fable-agent/PHASES/phase-11-execution-engine.md

Phase 11: Execution Engine

Purpose: Load a skill, prepare context, execute steps with deliberate practice. TS Module: src/tier2-primitives/routines/execution-engine.ts

What It Does

• Loads the skill definition and context template
• Executes each step sequentially with lifecycle hooks
• Records timing, quality, and issues per execution
• Validates output against step criteria

Lifecycle Hooks

onBeforeStep(step, context)   // Prepare for step execution
onAfterStep(step, result, context)  // Process step result
onBeforeAll(skill, context)   // Pre-execution setup
onAfterAll(skill, result, context)  // Post-execution processing

Key Rules

• Each execution is fully recorded in the skill's history
• Quality score is calculated from step success ratio minus issue penalty
• Template variables ({{var}}) are substituted from context
• Validation criteria are checked after each step