set_domain_smtp
Set how a domain sends outbound mail:
This record as markdown: /tools/trekmail-mcp-server/set-domain-smtp.md
What set_domain_smtp does on TrekMail MCP Server
AI agents use set_domain_smtp to create or update resources in TrekMail MCP Server, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your TrekMail MCP Server environment.
Why set_domain_smtp is rated Medium
This tool creates or modifies SMTP settings for outbound mail delivery, making it a Write action. While not directly moving money, misconfiguration could severely impact email operations and deliverability across an entire domain. Severity is high due to the blast radius (affects all outbound mail from a domain), though the action is reversible if corrected.
From the tool's definition Tool description states 'Set how a domain sends outbound mail' — this modifies email infrastructure configuration (SMTP settings) for a domain, which is a reversible configuration change.
Attacks that exploit this kind of access
The rule that runs set_domain_smtp safely
PolicyLayer is an MCP gateway: it sits between your AI agents and TrekMail MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For set_domain_smtp, this is the rule to start with:
set_domain_smtp 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.
The button opens the PolicyLayer dashboard: create your workspace, connect TrekMail MCP Server, apply this rule, and every set_domain_smtp call is checked against it from then on.
Questions about set_domain_smtp
Set how a domain sends outbound mail:. It is categorised as a Write tool in the TrekMail MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the TrekMail MCP Server MCP server in PolicyLayer and add a rule for set_domain_smtp: 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 TrekMail MCP Server. Nothing to install.
set_domain_smtp 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 set_domain_smtp 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 set_domain_smtp. 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.
set_domain_smtp is provided by the TrekMail MCP Server MCP server (trekmail/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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