Model router

[shatfield4]

Pull Request Type

• ✨ feat (New feature)
• 🐛 fix (Bug fix)
• ♻️ refactor (Code refactoring without changing behavior)
• 💄 style (UI style changes)
• 🔨 chore (Build, CI, maintenance)
• 📝 docs (Documentation updates)

Relevant Issues

resolves #5313
Translations PR: #5390

Description

• Add model router as a new provider type that routes messages to different LLM providers/models based on configurable rules
• Support two rule types: calculated (deterministic conditions) and LLM-classified (semantic matching via fallback model)
• Route based on prompt content, conversation token count, message count, time of day, or image attachments
• CSV support for keyword matching ("python,javascript,coding" matches any)
• Configurable cooldown to cache routing decisions and avoid reevaluation on every message (decided to keep this so that users can dial it in to work for their specific workflows)
• Full settings UI for creating/editing routers and rules with drag-and-drop priority ordering
• Inline provider credential setup when configuring routing targets
• Works in both regular chat and agent mode, including per-turn re-routing in agent mode
• Ephemeral routing notification shown in chat during streaming with animated border, disappears on refresh
• Router selectable at system level or per-workspace via the model picker

Visuals (if applicable)

Model routing animation

model.routing.animation.mov

Chat UI with model router switching to different models

Agent mode chat UI with router switching to different models

Model router settings page

Editing router

Router rules configuration

Additional Information

Developer Validations

• I ran yarn lint from the root of the repo & committed changes
• Relevant documentation has been updated (if applicable)
• I have tested my code functionality
• Docker build succeeds locally