MCP Kernel Server

Native Safety for Claude Desktop - Agent OS kernel primitives via Model Context Protocol (MCP)

This server exposes Agent OS capabilities through MCP, enabling Claude Desktop and other MCP-compatible clients to use kernel-level AI agent governance.

The Problem

Claude generates code without safety guarantees. It can suggest:

• DROP TABLE users - deleting production data
• Hardcoded API keys and secrets
• rm -rf / - destructive file operations

The Solution

Agent OS MCP Server provides safety verification that Claude calls before executing code:

[Claude generates code]
        ↓
[Calls verify_code_safety tool]
        ↓
[Agent OS returns: BLOCKED - Destructive SQL]
        ↓
[Claude explains why and suggests safer alternative]

Quick Start

Claude Desktop Integration (60 seconds)

1. Install the server:

pip install agent-os[mcp]

2. Add to Claude Desktop config:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "agent-os": {
      "command": "mcp-kernel-server",
      "args": ["--stdio"]
    }
  }
}

3. Restart Claude Desktop. You now have access to 8 safety tools!

Available Tools

verify_code_safety - Code Safety Check ⭐ NEW

The primary tool for Claude Desktop. Checks if code is safe before execution.

{
  "name": "verify_code_safety",
  "arguments": {
    "code": "await db.query('DROP TABLE users')",
    "language": "javascript"
  }
}

Returns:

{
  "safe": false,
  "violations": [
    {
      "rule": "drop_table",
      "severity": "critical",
      "message": "Destructive SQL: DROP operation detected",
      "alternative": "Consider using soft delete or archiving instead of DROP"
    }
  ],
  "blocked_reason": "Destructive SQL: DROP operation detected"
}

cmvk_review - Multi-Model Code Review ⭐ NEW

Review code across multiple AI models for bugs, security, and best practices.

{
  "name": "cmvk_review",
  "arguments": {
    "code": "function processPayment(userId, amount) {...}",
    "language": "javascript",
    "focus": ["security", "bugs"]
  }
}

Returns:

{
  "consensus": 0.67,
  "reviews": [
    {"model": "gpt-4", "passed": true, "issues": []},
    {"model": "claude-sonnet-4", "passed": false, "issues": [...]},
    {"model": "gemini-pro", "passed": true, "issues": []}
  ],
  "recommendation": "Based on multi-model review:\n1. Missing error handling..."
}

get_audit_log - Retrieve Audit Trail ⭐ NEW

Get the safety audit trail for compliance and debugging.

{
  "name": "get_audit_log",
  "arguments": {
    "limit": 20,
    "filter": {"type": "blocked"}
  }
}

cmvk_verify - Cross-Model Claim Verification

Verify claims across multiple AI models to detect hallucinations.

{
  "name": "cmvk_verify",
  "arguments": {
    "claim": "The capital of France is Paris",
    "threshold": 0.85
  }
}

kernel_execute - Governed Execution

Execute actions through the kernel with policy enforcement.

{
  "name": "kernel_execute",
  "arguments": {
    "action": "database_query",
    "params": {"query": "SELECT * FROM users"},
    "agent_id": "analyst-001",
    "policies": ["read_only", "no_pii"]
  }
}

iatp_sign - Trust Attestation

Sign agent outputs for inter-agent trust.

iatp_verify - Trust Verification

Verify trust before agent-to-agent communication.

iatp_reputation - Reputation Network

Query or modify agent reputation.

Demo: Using with Claude Desktop

After installation, try this in Claude Desktop:

You: "Write a script to clean up old user data"

Claude: (generates code, then calls verify_code_safety)

Agent OS returns: BLOCKED - Destructive SQL detected

Claude: "I generated the code, but Agent OS blocked it for safety. The DELETE statement would remove data permanently. Here's a safer approach using soft deletes..."

Available Resources

URI Template	Description
vfs://{agent_id}/mem/working/{key}	Ephemeral working memory
vfs://{agent_id}/mem/episodic/{session}	Experience logs
vfs://{agent_id}/policy/{name}	Policies (read-only)
audit://{agent_id}/log	Audit trail (read-only)

Available Prompts

governed_agent

Instructions for operating as a governed agent.

verify_claim

Template for CMVK verification.

safe_execution

Template for safe action execution.

Stateless Design (MCP June 2026 Compliant)

This server is stateless by design for horizontal scaling:

• ✅ No session state maintained
• ✅ All context passed in each request
• ✅ State externalized to backend storage
• ✅ Horizontally scalable

Configuration Options

mcp-kernel-server --stdio                    # Claude Desktop (default)
mcp-kernel-server --http --port 8080         # Development
mcp-kernel-server --policy-mode strict       # Policy mode: strict|permissive|audit
mcp-kernel-server --cmvk-threshold 0.90      # CMVK confidence threshold

Development Mode

# HTTP transport for testing
mcp-kernel-server --http --port 8080

# List available tools
mcp-kernel-server --list-tools

# List available prompts
mcp-kernel-server --list-prompts

Python Integration

from mcp import ClientSession

async with ClientSession() as session:
    await session.connect("http://localhost:8080")
    
    # Verify code safety
    result = await session.call_tool("verify_code_safety", {
        "code": "import os; os.system('rm -rf /')",
        "language": "python"
    })
    print(result["safe"])  # False
    
    # Multi-model code review
    result = await session.call_tool("cmvk_review", {
        "code": "...",
        "focus": ["security", "bugs"]
    })

Part of Agent OS

This MCP server is part of the Agent OS ecosystem:

• Kernel-level safety - Not just prompts, real enforcement
• POSIX-style signals - SIGKILL, SIGSTOP, SIGCONT for agents
• Cross-model verification - Consensus across GPT-4, Claude, Gemini
• Zero violations - Deterministic policy enforcement

License

MIT