Pattern Proposal: Service Facade Application Boundary

Summary

Provides high-level application service facades encapsulating domain engines for presentation layer consumers.

Candidate Pattern

• ID: service-facade-application-boundary
• Classification: architectural
• Maturity: strategic_direction
• Type: emerging

Observed Signals

No specific signals listed.

Evidence

Supporting Evidence

• src/cas_runner/governance/governance_action_service.py (GovernanceActionService) - Encapsulates GovernanceActionEngine and provides entry points for CLI runners
• src/cas_runner/cli.py (main) - Delegates commands to application services and FlowRunner

Scope Assessment

• Evidence Strength: high
• Confidence: high
• Applies to: ideas-to-life-cas

Rationale

• Intent: Isolate the CLI commands and flow runners from lower-level action engines, registries, and metric collectors.
• Context: CLI handlers need to trigger complex governance actions without orchestrating internal engine dependencies.
• Force: CLI code should remain thin and focused on CLI parameter parsing.
• Force: Internal domain logic should not leak into CLI interface scripts.

Traceability

Artifact source: proposed-patterns