TUI shows server error on `--continue --fork`: Expected a string starting with "ses", got "dummy"

[suderman]

Description

When starting OpenCode with opencode --continue --fork, the fork opens and appears usable, but the TUI shows this toast on startup:

Unexpected server error. Check server logs for details.

The server log shows a request failing because the session id is "dummy" instead of a real ses_... id:

ERROR service=server ref=err_edf4a03a error=Expected a string starting with "ses", got "dummy"

This has happened repeatedly when forking sessions after a previous session became stuck/queued. I can continue working in the fork, so the error is not fatal, but it looks like the TUI/server is making a startup request with a placeholder session id before the real forked session id is available.

I am using this as a workaround for sessions that appear wedged: the original session stops processing new messages / leaves them queued, but --continue --fork lets me continue.

Plugins

"opencode-ntfy.sh", "opencode-minimax-easy-vision", "@simonwjackson/opencode-direnv", "@tarquinen/opencode-dcp@latest"

OpenCode version

1.15.10

Steps to reproduce

1. Have an existing OpenCode session that previously stalled or stopped processing queued messages.
2. Start a fork from the CLI:

opencode --continue --fork

3. Observe that the forked session opens and can still be used.

4. Observe the TUI toast:

Unexpected server error. Check server logs for details.

5. Check the OpenCode logs:

rg -n -C 10 'Expected a string starting with "ses", got "dummy"' ~/.local/share/opencode/log

6. Logs show:

ERROR service=server ref=err_edf4a03a error=Expected a string starting with "ses", got "dummy"

Screenshot and/or share link

Screenshot attached showing the TUI toast:

Unexpected server error. Check server logs for details.

Relevant log excerpt:

/home/jon/.local/share/opencode/log/2026-05-25T191925.log:59:
INFO service=session id=ses_19f6c1805ffe2ziZ0G3WZCdgAW slug=jolly-cabin version=1.15.10 ...

/home/jon/.local/share/opencode/log/2026-05-25T191925.log:112:
ERROR service=server ref=err_edf4a03a error=Expected a string starting with "ses", got "dummy"

I also see MCP -32601 Method not found errors for resources/prompts around startup, but those look unrelated/noisy because the visible toast appears to correspond to the "dummy" session id server error.

Operating System

NixOS 25.11

Terminal

Kitty

[github-actions]

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

• Historical sessions disappear - Expected a string starting with "ses", got "dummy" error #28486: Same Expected a string starting with "ses", got "dummy" error — reported in the context of historical sessions disappearing, but the underlying cause may overlap with the placeholder session ID used during --continue --fork startup.

[Arjith8]

I have seen this happen when using -c/--continue on a folder/git proj where u never started opencode from before in this case we use session id as dummy which was ok till at some point the team added validation to session ID and that validation raises this server error upon failure, I did feel the error resp was misleading so I had created a PR for the error to be updated a bit back #27776

[suderman]

Hmm. The motivation behind this issue is me chasing a recent bug where opencode just stalls out. Prompts get queued up, nothing more gets sent out. Sessions of any size, really.

My workaround is to kill the process and restart with opencode --continue --fork and then I can keep going forward in my session.

It's really frustrating, but it was worse before I figured out the workaround.

[Arjith8]

Kill the process? as in /exit or similar?? If u kill the process as a whole not sure if all data will be gracefully

[suderman]

I mean ctrl-c. Exit the tui.