start_migration
Start migrating emails from a source IMAP server to a TrekMail mailbox. This is a long-running operation. Both TREKMAIL_ALLOW_MIGRATION=true and confirm_start=true are required.
This record as markdown: /tools/trekmail-mcp-server/start-migration.md
What start_migration does on TrekMail MCP Server
AI agents invoke start_migration to trigger actions in TrekMail MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why start_migration is rated High
This tool triggers a complex, multi-step external operation (IMAP migration) whose outcomes depend on provided arguments and cannot be trivially reversed mid-execution. While not immediately destructive or financial, it executes code/operations against external systems and infrastructure.
From the tool's definition Tool description states 'Start migrating emails from a source IMAP server to a TrekMail mailbox' and explicitly notes 'This is a long-running operation' with required confirmation flags (TREKMAIL_ALLOW_MIGRATION=true and confirm_start=true).
Attacks that exploit this kind of access
The rule that runs start_migration 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 start_migration, this is the rule to start with:
start_migration stays usable, but rate-capped: a runaway agent can't fire it dozens of times 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 start_migration call is checked against it from then on.
Questions about start_migration
Start migrating emails from a source IMAP server to a TrekMail mailbox. This is a long-running operation. Both TREKMAIL_ALLOW_MIGRATION=true and confirm_start=true are required. It is categorised as a Execute tool in the TrekMail MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the TrekMail MCP Server MCP server in PolicyLayer and add a rule for start_migration: 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.
start_migration is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the start_migration 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 start_migration. 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.
start_migration 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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