Reply to an existing email message
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Part of the Gmail Osiris server.
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AI agents use send_email_reply to create or modify resources in Gmail Osiris. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call send_email_reply repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Gmail Osiris.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"send_email_reply": {
"limits": [
{
"counter": "send_email_reply_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Gmail Osiris policy for all 12 tools.
These attack patterns abuse exactly the kind of access send_email_reply gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Reply to an existing email message. It is categorised as a Write tool in the Gmail Osiris MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Gmail Osiris MCP server in PolicyLayer and add a rule for send_email_reply: 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 Gmail Osiris. Nothing to install.
send_email_reply 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 send_email_reply 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 send_email_reply. 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.
send_email_reply is provided by the Gmail Osiris MCP server (sk1122/gmail-osiris). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 12 Gmail Osiris tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.