[BUG] 0.9.7 UI: new chat hangs on "Thinking…"

[Gentoli]

📋 Prerequisites

• I have searched the existing issues to avoid creating a duplicate
• By submitting this issue, you agree to follow our Code of Conduct
• I am using the latest version of the software
• I have tried to clear cache/cookies or used incognito mode (if ui-related)
• I can consistently reproduce this issue

🎯 Affected Service(s)

UI Service

🚦 Impact/Severity

Blocker

🐛 Bug Description

Creating a new chat in UI 0.9.7 hangs indefinitely on "Thinking…". The session is created successfully, but the agent is never contacted — no POST /a2a/... request is issued. Reverting only the UI to 0.9.6 (backend unchanged) fixes it.

🔄 Steps To Reproduce

1. Deploy/upgrade to 0.9.7
2. Start new chat via UI

🤔 Expected Behavior

Able to create chat via UI

📱 Actual Behavior

UI shows "Thinking…" and never returns

Cancelling and sending a new message will work, but the first message will be gone on reload.

The UI makes the following requests:

POST /chat          -> POST /api/sessions                     201   (session created)
POST /chat/<uuid>   -> GET  /api/sessions/<ns>/<agent> 200   (sidebar refresh)
GET  /chat/<uuid>                                                   (RSC navigation)
GET  /chat/<uuid>                                                   (RSC navigation)
... stops; stuck on "Thinking…"

💻 Environment

• Browser: Firefox, Edge latest
• Version: 0.9.7
• v1.35.3-gke.2190000

🔧 CLI Bug Report

No response

🔍 Additional Context

Workaround - downgrade only UI to 0.9.6

no error logs in browser console, only access logs in kagent-ui pods. No sandboxed agents

📋 Logs

📷 Screenshots

No response

🙋 Are you willing to contribute?

• I am willing to submit a PR to fix this issue