+    Deprecated: Use the `POST /{agent_id}/messages` endpoint with `streaming=true` in the request body instead.
+
     This endpoint accepts a message from a user and processes it through the agent.
     It will stream the steps of the response always, and stream the tokens if 'stream_tokens' is set to True.
     """