AI agents call youtube_list_comment_replies to retrieve information from Youtube without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns comment replies without creating, modifying, or deleting any data. It is a straightforward read operation that retrieves existing information from a YouTube channel's comments section. The low severity reflects minimal risk even if misused by an AI agent, as it only accesses data the agent already has permission to view.
From the tool's definition Tool name contains 'list' and description states 'Retrieves a page of replies' — both indicate data retrieval with no modification or side effects.
Attacks that exploit this kind of access
Retrieves a page of replies to a specific top-level comment thread. Args - \. It is categorised as a Read tool in the Youtube MCP Server, which means it retrieves data without modifying state.
Register the Youtube MCP server in PolicyLayer and add a rule for youtube_list_comment_replies: 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.
youtube_list_comment_replies is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the youtube_list_comment_replies 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.
Set action: deny in the PolicyLayer policy for youtube_list_comment_replies. 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.
youtube_list_comment_replies 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.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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