Configurable model routing rules for Orchestrator subagent delegation

[dkritarth]

Context & Idea

With Orchestrator V2 and multi-provider support, users frequently want to leverage the distinct strengths, speeds, and cost profiles of different models within a single orchestrated workflow.

For example, in a complex research/engineering workflow:

• Gemini 3.8 Flash for high-throughput literature review, arXiv paper research, and web searches.
• GPT-6 Luna (High reasoning) for monitoring long-running remote cluster jobs (e.g., HPCC / SLURM) and reporting back upon completion.
• Claude Opus 5.5 for overarching project direction, architecture planning, and critical reviews.
• GPT-6.1 for focused, repetitive implementation and boilerplate grunt work.

Current Pain Point

Right now, to achieve this, we have to specifically and manually mention these routing instructions in every thread/prompt (or via repository instructions like .t3/instructions.md) to steer the orchestrator when it calls delegate_task. Having a way to configure these model-routing descriptions or rules directly in T3 Code settings—so the orchestrator naturally and automatically dispatches to the preferred model for a given type of task—would be a big relief and quality-of-life improvement.

It's not urgent, but as Orchestrator V2 matures, having configurable orchestrator delegation policies could be a great direction for multi-agent workflows.

Potential Architecture

1. Settings / Config: Add an optional orchestratorRoutingRules array in settings.json specifying:
   • User description / task intent (e.g., "literature review, search papers")
   • Optional role ("research" | "implementation" | "review" | ...)
   • Target provider instance, model ID, and options (e.g., { providerInstanceId: "antigravity", model: "gemini-3.8-flash-high" }).
2. Instruction Injection: Dynamic injection of the user's routing guidelines into the system instructions in T3OrchestrationInstructions.ts.
3. Server-side Resolution: Fallback in OrchestratorMcpService.ts to match role or task description to the configured routing rules if no explicit model target is provided in delegate_task.
4. Settings UI: A simple management panel in Settings to add, reorder, or edit rules with provider and model pickers.

Opening this discussion to gather thoughts and feedback from the community and maintainers!

[pekth]

This can be done locally with your markdown files for agents to read. There is no need to hard-coded.

[andrelima-arch]

It would be really useful to have this configurable directly through the UI.

Cursor already has something similar, where you can select which subagent to use, and it will automatically be used whenever needed.

T3 Code could implement a similar approach, allowing users to select a specific agent or model as the default for subagent tasks. Whenever the orchestrator needs to delegate a task, it would automatically use the previously selected agent without requiring manual instructions in every prompt.