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Separating Read and Write Phases in Automation Workflows

Why Phase Separation Matters

Mixed read/write scripts are hard to reason about under failure.

When discovery, planning, and execution are blended:

  • Operators cannot review intended changes clearly
  • Debugging is harder after partial execution
  • It becomes difficult to reproduce run decisions

Phase separation makes behaviour inspectable and controllable.

  1. Discovery: collect live facts
  2. Validation: enforce policy and prerequisites
  3. Planning: compute diff and proposed actions
  4. Approval: optional human gate
  5. Execution: apply approved plan only
  6. Verification: confirm intended state and service health

Each stage should emit structured artifacts.

Plan Artifact Pattern

Before any write, produce a plan document containing:

  • Target list and scope constraints
  • Pre-flight status per target
  • Intended changes per target
  • Risk classification and rollback option
  • Approval metadata (if required)

Execution then consumes this immutable plan.

Operational Benefits

Phase separation improves:

  • Safety: easier to block unsafe writes
  • Explainability: clear reason for each action
  • Repeatability: same plan can be re-run predictably
  • Auditability: artifacts show what was intended vs applied

Production Checklist

  • Read and write logic are implemented as separate phases
  • Plan output is reviewable before execution
  • Execution is blocked without a valid plan artifact
  • Verification runs after writes and is persisted
  • Operators can replay a run from artifacts

Anti-Patterns

  • Auto-generating and applying plan in one opaque function
  • No durable plan artifact
  • Mutating target scope during execution phase
  • Skipping verification due to time pressure

Key Takeaway

Separating read and write phases turns automation from a script into a reliable operational system.

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