# 1. Install the plugin (adds hooks + skill to your project)
claude plugin install wshobson/agents/protect-mcp

# 2. Configure hooks in .claude/settings.json (see below)

# 3. Start the receipt-signing server (runs locally, no external calls)
npx protect-mcp@latest serve --enforce

# 4. Use Claude Code normally. Every tool call is now policy-evaluated
#    and produces a signed receipt in ./receipts/

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": ".*",
        "hook": {
          "type": "command",
          "command": "npx protect-mcp@latest evaluate --policy ./protect.cedar --tool \"$TOOL_NAME\" --input \"$TOOL_INPUT\" || exit 2"
        }
      }
    ],
    "PostToolUse": [
      {
        "matcher": ".*",
        "hook": {
          "type": "command",
          "command": "npx protect-mcp@latest sign --tool \"$TOOL_NAME\" --input \"$TOOL_INPUT\" --output \"$TOOL_OUTPUT\" --receipts ./receipts/"
        }
      }
    ]
  }
}

// Allow read-only tools by default
permit (
    principal,
    action in [Action::"Read", Action::"Glob", Action::"Grep", Action::"WebFetch"],
    resource
);

// Require explicit allow for destructive tools
permit (
    principal,
    action == Action::"Bash",
    resource
) when {
    // Allow safe commands only
    context.command_pattern in ["git", "npm", "ls", "cat", "echo", "pwd", "test"]
};

// Never allow recursive deletion
forbid (
    principal,
    action == Action::"Bash",
    resource
) when {
    context.command_pattern == "rm -rf"
};

// Require confirmation for writes outside the project
forbid (
    principal,
    action in [Action::"Edit", Action::"Write"],
    resource
) when {
    context.path_starts_with != "."
};

npx @veritasacta/verify receipts/2026-04-15T10-30-00Z.json
# Exit 0 = valid
# Exit 1 = tampered
# Exit 2 = malformed

npx @veritasacta/verify receipts/*.json

/verify-receipt receipts/latest.json
/audit-chain ./receipts/ --last 20

{
  "receipt_id": "rec_8f92a3b1",
  "receipt_version": "1.0",
  "issuer_id": "claude-code-protect-mcp",
  "event_time": "2026-04-15T10:30:00.000Z",
  "tool_name": "Bash",
  "input_hash": "sha256:a3f8...",
  "decision": "allow",
  "policy_id": "autoresearch-safe",
  "policy_digest": "sha256:b7e2...",
  "parent_receipt_id": "rec_3d1ab7c2",
  "public_key": "4437ca56815c0516...",
  "signature": "4cde814b7889e987..."
}