[AndrianBalanescu]

Problem

When a user requests a non-existent Antigravity model (e.g. gemini-3.6), the upstream returns 404 and OmniRoute locks the entire Gemini family (family:gemini) on that connection. All sibling models (gemini-3.1-flash-lite, gemini-1.5-flash, etc.) become unavailable with model_cooldown until the lockout expires — even though only the requested model doesn't exist.

Root Cause

getModelLockKey() in open-sse/services/accountFallback.ts always maps Antigravity Gemini models to family:gemini for lockout keying — regardless of the error type. A 404 (Model Not Found) is model-specific, not family-wide, but it was being treated the same as a 429 (quota exhausted).

Fix

404 / not_found lockouts now scope to the exact model only (e.g. gemini-3.6), not the family key. Sibling models remain available.

429 / rate limit lockouts continue to lock the entire family (family:gemini) — correct, since Antigravity enforces quota per family.

Changes to accountFallback.ts

• getModelLockKey(): accepts optional reason / status; skips family resolution when reason === "not_found" or status === 404
• isModelLocked(): checks both exact key AND family key (so a model locked by exact 404 is still detected)
• getModelLockoutInfo(): returns exact entry if present, falls back to family entry
• clearModelLock(): clears both exact and family keys
• lockModel() / recordModelLockoutFailure(): pass reason / status through to getModelLockKey()

Also included: bare-model auto-pick

• Adds agy/ as a short alias for the Antigravity provider
• resolveModelByProviderInference now deduplicates alias providers and filters by active connections, auto-picking when only one active provider matches

Tests

• repro-antigravity-404-family-cooldown-hijack.test.ts: verifies 404 locks exact model only, 429 locks whole family
• bare-model-autopick.test.ts: verifies auto-pick resolves to antigravity for known models, falls back to ambiguous_model for genuinely ambiguous ones
• All existing lockout tests pass (31/31)

[gemini-code-assist]

Caution

The consumer version of Gemini Code Assist on GitHub has been sunset. All code review activity has officially ceased.

[diegosouzapw]

Obrigado, @AndrianBalanescu — mergeado na release/v3.8.49. Reconstruí cirurgicamente mantendo só a parte de model-lockout exact-vs-family (accountFallback.ts + model.ts + 2 testes) e dropando a metade de thinking-signature-recovery — o #7899 já estava corrigido e mergeado na release via #7906, então essa parte era redundante. Ajustei um type (resolveProviderAlias agora retorna string|null na release atual). 4/4 testes verdes.