ensemble

name	ensemble
description	Coordinates multiple runtime lanes for tasks no single lane covers adequately. Triggered exclusively by ModelRouter. Three modes: Sequential (B needs A output), Independent (parallel, independent artifacts), Cross-check (both run same task, Grader compares). Cross-check required for Attestation and Audit modes. Writes combined receipt naming all lanes used.

Ensemble

You are triggered by ModelRouter only — never self-activate. You coordinate multiple lanes and write one combined receipt.

What this skill does

Coordinates multiple runtime lanes for tasks no single lane covers adequately. Triggered exclusively by ModelRouter. Three modes: Sequential (B needs A output), Independent (parallel, independent artifacts), Cross-check (both run same task, Grader compares). Cross-check required for Attestation and Audit modes. Writes combined receipt naming all lanes used.

When to use

Triggered by ModelRouter when any of four conditions met:

1. Task spans multiple build targets simultaneously
2. No single capability covers all required capabilities
3. Verification mode is Attestation or Audit
4. Confidence below 0.7 after single-lane attempt

Coordination modes

Sequential — Lane B requires Lane A output before starting. Use when: output dependency between lanes.

Independent — Lanes run in parallel, produce separate artifacts. Use when: task is parallelizable with no shared output.

Cross-check — Both lanes run the same task independently. Grader (from Reviewer) compares outputs. Use when: verification mode is Attestation or Audit, or confidence gap between lanes.

Cross-check is mandatory for Attestation and Audit verification modes.

Reference Routing

Situation	Reference
Ensemble receipt write	engine/shared/references/script-delegation-contract.md → receipt-writer.py --type generic

Output contract

Combined receipt names all lanes, mode used, and individual lane outcomes:

{
  "module": "ensemble",
  "mode": "Sequential|Independent|Cross-check",
  "lanes": [
    { "capability": "string", "outcome": "PASS|FAIL", "artifacts": [] }
  ],
  "combined_outcome": "PASS|FAIL",
  "cross_check_agreement": true
}

Cross-check: if lanes disagree, cross_check_agreement: false — route to Reviewer.

What not to do

• Do not self-activate — ModelRouter triggers only
• Do not skip Cross-check for Attestation/Audit verification modes
• Do not write separate receipts per lane — one combined receipt only