Desktop app crashes in session UI with TypeError reading undefined.id after enabling opencode-pty

[FldBudin]

Description

While running work in parallel agents in OpenCode Desktop, one of the spawned agent branches encountered an image attachment/reference in the inherited task context and failed with:

ERROR: Cannot read "image.png" (this model does not support image input). Inform the user.

Immediately after that, the desktop app crashed in the session UI with the following frontend error:

TypeError: Cannot read properties of undefined (reading 'id')
    at Object.fn (http://tauri.localhost/assets/session-Cz3nr7GB.js:16:91816)
    at runComputation (http://tauri.localhost/assets/index-C02PVil6.js:1:6735)
    at updateComputation (http://tauri.localhost/assets/index-C02PVil6.js:1:6483)
    at runTop (http://tauri.localhost/assets/index-C02PVil6.js:1:7917)
    at runQueue (http://tauri.localhost/assets/index-C02PVil6.js:1:8818)
    at completeUpdates (http://tauri.localhost/assets/index-C02PVil6.js:1:8191)
    at runUpdates (http://tauri.localhost/assets/index-C02PVil6.js:1:8108)
    at batch (http://tauri.localhost/assets/index-C02PVil6.js:1:3650)
    at flush (http://tauri.localhost/assets/index-BSjWd8pK.js:2322:44912)

This suggests the desktop frontend does not gracefully handle a parallel-agent task failure caused by unsupported image input, and some session-page derived state later becomes invalid/undefined during recomputation.

I reviewed the current dev source locally and this still looks like a frontend packages/app session-page state issue rather than a backend PTY/command execution failure. I have not source-mapped the exact bundle offset yet, so the items below are suspected source regions rather than a confirmed root cause:

• packages/app/src/components/session/session-header.tsx
• packages/app/src/pages/session/terminal-panel.tsx
• packages/app/src/context/terminal.tsx

Most suspicious direct accesses found in review:

• packages/app/src/components/session/session-header.tsx:333
• packages/app/src/components/session/session-header.tsx:368

Plugins

opencode-pty@latest

OpenCode version

1.2.27

Steps to reproduce

I do not have a minimal deterministic repro yet, but the crash happened in this sequence:

1. Run work that spawns parallel agents/tasks in OpenCode Desktop.

2. One spawned branch inherits or encounters an image input/reference (image.png) from the active conversation/task context.

3. That branch uses a model that does not support image input and reports:

   ERROR: Cannot read "image.png" (this model does not support image input). Inform the user.
   

4. After that branch fails, the desktop session UI crashes with the Cannot read properties of undefined (reading 'id') frontend error above.

Additional context:

• opencode-pty@latest was enabled in the environment, but I do not have evidence that it is the root cause.
• The more accurate trigger I observed is: parallel agent work + inherited image input + model without image support + subsequent desktop UI crash.

Screenshot and/or share link

No screenshot/share link available. I captured the error text directly.

Operating System

Windows 11 (NT 10.0.26100.0)

Terminal

OpenCode Desktop (Tauri)

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• The actual error message/stack trace is missing — the description says "the following frontend error:" but no error text is included
• The bullet lists for "high-suspicion areas" and "Most suspicious direct accesses" are empty
• The Plugins field is blank (please list which plugins were active, specifically opencode-pty)
• The OpenCode version field is empty — please include your exact version

Please edit this issue to address the above within 2 hours, or it will be automatically closed.

---

This issue might be a duplicate of existing issues. Please check:

• Switching conversations and then sending a message causes it to crash—this happens frequently. #17759: Desktop app crashes in session UI with a SolidJS TypeError on Windows 11 — very similar symptoms (session-page state crash after switching sessions)
• Desktop: Session spinners persist indefinitely due to SolidJS store merge behavior in bootstrap #17657: Desktop session spinners persist due to SolidJS store merge behavior — related session/store state root cause

If you believe this was flagged incorrectly, please let a maintainer know.

[github-actions]

Thanks for updating the issue! It now includes all the required information — a description with a real stack trace, steps to reproduce, version, OS, and terminal details. Everything looks good.

[FldBudin]

Additional repro-oriented context from the session where this happened:

I had OpenCode Desktop running with opencode-pty@latest enabled, and I asked the main agent to do parallel research work by spawning multiple sub-agents/tasks at once.

The parallel branches were doing things like:

• searching GitHub / the web for interactive-terminal-related skills
• comparing term-cli vs interminai
• checking Windows compatibility and OpenCode fit

So this was not a single serial task; it was a fan-out / parallel-agent workflow from one active desktop session.

The important part is that these spawned branches appear to inherit or otherwise encounter artifacts from the parent conversation/task context. In this run, one branch hit:

ERROR: Cannot read "image.png" (this model does not support image input). Inform the user.

My current best guess for reproduction is:

1. Start from an OpenCode Desktop session that already has some richer context/history attached.
2. Ask the main agent to spawn multiple parallel research/analysis tasks.
3. At least one spawned branch ends up with an image attachment/reference (image.png) in its effective context.
4. That branch runs on a model that does not support image input.
5. The branch throws the unsupported-image error.
6. Shortly after, the desktop session UI crashes with the undefined.id frontend error.

I still cannot prove whether the image reference is explicitly attached, inherited from the parent thread, or reconstructed from session state/history. But the strongest observable sequence was:

parallel agents -> one branch gets image.png -> model rejects image input -> desktop session UI crashes.