10th Man Protocol MCP

When everyone agrees, someone has to disagree.

Adversarial review system for autonomous AI coding agents. Before your agent executes a critical change, 3 independent contrarian reviewers challenge the proposal — catching what a solo agent misses.

npm install -g tenth-man-mcp
claude mcp add tenth-man -- npx tenth-man-mcp

That's it. On first run, the protocol auto-injects a behavioral trigger into your CLAUDE.md and sets up .tenth-man/ in your repo (gitignored).

How It Works

When your agent is about to make a critical change — touching auth, refactoring architecture, modifying 3+ files, running migrations — the protocol spawns 3 independent reviewers:

| Agent | Role | What They Do | |-------|------|-------------| | 🔴 Devil's Advocate | Break it | Finds every failure mode, race condition, security hole | | 🟡 Architecture Critic | Question it | Evaluates structural impact, coupling, pattern consistency | | 🟢 Pragmatist | Reality-check it | Rollback strategy, scope creep, simpler alternatives |

Each agent reads the codebase independently in an isolated context window. Zero opinion contamination between reviewers.

Agent Resolution

The protocol uses the best available models, falling back gracefully:

| Available CLIs | What Happens | |---|---| | Codex + Gemini | All 3 run in parallel (~1-3 min) | | One external agent | External + 2 isolated Claude subagents (~2-4 min) | | Neither | 3 isolated Claude subagents (~3-5 min) |

Models: gpt-5.3-codex, gemini-3-pro-preview, claude-opus-4-6. Top-tier only. This is for people who need reliability over cost.

Workflow

Standard Mode (default)

Agent detects critical change
    → Calls tenth_man_review
    → "🔟 10th Man Protocol activated — CRITICAL severity.
        Spawning 3 agents... expect 2-5 minutes."
    → Review complete
    → Agent: "3 agents reviewed your JWT refactor:
        🔴 Devil's Advocate BLOCKS — token refresh race condition
        🟡 Architecture Critic says PROCEED — recommends adapter pattern
        🟢 Pragmatist says PROCEED — wants it split into 3 phases
        How would you like to proceed?"
    → You: "go ahead, address the race condition"
    → Agent creates execution plan → you confirm → agent executes
    → Everything archived to .tenth-man/history/

Auto Mode

Same review, no pauses. Agent incorporates findings into its plan and proceeds immediately. For fire-and-forget workflows.

After completion, the agent includes a one-liner:

⚠️ 10th Man: Proceed with changes. 2 critical issues addressed, 4 recommendations.

Directory Structure

.tenth-man/                     # Auto-added to .gitignore
  config.json                   # Optional repo config
  active/
    REVIEW.md                   # Current review (standard mode)
    PLAN.md                     # Current plan (after approval)
  history/
    2026-02-12T14-30-00Z_a3f8c2/
      review.md
      plan.md
      outcome.json
  index.json                    # Manifest for history queries

Requirements

• Node.js ≥ 20
• Claude Code (host agent)
• Optional: Codex CLI for cross-model review
• Optional: Gemini CLI for cross-model review

Bypass / YOLO Mode

If you run Claude Code with --dangerously-skip-permissions, the protocol defaults to standard mode (waits for approval) — which means the agent will pause and wait for you. If you're walking away, set auto mode once:

# In Claude Code, run:
Use tenth_man_configure with default_mode "auto"

Or create .tenth-man/config.json in your repo:

{
  "default_mode": "auto"
}

Now the protocol reviews, plans internally, executes, and archives — no pauses. You come back to finished work + full audit trail.

Why not auto-detect? Claude Code cannot detect whether it's running in bypass mode. It always thinks it's interactive. So this is a one-time config per repo.

Reference

MCP Tools

tenth_man_review

Main entry point. Triggers adversarial review.

{
  "task_description": "Refactor auth from session-based to JWT",
  "proposed_changes": "Replace express-session with jsonwebtoken...",
  "affected_files": ["src/auth/*", "src/middleware/auth.ts"],
  "severity": "critical",
  "mode": "standard"
}

Severity levels:

• high — 3+ files affected
• critical — Auth, data, architecture changes
• blocker — Breaking changes, migrations

Modes:

• standard — Review → user approval → plan → user confirms → execute
• auto — Review → agent plans internally → execute → audit trail

tenth_man_compile

Finalizes review after Claude subagent results are collected. Called automatically by the host agent after spawning subagents.

tenth_man_configure

View or update repo-level settings.

{
  "timeout_seconds": 240,
  "default_mode": "auto",
  "available_agents": ["codex"]
}

tenth_man_history

Query past audits.

{
  "last_n": 10,
  "severity": "critical"
}

Configuration

Optional .tenth-man/config.json:

{
  "available_agents": ["codex", "gemini"],
  "timeout_seconds": 180,
  "default_mode": "standard",
  "auto_trigger_patterns": [
    "**/auth/**",
    "**/migrations/**",
    "**/*.schema.*"
  ]
}

License

MIT