Verifying by Consensus

Overview

Dispatch N agents to independently review the same subject. Collate findings:

• Common (N/N): All agents found → act immediately
• Exclusive (<N/N): Some agents found → cross-check validates

Agent Count Heuristics

Scope	Default N	Rationale
Single file change	2	Focused review, two perspectives sufficient
Multi-file feature	2-3	More surface area benefits from diversity
Architecture change	3	Different perspectives valuable
Security-sensitive	3+	Higher stakes warrant more eyes

Override via args: --count 3 or --agents "Explore,Plan,code-agent"

Agent Selection

1. Explicit args: If user provides --agents, use those
2. Available plugins: Check for specialized agents (cipherpowers code-review-agent, etc.)
3. Built-in agents: Use Claude's Explore, Plan agents with review prompts
4. Fallback: N instances of same agent with different perspective prompts

Process

Announce: "I'm using the verifying-by-consensus skill to verify [subject]."

Phase 1: Dispatch

1. Determine N (default 2, or from args)
2. Select agents (from args, plugins, or built-ins)
3. Start workflow: tsv run runbooks/verify.runbook.md
4. Dispatch agents with StepId prefix in description:

   Step(description="1.1 - Review [subject]", prompt="...", subagent_type="...")
   Step(description="1.2 - Review [subject]", prompt="...", subagent_type="...")
   

Hooks automate step binding:

Manual command	Hook trigger	When
tsv run --step 1.1	PostToolUse (Step)	StepId detected in description
tsv run --agent {id}	SubagentStart	Agent spawns

Subagent protocol:

• Write findings to .work/{date}-verify-{agentId}.md
• End response with STATUS: PASS or STATUS: FAIL

Phase 2: Collate

After all agents complete, dispatch collation:

• Read all N review files
• Compare findings across agents
• Categorize by consensus:
  • Common (N/N): All agents found this issue
  • Exclusive: Subcategorize by ratio (e.g., 2/3, 1/3)
• Write collation to .work/{date}-verify-collated.md

Present immediately:

Collation complete.

## Common (N/N)
[Issues all agents found - can implement now]

## Exclusive
### (N-1)/N
[Issues most agents found]
### 1/N
[Issues one agent found]

Cross-check starting for exclusive findings...

Phase 3: Cross-Check

Dispatch cross-check agent to validate ALL exclusive findings:

• For each exclusive issue, verify against ground truth
• Mark as: VALIDATED | INVALIDATED | UNCERTAIN
• Write to .work/{date}-verify-crosscheck.md

Present when complete:

Cross-check complete.

VALIDATED: X issues (should address)
INVALIDATED: X issues (can skip)
UNCERTAIN: X issues (user decides)

Phase 4: Complete

tsv complete

Output Files

All files saved to .work/:

• {date}-verify-{agentId}.md - Individual reviews
• {date}-verify-collated.md - Collation report
• {date}-verify-crosscheck.md - Cross-check results

Templates

Review template: ${CLAUDE_PLUGIN_ROOT}templates/verify-review.md Collation template: ${CLAUDE_PLUGIN_ROOT}templates/verify-collation.md