AI agents use mark_as_unread to create or update resources in IMAP MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your IMAP MCP Server environment.
This tool modifies email state by toggling the unread flag, which is a reversible write operation. It does not delete data (not Destructive), execute code (not Execute), move money (not Financial), or retrieve data without side effects (not Read).
From the tool's definition Tool name 'mark_as_unread' and description 'Mark email as unread' indicate a modification operation that changes email metadata (the read/unread status flag).
Documented attack patterns abuse exactly the kind of access mark_as_unread gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and IMAP MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for mark_as_unread:
{
"version": "1",
"default": "deny",
"tools": {
"mark_as_unread": {
"limits": [
{
"counter": "mark_as_unread_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}mark_as_unread 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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Mark email as unread. It is categorised as a Write tool in the IMAP MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the IMAP MCP Server MCP server in PolicyLayer and add a rule for mark_as_unread: 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 IMAP MCP Server. Nothing to install.
mark_as_unread 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 mark_as_unread 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 mark_as_unread. 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.
mark_as_unread is provided by the IMAP MCP Server MCP server (non-dirty/imap-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 16 IMAP MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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16 IMAP MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.