fix(gui): separate fallback choices from the refreshed subagent roster

[lidge-jun]

Summary

A stale cached fallback availability list could hide new models from the main Subagents roster when the auxiliary fallback request failed. Keep roster availability separate and pass fallback availability only into the fallback editor.

Adds regression scenarios with cached [a], fresh roster [a,b], and either fallback 503 or independently successful fallback discovery. This is a pre-publication follow-up to #3927.

Verification

• Independent source re-review requested.
• Local tests, builds, typechecks and installs NOT RUN per owner instruction. Hosted CI is the verification gate.
• Only three files change; no credentials or routing behavior changes.

GUI layout is unchanged; prior mocked failure-path capture for the same workspace:

Checklist

• Scope stays focused and avoids unrelated cleanup.
• Docs or release notes were updated when needed; this restores the documented independent-loading contract.
• Security-sensitive changes were reviewed for secrets, auth, and unsafe defaults.

Maintainer integration: exact head 0d7652a passed Cross-platform CI34147331533 and prior independent source re-review. Remote macmini-cf used project Bun1.4.0,44 focused tests passed; no local tests/build/install/typecheck were run. The scope helper confirms current maintainer authority and no outstanding maintainer objection. Integrate through the owner-authorized release task; any subsequent automatic review findings will be checked before publication.

Summary by CodeRabbit

• Bug Fixes

  • Kept current roster availability separate from fallback model discovery, preventing stale fallback data from affecting fresh choices.
  • Fallback controls now remain disabled when model discovery is unavailable.
  • Saving fallback selections now commits only the models selected in the fallback picker.

• Tests

  • Added coverage for successful and failed model discovery scenarios to verify fallback selection behavior.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Team

Run ID: 2d132ddd-3ac4-48fd-9113-959fe1b70417

📥 Commits

Reviewing files that changed from the base of the PR and between 2abf071 and 0d7652a.

📒 Files selected for processing (3)

• gui/src/components/subagents-workspace/SubagentsWorkspace.tsx
• gui/src/pages/Subagents.tsx
• gui/tests/subagents-fallback.test.tsx

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📝 Walkthrough

Walkthrough

The change separates roster availability from fallback discovery availability. SubagentsWorkspace forwards the distinct lists to fallback controls, and tests cover discovery failures, successful filtering, saving, and cache fixtures.

Changes

Fallback availability separation

Layer / File(s)	Summary
Separate model availability wiring gui/src/components/subagents-workspace/SubagentsWorkspace.tsx, gui/src/pages/Subagents.tsx	At lines 35, 68, and 252, SubagentsWorkspace accepts fallbackAvailable and passes it to SubagentDelegationSection. At lines 323–324, Subagents.tsx passes roster available and fallback discovery results separately.
Fallback discovery and save coverage gui/tests/subagents-fallback.test.tsx	Lines 311–356 test 503 and 200 discovery responses. Lines 653–660 add fallbackAvailable to committed cache fixtures.

Estimated code review effort: 2 (Simple) | ~10 minutes

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/release-247-roster-fix

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[github-actions]

✅ Deterministic PR hygiene checks passed.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-07T17:36:42.830815Z	0d7652a	Draft marked ready

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