Adds a comment anchored to a specific text range in the document. NOTE: Due to Google API limitations, comments created programmatically appear in the
AI agents use addComment to create or update resources in Google Workspace MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Google Workspace MCP Server environment.
The addComment tool creates new comments in Google Docs, which is a reversible write operation. Comments can be deleted, making this a Write rather than Destructive action. Severity is medium because comments on shared documents could be disruptive (spam, misinformation) but the blast radius is limited to comment creation rather than data deletion or financial impact.
From the tool's definition Tool description states 'Adds a comment' - this creates new data (a comment) in a Google Doc, modifying the document's content reversibly.
Documented attack patterns abuse exactly the kind of access addComment gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Google Workspace MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for addComment:
{
"version": "1",
"default": "deny",
"tools": {
"addComment": {
"limits": [
{
"counter": "addcomment_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}addComment 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.
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Adds a comment anchored to a specific text range in the document. NOTE: Due to Google API limitations, comments created programmatically appear in the. It is categorised as a Write tool in the Google Workspace MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Google Workspace MCP Server MCP server in PolicyLayer and add a rule for addComment: 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 Google Workspace MCP Server. Nothing to install.
addComment is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the addComment 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 addComment. 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.
addComment is provided by the Google Workspace MCP Server MCP server (sputnicyoji/google-workspace-mcp-with-script). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Google Workspace MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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72 Google Workspace MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.