[CUSTOM] Calls the Marketo REST API directly (not Adobe's native MCP).
AI agents call custom_preview_email to retrieve information from Marketo MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The name 'custom_preview_email' suggests it retrieves a preview/rendering of an email, which is a read operation. However, the description is uninformative ('Calls the Marketo REST API directly') and the 'CUSTOM' prefix with direct API access raises uncertainty — it could execute arbitrary API calls. Confidence is low due to the vague description.
From the tool's definition Tool name includes 'preview_email', suggesting a read/display operation. Description only states it 'Calls the Marketo REST API directly' with no further detail about what the call does.
Attacks that exploit this kind of access
[CUSTOM] Calls the Marketo REST API directly (not Adobe's native MCP). It is categorised as a Read tool in the Marketo MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Marketo MCP Server MCP server in PolicyLayer and add a rule for custom_preview_email: 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 Marketo MCP Server. Nothing to install.
custom_preview_email is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the custom_preview_email 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 custom_preview_email. 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.
custom_preview_email is provided by the Marketo MCP Server MCP server (tyron-pretorius/marketo-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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