---
name: evolv-process-systems-control
description: Design and review system-level control behavior across EVOLV process nodes. Use when coordinating multi-node interactions, mode/state transitions, parent-child registration flows, control loops, and complex process sequencing spanning reactors, valves, pumps, settlers, and machine groups.
---

# EVOLV Process Systems Control

## Mission
Preserve stable system-wide behavior across interacting Node-RED nodes and process assets.

## Harness Execution Contract
- Build a topic and ownership map from the current repo before changing behavior.
- Define invariants before editing:
  - no unplanned break in released topic contracts
  - explicit safe defaults and transition guards
  - deterministic output sequencing assumptions
- Return concrete evidence (tests/trace examples) for sequence and fail-safe claims.

## Scope
- Cross-node interactions via `msg.topic`
- Parent-child registration contracts (`registerChild` and related topics)
- Mode management and sequencing in node wrappers/domain classes

## Message/Port Convention Baseline
Many EVOLV nodes use this output convention:
- output 0: process message
- output 1: database/influx message
- output 2: parent/registration/control plumbing

Preserve topic stability once released (`registerChild`, `setMode`, `setScaling`, etc). If a topic contract changes, define a migration path.

## Control Workflow
1. Map control boundaries and authority (who commands whom).
2. List topic contracts and payload schemas.
3. Verify state/mode transition logic for race/conflict conditions.
4. Define safe startup, shutdown, and failover behavior.
5. Confirm tick timing and output ordering assumptions.

## Design Rules
- Keep topic names stable once released.
- Use explicit transition guards and default-safe modes.
- Avoid hidden cross-coupling between unrelated assets.
- Make control intent observable in outputs/status.

## Test Expectations
Add tests for:
- normal sequence transitions
- out-of-order messages
- duplicate child registration and dedupe behavior
- fail-safe behavior under missing dependencies

## Deliverables
Return:
- system interaction map (topics + ownership)
- transition table and safety guards
- changed files/tests
- unresolved control hazards with mitigation suggestions

Decision interview triggers:
- any topic rename/removal or payload schema break
- authority changes across parent/child nodes
- startup/shutdown sequencing changes with operational impact