real dev verification: pingdotgg/t3code #23957
main: 32ecd71726 (github/main; separate /home/user/main worktree)
pr: b4547bd775674aaaea6e3635ced00f37bf8c544d (exact contributor head)

setup: vp i; one background vp run dev at a time; Playwright + /usr/bin/google-chrome.
project and git repository created with Add project > New project.
Codex fallback instance added through Settings > Providers.
new-thread default: codex, gpt-6.1-sol, reasoningEffort=xhigh.
primary disabled through Settings. gpt-6.1-sol registered as a custom model on disabled primary because disabling clears its discovered catalog.
no mocks, fixtures, demo data, or source modifications.

client WebSocket launchThread selections:
{"text":"Reply with exactly FALLBACK_OK. Do not use tools or change files.","modelSelection":{"instanceId":"codex_fallback","model":"gpt-6.1-sol"}}
{"text":"Reply with exactly FALLBACK_OK. Do not use tools or change files.","modelSelection":{"instanceId":"codex_fallback","model":"gpt-6.1-sol","options":[{"id":"reasoningEffort","value":"xhigh"},{"id":"serviceTier","value":"default"}]}}
{"text":"Reply with exactly OWN_OPTIONS_OK. Do not use tools or change files.","modelSelection":{"instanceId":"codex_fallback","model":"gpt-6.1-sol","options":[{"id":"reasoningEffort","value":"high"},{"id":"serviceTier","value":"default"}]}}

main: real Codex app-server protocol (selected fields only):
{"direction":"outgoing","method":"turn/start","model":"gpt-6.1-sol","effort":"OMITTED","serviceTier":"OMITTED","prompt":"Reply with exactly FALLBACK_OK. Do not use tools or change files."}
{"direction":"incoming","method":"item/completed","text":"FALLBACK_OK"}
{"direction":"incoming","method":"turn/completed","status":"completed"}

pr: real Codex app-server protocol (selected fields only):
{"direction":"outgoing","method":"turn/start","model":"gpt-6.1-sol","effort":"xhigh","serviceTier":"default","prompt":"Reply with exactly FALLBACK_OK. Do not use tools or change files."}
{"direction":"incoming","method":"item/completed","text":"FALLBACK_OK"}
{"direction":"incoming","method":"turn/completed","status":"completed"}
{"direction":"outgoing","method":"turn/start","model":"gpt-6.1-sol","effort":"high","serviceTier":"default","prompt":"Reply with exactly FOLLOWUP_OK. Do not use tools or change files."}
{"direction":"incoming","method":"item/completed","text":"FOLLOWUP_OK"}
{"direction":"incoming","method":"turn/completed","status":"completed"}
{"direction":"outgoing","method":"turn/start","model":"gpt-6.1-sol","effort":"high","serviceTier":"default","prompt":"Reply with exactly OWN_OPTIONS_OK. Do not use tools or change files."}
{"direction":"incoming","method":"item/completed","text":"OWN_OPTIONS_OK"}
{"direction":"incoming","method":"turn/completed","status":"completed"}

UI assertions on PR:
- fallback picker selected Codex fallback; GPT-6.1-Sol; Extra High checked.
- FALLBACK_OK visible and turn completed.
- explicit High followup returned FOLLOWUP_OK; both messages and High survived reload.
- draft held codex=xhigh and codex_fallback=high; disable codex; High won; returned OWN_OPTIONS_OK.

blacksmith check: vp test run apps/web/src/modelSelection.test.ts apps/web/src/composerDraftStore.test.ts apps/web/src/components/ChatView.logic.test.ts
result: 3 files passed; 145 tests passed.
head CI: 26 success, 0 failing, 0 pending.
not verified: native desktop/mobile, remote/relay/tunnel, real non-Codex providers, cross-driver live fallback. Existing focused tests cover different-model and cross-driver option rejection.