> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fastino.ai/llms.txt
> Use this file to discover all available pages before exploring further.
> ## Agent Instructions
> Use https://docs.fastino.ai/openapi.json as the source of truth for customer-facing routes. For GLiDE decision inference, call POST https://api.fastino.ai/v1/systemone with model fastino/glide. Do not infer undocumented routes. Read API keys from FASTINO_API_KEY and never embed credentials in code, logs, or reports.
# GLiDE inference with /v1/systemone
> Authenticate, choose a Noul, Choice, or Score question, call POST /v1/systemone, and act on GLiDE probabilities and confidence.
```text theme={null}
POST https://api.fastino.ai/v1/systemone
```
This is the inference endpoint for **GLiDE**. Send a non-empty `state` and one or more named,
typed `questions`; read structured decisions from `answers`. GLiDE does not use
`/v1/chat/completions`, `messages`, or a GLiNER `schema`.
## Authenticate
Create an API key in [Fastino Settings](https://agent.fastino.ai/api-keys), then set:
```bash theme={null}
export FASTINO_API_KEY="fast_sk_..."
```
Send it with every request:
```http theme={null}
X-API-Key: $FASTINO_API_KEY
Content-Type: application/json
```
`Authorization: Bearer $FASTINO_API_KEY` is also accepted. Use one style consistently.
## Choose a question type
Every question is single-label and returns probabilities. Choose the primitive from the
answer shape your code needs:
| Primitive | Use when | `criteria` shape | Primary result |
| - | - | - | - |
| [Noul](/concepts/glide-noul) | The answer is yes or no | Optional `{"true": "...", "false": "..."}`; defaults to Yes/No | `noul`, the probability of true |
| [Choice](/concepts/glide-choice) | Exactly one unordered option should win | Object mapping option keys to descriptions | `choice` plus `probabilities` |
| [Score](/concepts/glide-score) | The answer belongs on an ordered scale | Ordered array of level descriptions | `score`, `expected_level`, and `probabilities` |
There is no multi-label primitive. Ask multiple independently named questions in one request
when you need several judgments about the same state.
## Request
Use `fastino/glide`. The response echoes the engine name as `glide`.
The non-empty situation to evaluate. Use a string for one passage, an object for labeled
fields, or an array for an ordered sequence of messages or records.
A non-empty object keyed by names you choose. Each value must contain `type` and
`instructions`; Choice and Score also require `criteria`. The same keys appear under
`answers` in the response.
### Complete request
```bash theme={null}
curl --max-time 300 -s https://api.fastino.ai/v1/systemone \
-H "X-API-Key: $FASTINO_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "fastino/glide",
"state": "Refund request: the receipt is attached, the purchase was 10 days ago, and refunds are allowed within 30 days.",
"questions": {
"refund_allowed": {
"type": "noul",
"instructions": "Does this request qualify for a refund?",
"criteria": { "true": "Qualifies", "false": "Does not qualify" }
}
}
}'
```
## Response
```json theme={null}
{
"model": "glide",
"answers": {
"refund_allowed": {
"type": "noul",
"noul": 0.99767683794902,
"confidence": 0.9953536758980399
}
},
"usage": { "input_tokens": 89, "output_tokens": 1 }
}
```
`answers` uses the question keys from your request. For this Noul:
* `noul` is the probability that the `true` criterion holds. It is not a boolean.
* `confidence` is certainty about either outcome: `|2 × noul − 1|`.
* Tune action thresholds on representative data. Do not assume `0.5` is the right business
threshold.
Choice and Score return different fields. See their primitive pages for exact response shapes
and integration examples.
## Limits and unsupported shapes
* Each rendered question prompt (`state` plus that question) must fit within **40,000
tokens**.
* Choice and Score accept at most **255 options or levels**.
* `usage.input_tokens` sums the internal passes for all questions, so it can exceed 40,000
even though every individual rendered prompt fits.
* One request evaluates one shared `state`; put multiple questions under `questions`.
* `/v1/systemone` does not stream and does not accept a batch of independent states.
* GLiDE does not currently support fine-tuned deployment IDs.
See [GLiDE Reference](/concepts/decision-models) for state-shape guidance, confidence
formulas, and a mixed Choice/Score request.
## Errors
| Status | Likely cause | Action |
| - | - | - |
| `400` | Prompt exceeds the context window or another inference input is invalid | Shorten the state or correct the question |
| `401` | Missing, malformed, or invalid API key | Export a valid `fast_sk_...` key |
| `402` | Insufficient credits, funding required, or an owner-set daily/monthly spend limit | Add credits or adjust the spend limit |
| `403` | Payment method, card verification, credit ceiling, or account policy denial | Resolve the billing or account requirement |
| `404` | Unknown model or a model that only supports chat completions | Use `fastino/glide` |
| `422` | A required field is missing, a value has the wrong shape, or an extra field was sent | Read and correct the field-level validation details |
| `425` | Deployment is warming | Retry after the indicated delay |
| `429` | Rate or capacity limit | Respect `Retry-After` and retry with backoff |
| `503` | Temporary provider or serving failure | Retry before treating it as terminal |
Use a read timeout of at least 300 seconds and bounded backoff for `425`, `429`, and `503`.
Do not retry `401`, `402`, `403`, `404`, or `422` without correcting the underlying problem.
## Continue learning
Understand state shapes, limits, confidence, and combining multiple questions.
Integrate a yes/no probability.
Route to one named option.
Evaluate an ordered rubric.