Model Routing

Purpose

How Hermes selects providers, applies combos, and enforces context limits.

Current Flow

• Main path: custom:litellm → http://litellm:4000/v1
• Default model: freellmapi-auto
• OmniRoute used for auxiliary roles: vision, skills_hub, approval, mcp, title_generation, web_extract, compression

Context Enforcement

• Three layers: model native → combo data.config.context_length → Hermes client cap
• Effective context is the minimum of the three

Combo Behavior

• priority retries same provider up to maxRetries, then errors; it does NOT fall through
• fill-first walks the list on failure
• auto/lkgp recalculates per request using health scoring
• Same-provider entries in a combo share rate-limit buckets
• Session affinity caches provider in session_model_history

Aliases and Mappings

• Model aliases resolved via key_value table (modelAliases namespace)
• Wildcard mappings via model_combo_mappings
• OpenCode/Zen entries may resolve back to opencode-zen provider internally

History

• User-provided: OpenRouter was used previously; provider lists now centered on LiteLLM + OmniRoute
• User-provided: persist_switch_by_default=false; /model is per-session unless --global used
• Inferred: Configuration undergoes periodic corrections related to vision, model fallback, and browser backend tuning

Related

• model-providers
• omniroute
• openrouter