Send a message to a guest in a Guesty conversation.
Part of the Guesty server.
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AI agents use send_guest_message to create or modify resources in Guesty. 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_guest_message 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 Guesty.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"send_guest_message": {
"limits": [
{
"counter": "send_guest_message_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Guesty policy for all 43 tools.
These attack patterns abuse exactly the kind of access send_guest_message 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.
Send a message to a guest in a Guesty conversation.. It is categorised as a Write tool in the Guesty MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Guesty MCP server in PolicyLayer and add a rule for send_guest_message: 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 Guesty. Nothing to install.
send_guest_message 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_guest_message 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_guest_message. 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_guest_message is provided by the Guesty MCP server (guesty-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 43 Guesty tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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