Engine Primitives
Engine Primitives are pre-built, security-vetted building blocks you attach to your Yoke's transitions, states, and fields. Each one is a small, composable unit of "engine" logic that you configure via the Yoke Studio without writing any code.
Pick a primitive below to learn how to use it:
| Primitive | What it does | Tier |
|---|---|---|
| Aggregator | Roll up child records into a parent field — sum, count, average. | Every plan |
| Notifier | Send email or webhook on transitions, state changes, or field updates. | Free (email) / Pay-as-you-go (webhook) |
| Scheduler | Run transitions or other primitives on a cron schedule. | Pay-as-you-go |
| SLA Timer | Escalate stuck jobs after a fixed duration. | Pay-as-you-go |
| PDF Generator | Render PDFs from typst templates on transitions. | Pay-as-you-go |
| Approval Gate | Block transitions behind N-of-M approver votes. | Pay-as-you-go |
| Field Compute | Compute virtual fields at read time using formulas. | Every plan |
| Field Mutator | Atomically increment, decrement, or set a field — with bounds. | Every plan |
| Record Spawner | Create entity records as a side effect of events. | Pay-as-you-go |
| Cross-Entity Transition | Fire an FSM event on a related entity's job. | Pay-as-you-go |
Trigger predicates
Every primitive that fires on entity changes can use an optional trigger predicate to filter exactly when it runs — fire on a boolean edge, on a threshold crossing, or only when a specific value appears.