Context

PR #3724 (merged as eba94215f075f1586b65045356233951eb89750b) added machinery to pkg/tui to hide no-op slash commands such as /settings in lean mode. On review, the change appears to target a code path that is no longer user-facing, and it introduces a latent correctness risk.

Problems

1. Wrong code path. The live --lean flow branches in cmd/root/run.go into runLeanTUI, which uses the separate pkg/leantui frontend. It does not construct pkg/tui with tui.WithLeanMode(). pkg/leantui also already omits /settings from its built-in command list, so the PR does not fix the currently active docker agent run --lean experience it claims to address.

2. Correctness risk / command-name collision. Filtering is done globally on slash-command text. An agent-defined custom command named settings (which produces an AgentCommandMsg and is not a no-op) would also be removed.

3. Test gap. The added tests instantiate the legacy pkg/tui model directly and do not exercise CLI routing or the real pkg/leantui command list.

4. Disproportionate complexity. Reflection and parallel registries add substantial machinery to exclude a single command on an apparently inactive path.

Suggested follow-up

Either:

• Revert the unnecessary pkg/tui lean-mode machinery introduced in fix(tui): hide no-op slash commands (/settings) in lean mode #3724, or
• First establish a real caller / reproduction for tui.WithLeanMode, and add coverage ensuring custom command-name collisions (e.g. a custom /settings) remain functional.

References

• Follows fix(tui): hide no-op slash commands (/settings) in lean mode #3724
• Related: fix(tui): match slash command value, not just label, in inline completion #3723