update_card_preview · Mochi MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_card_preview does on Mochi MCP Server

AI agents call update_card_preview to retrieve information from Mochi MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

WHY IT NEEDS A POLICY

Why update_card_preview needs a policy

This tool only previews/displays a diff of proposed changes without applying them. It is a read/display operation that shows what would change, explicitly designed as the first phase of a two-phase commit pattern. No data is modified.

From the tool's definition Preview changes to a card with diff

Attacks that exploit this kind of access

Questions about update_card_preview

What does the update_card_preview tool do? +

Preview changes to a card with diff. IMPORTANT: After calling this, you MUST show the diff to the user and ask. It is categorised as a Read tool in the Mochi MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on update_card_preview? +

Register the Mochi MCP Server MCP server in PolicyLayer and add a rule for update_card_preview: 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 Mochi MCP Server. Nothing to install.

What risk level is update_card_preview? +

update_card_preview is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit update_card_preview? +

Yes. Add a rate_limit block to the update_card_preview 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.

How do I block update_card_preview completely? +

Set action: deny in the PolicyLayer policy for update_card_preview. 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.

What MCP server provides update_card_preview? +

update_card_preview is provided by the Mochi MCP Server MCP server (nz99/mochi-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.