Cognition · Software component

Plan Constraint Propagator

Software componentCognitionCognition & Memoryarc:PlanConstraintPropagator

A planning component that incrementally checks ordering, causal-link, resource, temporal and state constraints after each decomposition step and forward-checks preconditions to trigger early backtracking.

Responsibility. Detects constraint inconsistencies in the task network as early as possible.

Also known as: Constraint propagation, Forward checker, Plan validity checker

Direct neighbourhood (hover for relationship types)

Relationships

is invoked by dependency

HTN Planner Ch5.4

reads dependency

Design guidance

SHOULD balance constraint-checking granularity against search-space reduction; per-step overhead exceeds savings on small networks.

Quantitative guidance

As stated by the sources; verify before use.

Checking all pairwise orderings, resource conflicts and causal links costs O(n^2) per step for n tasks (Ch5.4).

Classification

Patterns: Constraint propagationForward checkingEarly failure detectionCausal-link protection
Quality attributes: Performance efficiency (ISO/IEC 25010)Functional suitability: correctness and validity (ISO/IEC 25010 | NIST AI RMF: valid)
Risks mitigated: Circular ordering dependenciesResource conflictsMissing preconditions discovered only at primitive levelMissing inter-agent data dependencies

Sources

Ch5.4: T. Nguyen, "Hierarchical Planning Fundamentals," in Mastering Agentic AI Systems: Guide for the NVIDIA NCP-AAI Exam, 1st ed. 2026, ch. 5.4. ISBN: 9798244538229.