Mark MailPlus messages as read, unread, flagged, or unflagged.
AI agents use mailplus_mark_messages to create or update resources in Synology Office — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Synology Office environment.
Marking messages as read/unread or flagged/unflagged are Write operations—they modify message attributes reversibly without permanent data loss or code execution. The action is non-destructive and localized to message flags/read-state. Severity is low because misuse would only affect message organization and notification state, with no cascading impacts on system integrity or data loss.
From the tool's definition Tool description states it 'Mark MailPlus messages as read, unread, flagged, or unflagged.' These are reversible state changes to message metadata that do not delete, execute code, or create financial obligations.
Documented attack patterns abuse exactly the kind of access mailplus_mark_messages gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Synology Office, and nothing reaches the server without passing your rules. This is the rule we recommend for mailplus_mark_messages:
{
"version": "1",
"default": "deny",
"tools": {
"mailplus_mark_messages": {
"limits": [
{
"counter": "mailplus_mark_messages_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}mailplus_mark_messages 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.
Free to start. No card required.
Mark MailPlus messages as read, unread, flagged, or unflagged. It is categorised as a Write tool in the Synology Office MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Synology Office MCP server in PolicyLayer and add a rule for mailplus_mark_messages: 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 Synology Office. Nothing to install.
mailplus_mark_messages 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 mailplus_mark_messages 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 mailplus_mark_messages. 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.
mailplus_mark_messages is provided by the Synology Office MCP server (vocweb/synology-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Synology Office, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
39 Synology Office tools catalogued and risk-classified — across an index of 43,000+ MCP servers.