youtube_update_caption · Youtube MCP: Risk & Policy

WHAT IT DOES

What youtube_update_caption does on Youtube

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

WHY IT NEEDS A POLICY

Why youtube_update_caption needs a policy

This tool modifies existing captions reversibly—the changes can be undone by updating again or restoring from backups. It does not delete data (which would be Destructive) nor execute arbitrary code (Execute). While it affects a public YouTube channel's content, the blast radius is limited to caption metadata for a single video, and the action is reversible.

From the tool's definition Tool name contains 'update' and description states 'Update an existing caption track', indicating modification of existing data. The caption track is metadata associated with a video.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

youtube_update_caption Rate-limited

youtube_update_caption stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "youtube_update_caption": {
      "limits": [
        {
          "counter": "youtube_update_caption_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Youtube, so you can run agents against it safely.

FAQ

Questions about youtube_update_caption

What does the youtube_update_caption tool do? +

Update an existing caption track. It is categorised as a Write tool in the Youtube MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on youtube_update_caption? +

Register the Youtube MCP server in PolicyLayer and add a rule for youtube_update_caption: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Youtube. Nothing to install.

What risk level is youtube_update_caption? +

youtube_update_caption is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit youtube_update_caption? +

Yes. Add a rate_limit block to the youtube_update_caption rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block youtube_update_caption completely? +

Set action: deny in the PolicyLayer policy for youtube_update_caption. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides youtube_update_caption? +

youtube_update_caption is provided by the Youtube MCP server (tuitamogamer-gpt/youtube-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.