Fan-Out / Fan-In Orchestration

When to Use

• OST has 2+ solutions for the same opportunity that need parallel exploration
• Independent delivery work items that can be parallelized
• Multiple research streams needed simultaneously

Workflow

1. Prepare (Lead Agent)

• Read .claude/canvas/opportunities.yml
• Identify solutions needing parallel work
• For each: identify riskiest assumption and design test

2. Fan-Out (Spawn Workers)

For each solution:

• Spawn subagent or Agent Team member
• Provide: clear task, read-only canvas context, worktree isolation, time bound
• Each worker runs independently

3. Fan-In (Collect Results)

• Collect all worker results
• Update ICE scores in canvas
• Run /mycelium:bias-check on combined findings
• Select winner(s) based on evidence
• Log decision in .claude/harness/decision-log.md

Leaf Bakeoff Mode

When comparing competing OST leaves for the same opportunity (two or more leaves that each have an untested riskiest assumption; no ICE gap is consulted):

• Each worker returns a structured scorecard (Four Risks + ICE + assumption test result + segment fit)
• Lead agent applies winner selection rules, which read the assumption-test verdicts: clear winner (one passes, the others fail), several pass in the same segment (tiebreaker), several pass in different segments (segment split, both advance), both fail (archive and re-evaluate). A leaf whose riskiest assumption failed is archived.
• The ICE total only orders which assumption is tested first. It never decides when to compare or which leaf wins (until 0.320.0 a "clear winner" was a leaf more than 20% ahead on ICE).
• Losers are archived to .claude/canvas/archived-solutions.yml with full evidence snapshot

See ${CLAUDE_PLUGIN_ROOT}/orchestration/leaf-bakeoff.md for the complete bakeoff protocol.

Rules

• Workers NEVER write to canvas (lead agent does)
• Workers NEVER progress diamonds
• Lead agent ALWAYS runs bias check on combined results
• Minimum 2 workers for meaningful comparison
• Maximum 3 leaves per bakeoff (respects L3 WIP ceiling)
• Inside an L3 (v0.301.0), the leaves are its set under the L2's target, and a clear winner is the candidate for its front_runner; recording it is the human's choice

See ${CLAUDE_PLUGIN_ROOT}/orchestration/agent-teams.md for full orchestration patterns.