# Serve your own adapter

> Load a LoRA adapter you trained on the base, give it its own temperatures, check that the server serves it, and know what it does to certificates.

Source: https://opendecisio.com/docs/deploy/adapter/

Serve a LoRA adapter you trained on the base, and ask each [question](https://opendecisio.com/docs/glossary/#question) with it or without it. An adapter changes the scale of the model’s readout, so it carries its own temperatures: one per question type, and for choice questions one per band of [option](https://opendecisio.com/docs/glossary/#option) count. This writes decisio’s example file and has decisio check it, on any machine:

 

```
cat > decisio_adapter.json <<'EOF'
{"schema": "decisio.adapter/1",
 "temperatures": {"choice": 2.141, "noul": 3.075, "score": 4.185},
 "choice_bands": {"2-10": 1.9, "11-26": 2.6, "27-255": 3.1}}
EOF
uv run python -m decisio.serve.adapter_temperatures check decisio_adapter.json
```

 

Run against the CPU stand-in at v0.18.1 on 2026-10-19. It printed:

```
{
 "temperatures": {
  "choice": 2.141,
  "noul": 3.075,
  "score": 4.185
 },
 "choice_bands": {
  "2-10": 1.9,
  "11-26": 2.6,
  "27-255": 3.1
 },
 "fit": null,
 "file": "decisio_adapter.json"
}
```

 

## 1 Load the adapter

 

Start the server with `--adapter name=path`, once per adapter, and the adapter’s temperature file:

 

```
pip install "decisio[serve]==0.18.1"
python -m decisio.serve.vllm_engine --adapter my-adapter=/models/my-adapter \
  --adapter-temperatures my-adapter=decisio_adapter.json
```

 

Shown, not run: it needs Linux with one NVIDIA card and a LoRA adapter, which this check does not have.

 

- The adapter is a vLLM-format LoRA adapter, served unmerged, on the text route, in separate mode.
- A Mac does not serve adapters.
- A request uses the adapter only when it names it; every other request is answered by the base.

 

## 2 Give it its own temperatures

 

- Put the file beside the adapter’s weights as `decisio_adapter.json`, or give it with `--adapter-temperatures name=file` when the adapter’s folder is not yours to change.
- `temperatures` has one per type: `choice`, `noul` for yes/no, and `score`. A type the file does not list keeps the base’s temperature.
- `choice_bands` is optional: keys `lo-hi`, within 2 to 255 and not overlapping. A choice question is served at its band’s temperature; a count in no band is served at `temperatures.choice`, then at the base’s.
- Yes/no and score questions are not banded.
- An adapter with no file is served at the base’s temperatures, and the server says so when it starts.
- The file is checked before the engine is built, and an unusable one stops the start.

 

Fit the file from the adapter’s readouts on labelled items, one row per item (`{"type": ..., "probs": [...], "gold": <index>}`):

 

```
python -m decisio.serve.adapter_temperatures fit --reads reads.jsonl \
  --out decisio_adapter.json \
  --data "what the items are"
```

 

Shown, not run: it needs your adapter's readouts on your labelled items.

 

Fit on items that are not a benchmark’s: a temperature holds for the kind of items it was fitted on.

 

## 3 Ask with it

 

Name the adapter in the request’s `adapter` field:

 

```
curl -s http://127.0.0.1:8000/v1/systemone -H 'Content-Type: application/json' -d '{
  "state": "I was charged twice for the same order.",
  "adapter": "my-adapter",
  "questions": {"refund": {"type": "noul", "instructions": "Does the customer want a refund?"}}
}' -D - -o answer.json | grep -i '^x-decisio-adapter'
```

 

Shown, not run: it needs a server with an adapter loaded, on one NVIDIA card.

 

- The answer carries `"adapter"` and the `x-decisio-adapter` header when the adapter answered.
- An unknown name is answered 404, with the adapters that are loaded.

 

## 4 Check that it took

 

```
curl -s http://127.0.0.1:8000/health \
  | python3 -c 'import json, sys; h = json.load(sys.stdin); print(json.dumps({k: h.get(k) for k in ("adapter_temperatures", "adapter_identity")}, indent=1))'
```

 

Shown, not run: it needs a server with an adapter loaded, on one NVIDIA card.

 

`/health` shows each adapter’s temperatures in `adapter_temperatures`, and the hash of its weights and configuration in `adapter_identity`.

 

## 5 Know what it does to certificates

 

A certificate covers one [serving setup](https://opendecisio.com/docs/glossary/#serving-setup), and an adapter is part of it. The setup a certificate is checked against holds each loaded adapter’s name, weights hash and temperatures, so a different adapter, a retrained one or a changed temperature is a different setup: certify your [tasks](https://opendecisio.com/docs/glossary/#task) again on it. A request that names an adapter is never certified, and a question that a registered task matches is refused with an adapter.

 

## What next

 

- [Server flags](https://opendecisio.com/docs/flags/#every-flag): `--adapter` and `--adapter-temperatures` in full.
- [The HTTP API](https://opendecisio.com/docs/api/): the `adapter` field and its errors.
- [Certify answers](https://opendecisio.com/docs/tasks/certify/): certify a task again on the new setup.