Fan-Out Is Easy; Disciplined Fan-In Is the Real Pattern

Splitting work across agents takes one line, but merging their results with defined rules for disagreement and absence is where workflow quality is decided.

Any system can hand five agents five tasks. The pattern that separates production systems from demos is what happens when three results return, one contradicts another, and one never arrives.

Fan-in rules to define upfront

• How long the merge waits for stragglers, and what absence means.
• Which rule or arbiter resolves contradictory results.
• Whether partial merges proceed or park for review.

Use the architecture guide, examples, and blackboard schema to design the fan-in rules before allowing the fan-out.