# patch

Patches: pending updates, unattended upgrades, package integrity, kernel audit, CVE lookup

Agent View of the PolicyLayer registry record for `patch`. HTML page: https://policylayer.com/tools/defense/patch

## Facts

- Tool: `patch`
- Server: Defense (`defense-mcp-server`) — https://policylayer.com/tools/defense.md
- Install: `npx -y defense-mcp-server`
- Homepage: git+https://github.com/bottobot/defense-mcp-server.git
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 8 (1 required)
- Recommended policy verdict: Rate-limited

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `cveId` | string | no | CVE ID e.g. CVE-2024-1234 |
| `action` | string | yes | Patch management action |
| `dryRun` | boolean | no | Preview only |
| `maxPackages` | number | no | Maximum packages to check |
| `packageName` | string | no | Package name to check urgency for |
| `changed_only` | boolean | no | Only show changed files |
| `package_name` | string | no | Specific package to check |
| `security_only` | boolean | no | Only show security-relevant updates |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "patch",
    "arguments": {
      "action": "<action>"
    }
  }
}
```

## Why patch is rated Medium

Patching applies security updates to system packages, which is a reversible modification operation (updates can be rolled back). While security-critical and important for hardening, it does not irreversibly destroy data like Destructive operations, nor does it execute arbitrary code (Execute category). The tool's purpose is defensive system maintenance, making it Write rather than Read.

From the tool's own definition: "Tool description indicates 'pending updates, unattended upgrades, package integrity' — these are write operations that modify system software and configurations."

## Use case

AI agents use patch to create or update resources in Defense, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Defense environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Defense:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "patch": {
      "limits": [
        {
          "counter": "patch_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Defense (30)

- `app_harden` — Execute — https://policylayer.com/tools/defense/app-harden.md
- `container_isolation` — Execute — https://policylayer.com/tools/defense/container-isolation.md
- `crypto` — Execute — https://policylayer.com/tools/defense/crypto.md
- `ebpf` — Execute — https://policylayer.com/tools/defense/ebpf.md
- `firewall` — Execute — https://policylayer.com/tools/defense/firewall.md
- `harden_kernel` — Execute — https://policylayer.com/tools/defense/harden-kernel.md
- `honeypot_manage` — Execute — https://policylayer.com/tools/defense/honeypot-manage.md
- `incident_response` — Execute — https://policylayer.com/tools/defense/incident-response.md
- `malware` — Execute — https://policylayer.com/tools/defense/malware.md
- `sudo_session` — Execute — https://policylayer.com/tools/defense/sudo-session.md
- `vuln_manage` — Execute — https://policylayer.com/tools/defense/vuln-manage.md
- `waf_manage` — Execute — https://policylayer.com/tools/defense/waf-manage.md
- `wireless_security` — Execute — https://policylayer.com/tools/defense/wireless-security.md
- `zero_trust` — Execute — https://policylayer.com/tools/defense/zero-trust.md
- `api_security` — Read — https://policylayer.com/tools/defense/api-security.md
- `cloud_security` — Read — https://policylayer.com/tools/defense/cloud-security.md
- `dns_security` — Read — https://policylayer.com/tools/defense/dns-security.md
- `secrets` — Read — https://policylayer.com/tools/defense/secrets.md
- `access_control` — Write — https://policylayer.com/tools/defense/access-control.md
- `backup` — Write — https://policylayer.com/tools/defense/backup.md
- `compliance` — Write — https://policylayer.com/tools/defense/compliance.md
- `container_docker` — Write — https://policylayer.com/tools/defense/container-docker.md
- `defense_mgmt` — Write — https://policylayer.com/tools/defense/defense-mgmt.md
- `harden_host` — Write — https://policylayer.com/tools/defense/harden-host.md
- `integrity` — Write — https://policylayer.com/tools/defense/integrity.md
- `log_management` — Write — https://policylayer.com/tools/defense/log-management.md
- `network_defense` — Write — https://policylayer.com/tools/defense/network-defense.md
- `process_security` — Write — https://policylayer.com/tools/defense/process-security.md
- `supply_chain` — Write — https://policylayer.com/tools/defense/supply-chain.md
- `threat_intel` — Write — https://policylayer.com/tools/defense/threat-intel.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=defense · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/defense