[CUSTOM] Calls the Marketo REST API directly (not Adobe's native MCP).
AI agents call custom_describe_custom_activity_type 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 tool name contains 'describe' which typically indicates a read/metadata retrieval operation. However, the description is largely uninformative ('Calls the Marketo REST API directly') and does not specify what the tool actually does beyond making an API call.
From the tool's definition 'describe_custom_activity_type' suggests fetching metadata/schema about a custom activity type, similar to a describe/get operation
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_describe_custom_activity_type: 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_describe_custom_activity_type 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_describe_custom_activity_type 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_describe_custom_activity_type. 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_describe_custom_activity_type 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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