Orchestration · Software component
Dependency-Ordered Executor
Software componentOrchestrationOrchestration & ToolsVariation point (abstract)arc:DependencyOrderedExecutor
An abstract workflow orchestrator that starts each agent only after all of its declared dependencies have completed, externally imposing execution order regardless of agent logic.
Responsibility. Enforces declared dependency order during multi-agent execution.
Also known as: Dependency enforcement, Ordered multi-agent execution
Variant of Workflow Orchestrator abstract
When to choose. Choose over spawning all agents concurrently whenever agents consume each other's outputs, since probabilistic start ordering violates dependencies under load.
Variants
| Variant | When to choose |
|---|---|
| Asynchronous Dependency-Chaining Executor | Choose when phase-barrier latency proves unacceptable and maximal parallelism is needed; accepts higher complexity and cascading cancellation of dependents when an agent fails. |
| Phase Barrier Executor | Choose when simple, robust failure semantics matter more than maximal parallelism: a failure in a phase stops the workflow immediately, at the cost of waiting for the slowest agent of each phase. |
Relationships
is configured by structural
invokes dependency
emits telemetry to dynamic
is constrained by control
- Deadlock Controller abstract Ch8.2A
orchestrates control
- Worker Agent abstract Ch8.2A
alternative to variability
Design guidance
- MUST enforce dependency order deterministically rather than rely on timing, which varies with load, garbage collection and scheduling.
- SHOULD record phase or dependency transitions as trace events so latency and failure hotspots are visible.
Quantitative guidance
As stated by the sources; verify before use.
- Out-of-order execution caused 40% of coordination failures (32 of 80 failed traces; ~16/day) when all agents were spawned at once (Ch8.2A).
- Coordination failure rate 8.0% -> 0.3% (96% reduction); MTTD 45 s -> 5 s; MTTR 2.5 min -> 15 s after dependency graph, barriers and optimistic locking (Ch8.2A).
Classification
- Patterns
- Orchestrator-imposed ordering
- Technologies
- OpenTelemetry
- Quality attributes
- Reliability (ISO/IEC 25010 | NIST AI RMF: valid and reliable)Functional suitability: correctness and validity (ISO/IEC 25010 | NIST AI RMF: valid)
- Risks mitigated
- Out-of-order execution producing incomplete outputsCoordination bugs under high concurrency
Sources
- Ch8.2A: T. Nguyen, "Error Rates and Reliability," in Mastering Agentic AI Systems: Guide for the NVIDIA NCP-AAI Exam, 1st ed. 2026, ch. 8.2A. ISBN: 9798244538229.