discovery(orchestration): low-utilization composability — SuccessCriteriaEvaluator + CollaborationCoordinator are single-caller modules #6832

Discovered during

Audit of issue #4048 closure (2026-05-04).

Finding

Two modules in enhanced_orchestration/ are well-implemented but coupled to a single caller, missing composability opportunities:

1. SuccessCriteriaEvaluator (234 LOC)

enhanced_orchestration/success_criteria.py implements a generic, weighted criteria evaluator (#3293) — exit code, output pattern, custom checks. Used only by `WorkflowRunner` internally.

This is a generic capability that should be available to:

• The canonical `Orchestrator` (no current path)
• DAG workflows via `DAGExecutor` (no current path)
• Any new execution mode

2. CollaborationCoordinator (63 LOC)

enhanced_orchestration/collaboration_coordinator.py is a thin Redis pub/sub wrapper (#5058 extraction). Used only by `WorkflowRunner`.

At 63 LOC and one caller, the extraction has overhead but no current payoff. Either:

• Inline back into `WorkflowRunner` (reverse the refactor(orchestrator): three overlapping workflow execution paths in single Orchestrator class #5058 split for this specific collaborator)
• OR expose it as a top-level coordination primitive used by other execution modes

Why it matters

Composability is the value-add of a decomposed orchestrator. If decomposed parts only have one caller, the decomposition cost (extra files, extra imports, extra tests) isn't earning its keep.

Recommendation

For `SuccessCriteriaEvaluator`:

• Promote to `orchestration/success_criteria.py` (lower layer)
• Wire into `WorkflowExecutor` and `DAGExecutor` as an optional post-step hook
• Document the criteria DSL in `orchestration/init.py`

For `CollaborationCoordinator`:

• Either inline back into `WorkflowRunner` (if no other consumer is planned)
• Or promote to `orchestration/coordination.py` and document as a primitive

Acceptance criteria

• `SuccessCriteriaEvaluator` is callable from at least 2 distinct execution paths
• `CollaborationCoordinator` either has ≥2 callers OR is inlined back into its single caller
• Existing `WorkflowRunner` tests pass unchanged

Priority

P3 — composability hygiene, no functional impact today.