Cancel an evaluation run
⚠️
Preview — this feature is being built; the design below is the spec.
POST https://app.syntic.ai/v1/evals/runs/{eval_run_id}/cancelStop a run. Items already generated and graded stay in the results and are billed.
For how this fits into a full workflow, see Evaluations.
Headers
| Header | Required | Value |
|---|---|---|
Authorization | Yes | Bearer <key>: a private inference key (sk_live_...). See Authentication. |
syntic-beta | Yes, while in preview | evals-2026-12-01. Without it the call fails with 400 beta_required. See Versioning. |
Idempotency-Key | No | Up to 255 characters. Retrying with the same key within 24 hours returns the first result instead of acting twice. See Idempotency. |
Path parameters
| Parameter | Type | Description |
|---|---|---|
eval_run_id | string | Starts with evrun_. |
Response
200 OK, Content-Type: application/json
{
"id": "evrun_01JD35D7F9H1K3M5P7R9",
"type": "eval_run",
"name": "shorter system prompt vs baseline",
"dataset_id": "evds_01JD13B5D7F9H1K3M5P7",
"status": "canceled",
"variants": [
{
"label": "baseline",
"model": "Amara S1.2",
"prompt_version": "support-v12"
},
{
"label": "short",
"model": "Amara S1.2",
"prompt_version": "support-v13"
}
],
"grader_ids": [
"evgr_01JD46E8G0J2L4N6Q8S0"
],
"progress": {
"total": 400,
"done": 131,
"errored": 0
},
"summary": null,
"created_at": "2026-11-05T10:00:00Z",
"finished_at": "2026-11-05T10:09:40Z"
}| Field | Type | Description |
|---|---|---|
variants | array | Up to 4 prompt and model combinations, each run on every item. |
progress | object | Items done per variant summed across variants. |
summary | array | Per variant: pass rate, mean score, mean output length and cost, once finished. |
status | string | queued, running, succeeded, failed or canceled. |
Examples
curl -sS -X POST "https://app.syntic.ai/v1/evals/runs/evrun_01JD35D7F9H1K3M5P7R9/cancel" \
-H "Authorization: Bearer $SYNTIC_API_KEY" \
-H "syntic-beta: evals-2026-12-01" \
-H "Idempotency-Key: 8d6f0c1e-4b2a-4a57-9f0e-2f1d3c4b5a69"Errors
Errors use the error envelope and carry a request_id. Codes specific to this operation:
| Status | type | code | When |
|---|---|---|---|
| 400 | invalid_request_error | beta_required | The syntic-beta header is missing. |
| 409 | conflict_error | run_finished | The run already ended. |
| 404 | not_found_error | eval_run_not_found | No run with this id. |
| 401 | authentication_error | invalid_api_key | The key is missing, unknown, revoked or expired. |
| 429 | rate_limit_error | rate_limited | Too many requests; wait for Retry-After. See Rate-limit headers. |
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