Feature Request: Add --auto_create_session flag to adk api_server CLI

Summary

ADK v1.23.0 added support for automatic session creation via the auto_create_session parameter in the Runner class (commit 8e69a58). However, this feature is not exposed in the adk api_server CLI, requiring frontend applications to manually create sessions before calling /run.

Current Behavior

The _create_runner method in adk_web_server.py creates the Runner without the auto_create_session parameter:

def _create_runner(self, agentic_app: App) -> Runner:
    return Runner(
        app=agentic_app,
        artifact_service=self.artifact_service,
        session_service=self.session_service,
        memory_service=self.memory_service,
        credential_service=self.credential_service,
        # auto_create_session is not passed, defaults to False
    )

This means /run returns 404 Session not found if the session doesn't exist, even though the Runner has the capability to auto-create it.

Proposed Solution

Add a --auto_create_session flag to adk api_server:

adk api_server --auto_create_session --allow_origins="https://example.com" .

This would pass auto_create_session=True to the Runner, enabling the feature that already exists in the codebase.

Use Case

Frontend applications (especially those running in restricted environments like Looker Extensions) would benefit from simplified session management. Currently, we need to:

GET /sessions/{id} to check if session exists
POST /sessions/{id} to create if not found
POST /run to send the message

With --auto_create_session, step 1 and 2 become unnecessary, reducing latency and code complexity.

Alternatives Considered

Manual session creation in frontend - Current workaround, adds complexity
Custom FastAPI server - Requires maintaining a fork
Environment variable - Could also work (e.g., ADK_AUTO_CREATE_SESSION=1)

Additional Context

ADK Version: 1.23.0
The auto_create_session feature works correctly when using the Runner directly in Python scripts
This is specifically about exposing the existing feature via the CLI

Also need in get_fast_api_app.

@sasha-gitg

Hii @sasha-gitg I’m new to this repository and recently started contributing to open source. I saw the labeled as “good first issue” and “help wanted,” and I would love to work on it. Could you please guide me on how to get started?

@sasha-gitg

Hello @sasha-gitg, I am also new to open source contributions and would like to work on this feature. I can start tonight if assigned to me.

feat(cli): Add `--auto_create_session` flag to `adk api_server` CLI

@Subhrasameerdash

@Subhrasameerdash @Zmer03 This one is already solved, feel free to look for other issues, and the CONTRIBUTING.md file is a good start.

@wuliang229

Sure @wuliang229 I ll check it out

@wuliang229

@wuliang229 @sasha-gitg @ekimcodes The fix you merged (#4288) was incomplete and does not work.

Please apply the following diff so the /run and /run_sse endpoints respect the auto_create_session flag:

diff --git a/src/google/adk/cli/adk_web_server.py b/src/google/adk/cli/adk_web_server.py
index c61f855f..014d21ff 100644
--- a/src/google/adk/cli/adk_web_server.py
+++ b/src/google/adk/cli/adk_web_server.py
@@ -1558,11 +1558,12 @@ class AdkWebServer:
 
     @app.post("/run", response_model_exclude_none=True)
     async def run_agent(req: RunAgentRequest) -> list[Event]:
-      session = await self.session_service.get_session(
-          app_name=req.app_name, user_id=req.user_id, session_id=req.session_id
-      )
-      if not session:
-        raise HTTPException(status_code=404, detail="Session not found")
+      if not self.auto_create_session:
+        session = await self.session_service.get_session(
+            app_name=req.app_name, user_id=req.user_id, session_id=req.session_id
+        )
+        if not session:
+          raise HTTPException(status_code=404, detail="Session not found")
       runner = await self.get_runner_async(req.app_name)
       async with Aclosing(
           runner.run_async(
@@ -1581,11 +1582,12 @@ class AdkWebServer:
     @app.post("/run_sse")
     async def run_agent_sse(req: RunAgentRequest) -> StreamingResponse:
       # SSE endpoint
-      session = await self.session_service.get_session(
-          app_name=req.app_name, user_id=req.user_id, session_id=req.session_id
-      )
-      if not session:
-        raise HTTPException(status_code=404, detail="Session not found")
+      if not self.auto_create_session:
+        session = await self.session_service.get_session(
+            app_name=req.app_name, user_id=req.user_id, session_id=req.session_id
+        )
+        if not session:
+          raise HTTPException(status_code=404, detail="Session not found")
 
       # Convert the events to properly formatted SSE
       async def event_generator():

feat(cli): Add `--auto_create_session` flag to `adk api_server` CLI

We have a fix incoming.

feat(cli): Add `--auto_create_session` flag to `adk api_server` CLI

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Feature Request: Add --auto_create_session flag to adk api_server CLI #4274

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Feature Request: Add --auto_create_session flag to adk api_server CLI #4274

Description

Summary

Current Behavior

Proposed Solution

Use Case

Alternatives Considered

Additional Context

Activity

hymanme commented on Jan 27, 2026

Subhrasameerdash commented on Jan 28, 2026

Zmer03 commented on Feb 2, 2026

wuliang229 commented on Feb 11, 2026

Subhrasameerdash commented on Feb 12, 2026

mynewestgitaccount commented on Feb 21, 2026

sasha-gitg commented on Feb 23, 2026

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