ModelRefs / Multi-Tool Router — Agent Pattern
Multi-Tool Router — Agent Pattern
Route between a curated catalog of tools using either model selection or a deterministic classifier.
Overview
Expose N tools to the model and let it select which to call per step. For large catalogs, prepend a lightweight tool-router (classifier or retrieval) to prune the catalog before each step.
When to use it: Your agent needs more than one capability but the catalog stays under ~15 tools.
Pattern details
| Pattern class | tool-use |
|---|---|
| Difficulty | intermediate |
| Autonomy | guided |
| Also known as | tool router, tool selector |
| Last reviewed | 2026-06-07 |
Known failure modes
- Tool confusion — Model picks the wrong tool past ~15 tools. Mitigation: Add a tool router or split into sub-agents.
- Schema violation — Arguments fail validation. Mitigation: Return validation error to the model and let it retry.
When not to use it
- Stuffing 50+ tools into one prompt every turn.
Continue your research
Use these connected ModelRefs sections to compare alternatives, inspect implementation paths, and review the evidence and governance boundaries relevant to Multi-Tool Router — Agent Pattern.
Frequently asked questions
When should I use the Multi-Tool Router agent pattern?
Your agent needs more than one capability but the catalog stays under ~15 tools.
What are common failure modes of Multi-Tool Router?
Tool confusion • Schema violation
Is Multi-Tool Router production-ready?
Yes when paired with the safety controls and observability hooks documented on the pattern page.