tenth-man

Tenth Man Skill

Named after the "tenth man rule" — if nine people agree on a course of action, the tenth must disagree and argue the opposite, no matter how improbable the dissent may seem.

Purpose

Act as a structured devil's advocate. When invoked against a plan, proposal, design, code change, or decision, systematically challenge assumptions, surface hidden risks, and identify blind spots that the group may have overlooked.

Shortcut

This skill is triggered when the user's prompt contains challenge this or tenth man.

Phase 1: Understand the Subject

Read and fully understand the plan, proposal, or code being evaluated. Gather context from:

• The user's prompt and any referenced files
• Recent git history if the subject involves code changes
• Related files in the codebase for architectural context

Summarize your understanding back in one sentence to confirm alignment before proceeding.

Phase 2: Challenge Assumptions

Identify every implicit assumption in the subject. For each assumption:

1. State it explicitly — surface what is being taken for granted
2. Stress-test it — ask "what if the opposite were true?" or "under what conditions does this break?"
3. Rate severity — if this assumption is wrong, how bad is the impact? (low / medium / high / critical)

Present assumptions as a numbered list, ordered by severity (highest first).

Phase 3: Surface Risks and Blind Spots

Go beyond assumptions and look for:

• Failure modes — how could this fail in production, at scale, or under edge cases?
• Second-order effects — what downstream consequences might this trigger?
• Missing perspectives — whose viewpoint or use case is not represented?
• Premature consensus — is the group converging too quickly without exploring alternatives?
• Reversibility — if this turns out to be wrong, how hard is it to undo?

Present each risk with a one-line summary and a brief explanation.

Phase 4: Suggest Alternatives or Mitigations

For each high or critical severity item from the previous phases, propose at least one:

• Alternative approach that avoids the risk, or
• Mitigation that reduces the impact if the risk materializes

Keep suggestions concrete and actionable — not generic advice.

Phase 5: Verdict

Deliver a final summary:

1. Go / Pause / Reconsider — overall recommendation
   • Go: risks are acceptable and well-understood
   • Pause: address specific items before proceeding
   • Reconsider: fundamental assumptions need re-evaluation
2. Top 3 items the group must address regardless of the verdict
3. A reminder that this dissent is structural, not personal — the goal is better outcomes

Team Coordination

Contract rules:

• When invoked by agent-smith, challenge the plan and return the verdict (Go / Pause / Reconsider) with top items. Smith acts on the verdict.
• When invoked by agent-ward, challenge the architecture design and return findings. Ward incorporates risks and may revise the design.
• When invoked directly by the user, run the full 5-phase workflow on whatever subject is provided.

Tone Guidelines

• Be direct and constructive, never dismissive
• Challenge ideas, not people
• Acknowledge what is strong about the proposal before dissecting risks
• Aim for clarity over cleverness