Skip to main content

Documentation Index

Fetch the complete documentation index at: https://docs.usenexio.com/llms.txt

Use this file to discover all available pages before exploring further.

An engine version is an immutable, numbered release of an engine’s configuration. Once released, a version never changes — the behavior you test against a version is the behavior you get from it forever. Versions are numbered major.minor (for example 1.0, 1.1, 2.0):
  • A minor release (1.0 → 1.1) is wire-compatible: the request and response schemas are unchanged, so your existing integration keeps working. Minor releases carry improvements (better ranking, refreshed prompts).
  • A major release (1.x → 2.0) is a breaking change to the request or response schema. You adopt it deliberately by updating your integration and re-pinning — a major never reaches you automatically.

​
Pinning a version

Pass engine_version in the body of a run request to choose which version executes: 
POST /api/v1/engines/{engine_slug}/runs
{
  "engine_version": "1.3",
  "input": { ... }
}
The pin grammar is:
PinResolves toUse when
"1.3"Exactly version 1.3, frozen foreverYou need byte-for-byte reproducibility (compliance, audit, regression baselines)
"1.x"The latest released 1.x at the time of the requestYou want non-breaking improvements automatically
A bare major ("1") is rejected — it’s ambiguous between “exact” and “auto-track.” Three-tier versions ("1.0.0") are not supported. If you omit engine_version, the run uses the engine’s current configuration.
"1.x" guarantees schema compatibility, not identical output. A minor release can change ranking or wording as long as the request/response shape is unchanged. If you need output that never shifts, pin an exact version ("1.3").

​
Resolution is frozen at submit time

The version is resolved when you submit the run and stamped on it permanently. A release that happens while your run is queued never changes the running job. The resolved version is returned on the run — engine_version appears on GET /api/v1/runs/{run_id} and at the top level of data.run in webhook payloads — so you always know exactly which version produced a result.

​
Discovering versions

List an engine’s released versions and their changelogs: 
GET /api/v1/engines/{engine_slug}/versions
GET /api/v1/engines/{engine_slug}/versions/{version}
See Upgrading engine versions for the recommended workflow.