[FEATURE]: Surface readable error messages when custom tool plugins fail to load

[joaomj]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Problem

When a custom tool plugin in ~/.config/opencode/tools/ fails to load (e.g. missing npm dependency, syntax error, or module resolution failure), opencode surfaces a generic "Unexpected server error. Check server logs for details." to the user with no indication of what went wrong.

The server log itself shows a raw ResolveMessage stack trace with no user-friendly explanation:

ResolveMessage: Cannot find module '@opencode-ai/plugin' from '/home/user/.config/opencode/tools/slack_lint.ts'

This requires the user to:

1. Know that server logs exist at ~/.local/share/opencode/log/opencode.log
2. Dig through thousands of log lines
3. Parse a raw Bun module resolution error to understand the problem

Proposed solution

Surface tool-load failures as readable messages in the UI/CLI instead of the opaque "Unexpected server error". At minimum, log the error in a way that clearly states what failed and how to fix it — for example:

Failed to load tool slack_lint: missing dependency @opencode-ai/plugin. Run npm install in your config directory.

This would save users significant debugging time and make custom tool development much more approachable.

[github-actions]

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

• Server plugins that fail to load are silently dropped (no stderr output) #34742: Server plugins that fail to load are silently dropped (no stderr output) — same core problem of silent plugin load failures
• Loading local plugin silently fails in case of an error #21638: Loading local plugin silently fails in case of an error — same problem with local plugins failing without user-visible errors
• plugin dependency failure causes silent prompt_async crash with ERR_MODULE_NOT_FOUND, no error shown in UI #28286: Plugin dependency failure causes silent crash with ERR_MODULE_NOT_FOUND, no error shown in UI — same root cause (missing module, no readable error surfaced)
• error: Cannot find module '@opencode-ai/plugin' from #5860: Reports the exact same Cannot find module '@opencode-ai/plugin' error with no user-friendly message
• OpenCode silently enters a broken UI state when a plugin fails to initialize #24847: OpenCode silently enters a broken UI state when a plugin fails to initialize — related UX gap

If your issue is distinct from all of the above, please clarify what's different so maintainers can triage it separately.

[joaomj]

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

• Server plugins that fail to load are silently dropped (no stderr output) #34742: Server plugins that fail to load are silently dropped (no stderr output) — same core problem of silent plugin load failures
• Loading local plugin silently fails in case of an error #21638: Loading local plugin silently fails in case of an error — same problem with local plugins failing without user-visible errors
• plugin dependency failure causes silent prompt_async crash with ERR_MODULE_NOT_FOUND, no error shown in UI #28286: Plugin dependency failure causes silent crash with ERR_MODULE_NOT_FOUND, no error shown in UI — same root cause (missing module, no readable error surfaced)
• error: Cannot find module '@opencode-ai/plugin' from #5860: Reports the exact same Cannot find module '@opencode-ai/plugin' error with no user-friendly message
• OpenCode silently enters a broken UI state when a plugin fails to initialize #24847: OpenCode silently enters a broken UI state when a plugin fails to initialize — related UX gap

If your issue is distinct from all of the above, please clarify what's different so maintainers can triage it separately.

In my case i am just asking for improvements on the error messages in TUI.

[github-actions]

To stay organized issues are automatically closed after 60 days of no activity. If the issue is still relevant please open a new one.