Implement full fallback_models support across all integration points:
1. Model Resolution Pipeline (src/shared/model-resolution-pipeline.ts)
- Add userFallbackModels to ModelResolutionRequest
- Process user fallback_models before hardcoded fallback chain
- Support both connected provider and availability checking modes
2. Agent Utils (src/agents/utils.ts)
- Update applyModelResolution to accept userFallbackModels
- Inject fallback_models for all builtin agents (sisyphus, oracle, etc.)
- Support both single string and array formats
3. Model Resolver (src/shared/model-resolver.ts)
- Add userFallbackModels to ExtendedModelResolutionInput type
- Pass through to resolveModelPipeline
4. Delegate Task Executor (src/tools/delegate-task/executor.ts)
- Extract category fallback_models configuration
- Pass to model resolution pipeline
- Register session category for runtime-fallback hook
5. Session Category Registry (src/shared/session-category-registry.ts)
- New module: maps sessionID -> category
- Used by runtime-fallback to lookup category fallback_models
- Auto-cleanup support
6. Runtime Fallback Hook (src/hooks/runtime-fallback/index.ts)
- Check SessionCategoryRegistry first for category fallback_models
- Fallback to agent-level configuration
- Import and use SessionCategoryRegistry
Test Results:
- runtime-fallback: 24/24 tests passing
- model-resolver: 46/46 tests passing
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
- Add Category-level fallback_models support in getFallbackModelsForSession()
- Try agent-level fallback_models first
- Then try agent's category fallback_models
- Support all builtin agents including hephaestus, sisyphus-junior, build, plan
- Expand agent name recognition regex to include:
- hephaestus, sisyphus-junior, build, plan, multimodal-looker
- Add comprehensive test coverage (6 new tests, total 24):
- Model switching via chat.message hook
- Agent-level fallback_models configuration
- SessionID agent pattern detection
- Cooldown mechanism validation
- Max attempts limit enforcement
All 24 tests passing
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Add configuration schemas for runtime model fallback feature:
- RuntimeFallbackConfigSchema with enabled, retry_on_errors,
max_fallback_attempts, cooldown_seconds, notify_on_fallback
- FallbackModelsSchema for init-time fallback model selection
- Add fallback_models to AgentOverrideConfigSchema and CategoryConfigSchema
- Export types and schemas from config/index.ts
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
youming.tang