> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tamarind.bio/llms.txt
> Use this file to discover all available pages before exploring further.

# Model router

> Recommend the best structure-prediction tool from FoldBench benchmark evidence

The model router recommends which structure-prediction tool to run, ranked by Tamarind's FoldBench benchmark rather than by keyword match. There is no separate button or dashboard for it.

Use it in two places:

* **Assistant chat** — ask what to run for a structure task (antibody–antigen, protein–ligand, protein–protein). That call *is* the model router.
* **API** — `POST https://app.tamarind.bio/api/model-router` with your API key.

Do not call `model-router.tamarind.bio` yourself. That host is internal.

If the feature is not enabled for your account, the chat tool is hidden and the API returns 403. Email [info@tamarind.bio](mailto:info@tamarind.bio) if you need it turned on.

## In chat

Open [Assistant](https://app.tamarind.bio/assistant) and describe the prediction, for example:

> What's the best tool for this antibody–antigen complex? PDB 9PY6.

The assistant calls the model router (`recommendModel`) and relays the ranked list. Asking "how do I access the model router" is the same feature — you already have it in that chat when the tool is available.

Name a PDB accession in the question when you have one, rather than pasting its chains. Pass sequences and roles only when you already have the residues.

A recommendation takes about 15 to 25 seconds.

## From the API

`POST https://app.tamarind.bio/api/model-router`

Authenticate with `x-api-key`. Get a key from [API docs](https://app.tamarind.bio/api-docs/api-key). Give the client a generous timeout — a call takes about 15 to 25 seconds.

```bash theme={null}
curl -X POST https://app.tamarind.bio/api/model-router \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"prompt": "predict the structure of this antibody-antigen complex"}'
```

The body is `{ "prompt": "...", "inputs": [...] }`. `prompt` is required. `inputs` is optional: sequences or ligands you already have, each with exactly one of `sequence`, `smiles`, or `ccd`, plus an optional `role` (`heavy`, `light`, `antigen`, `target`, `enzyme`).

A sequence pasted into `prompt` is found and used as well. Sending them under `inputs` is better when you can label roles.

Full request and response fields: [API docs → Model Router](https://app.tamarind.bio/api-docs).

## How to read the answer

A 200 is a normal answer even when nothing is recommended.

* `tools` is ranked, best first. Run the first one. The list is usually two to four tools — not the whole catalog.
* Each row has a `toolId` and a `reason` that quotes the benchmark claim when one exists.
* `abstain: true` with an empty `tools` list means no tool could be justified. `summary` says what was missing. Say more and call again.
* `403` means recommendations are not enabled for this account.

## Related

* [API](/tamarind/api) — REST overview
* [Structure Prediction](/tasks/structure-prediction) — task-level tool notes
* [API docs](https://app.tamarind.bio/api-docs) — Model Router reference