destructive_command_guard 0.4.3

A Claude Code hook that blocks destructive commands before they execute
Documentation 
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{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://github.com/Dicklesworthstone/destructive_command_guard/docs/json-schema/hook-output.json",
  "title": "DCG Hook Output",
  "description": "JSON output format for dcg when used as a Claude Code PreToolUse hook. Only emitted when a command is denied; allowed commands produce no output.",
  "type": "object",
  "required": ["hookSpecificOutput"],
  "properties": {
    "hookSpecificOutput": {
      "type": "object",
      "description": "The hook-specific output payload for Claude Code",
      "required": ["hookEventName", "permissionDecision", "permissionDecisionReason"],
      "properties": {
        "hookEventName": {
          "type": "string",
          "const": "PreToolUse",
          "description": "The hook event type, always 'PreToolUse' for dcg"
        },
        "permissionDecision": {
          "type": "string",
          "enum": ["allow", "deny"],
          "description": "The permission decision: 'deny' blocks the command, 'allow' permits it"
        },
        "permissionDecisionReason": {
          "type": "string",
          "description": "Human-readable explanation of why the command was blocked, including the rule ID, reason, and remediation instructions"
        },
        "allowOnceCode": {
          "type": "string",
          "description": "Short alphanumeric code for one-time bypass via 'dcg allow-once <code>'",
          "pattern": "^[a-f0-9]{6}$"
        },
        "allowOnceFullHash": {
          "type": "string",
          "description": "Full SHA-256 hash of the command for verification, prefixed with 'sha256:'",
          "pattern": "^sha256:[a-f0-9]{64}$"
        },
        "ruleId": {
          "type": "string",
          "description": "Stable pattern identifier in format 'pack.category:pattern-name' for allowlisting",
          "examples": ["core.git:reset-hard", "core.filesystem:rm-rf-root"]
        },
        "packId": {
          "type": "string",
          "description": "The security pack that matched, in format 'category.name'",
          "examples": ["core.git", "core.filesystem", "database.postgresql"]
        },
        "severity": {
          "type": "string",
          "enum": ["critical", "high", "medium", "low"],
          "description": "Severity level of the blocked command"
        },
        "confidence": {
          "type": "number",
          "minimum": 0.0,
          "maximum": 1.0,
          "description": "Match confidence score from 0.0 to 1.0"
        },
        "remediation": {
          "type": "object",
          "description": "Suggested remediation for the blocked command",
          "required": ["explanation", "allowOnceCommand"],
          "properties": {
            "safeAlternative": {
              "type": "string",
              "description": "A safer alternative command that achieves similar results"
            },
            "explanation": {
              "type": "string",
              "description": "Explanation of why the alternative is safer or what the user should do"
            },
            "allowOnceCommand": {
              "type": "string",
              "description": "The full 'dcg allow-once <code>' command for one-time bypass"
            }
          }
        }
      }
    }
  },
  "examples": [
    {
      "hookSpecificOutput": {
        "hookEventName": "PreToolUse",
        "permissionDecision": "deny",
        "permissionDecisionReason": "BLOCKED by dcg\n\nTip: dcg explain \"git reset --hard HEAD~5\"\n\nReason: git reset --hard destroys uncommitted changes\n\nRule: core.git:reset-hard\n\nCommand: git reset --hard HEAD~5",
        "ruleId": "core.git:reset-hard",
        "packId": "core.git",
        "severity": "critical",
        "confidence": 0.95,
        "allowOnceCode": "a1b2c3",
        "allowOnceFullHash": "sha256:abc123def456abc123def456abc123def456abc123def456abc123def456abc1",
        "remediation": {
          "safeAlternative": "git stash",
          "explanation": "Use git stash to save your changes before resetting.",
          "allowOnceCommand": "dcg allow-once a1b2c3"
        }
      }
    }
  ]
}