Agent Output Guard MCP Server 🛡️

The first MCP server designed specifically to solve coordination failures in multi-agent systems. Built by Agenson Horrowitz based on the MAST study showing 36.9% of multi-agent failures are coordination breakdowns.

🚨 The Multi-Agent Coordination Crisis

41-86% of multi-agent systems fail. But here's what nobody talks about: 36.9% of these failures aren't bugs—they're coordination breakdowns.

• Agent A works perfectly ✅
• Agent B works perfectly ✅
• They fail when they interact ❌

The problem? No systematic validation at the handoff boundary.

💡 Why This Exists

Current debugging tools assume single-agent failures. But multi-agent breakdowns happen at the handoff layer where:

• Data formats don't match expectations
• Content is hallucinated or stale
• Context gets lost in translation
• Receiving agents can't process what they're given

Agent Output Guard solves this with zero LLM costs—pure computation.

⚡ Key Features

🛡️ Zero LLM Cost Operation

• Pure computational algorithms
• No API calls to language models
• Scales infinitely without incremental costs
• Perfect for high-volume agent interactions

📊 Evidence-Based Design

• Built on MAST study data (1,642 multi-agent traces)
• Addresses the 36.9% coordination failure rate
• Validates the patterns that cause 72-86% token duplication
• Solves real problems, not theoretical ones

🎯 5 Critical Validation Tools

1. JSON Schema Verification - Ensure data structure compliance
2. Hallucination Detection - Spot uncertainty and fabrication markers
3. Data Freshness Validation - Check timestamps and staleness indicators
4. Cross-Reference Checking - Compare data across multiple agent sources
5. Output Consistency Scoring - Calculate overall reliability metrics

🚀 Installation

Claude Desktop Configuration

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "agent-output-guard": {
      "command": "npx",
      "args": ["@agenson-horrowitz/agent-output-guard-mcp"]
    }
  }
}

Cline Configuration

Add to your Cline MCP settings:

{
  "mcpServers": {
    "agent-output-guard": {
      "command": "npx", 
      "args": ["@agenson-horrowitz/agent-output-guard-mcp"]
    }
  }
}

Via npm

npm install -g @agenson-horrowitz/agent-output-guard-mcp

Via MCPize (One-click deployment)

Deploy instantly on MCPize with built-in billing and authentication.

🛠️ Tools Reference

1. verify_json_schema

Validate agent data against expected schemas with confidence scoring.

{
  "data": {"user_id": "123", "score": 85.5},
  "schema": {
    "type": "object",
    "properties": {
      "user_id": {"type": "string"},
      "score": {"type": "number", "minimum": 0, "maximum": 100}
    },
    "required": ["user_id", "score"]
  },
  "strict_validation": false,
  "source_agent": "data_collector_v2"
}

Returns: Validation status, confidence score, detailed errors, compliance metrics.

2. detect_hallucination_markers

**Scan agent output for u

... View full README on GitHub