apply_tags_update · Mochi MCP Server MCP: Risk & Policy

WHAT IT DOES

What apply_tags_update does on Mochi MCP Server

AI agents use apply_tags_update to create or update resources in Mochi MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mochi MCP Server environment.

WHY IT NEEDS A POLICY

Why apply_tags_update needs a policy

This tool modifies existing data (card tags) in a reversible manner. While tags can be re-applied or removed again, the operation itself changes card state. The two-phase commit pattern (preview followed by apply) reduces risk but does not eliminate it.

From the tool's definition Tool description states it applies tag changes after user confirmation, indicating it modifies card metadata. It works with tokens from preview operations (add_tags_preview, remove_tags_preview), showing a write operation on flashcard tags.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

apply_tags_update Rate-limited

apply_tags_update 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "apply_tags_update": {
      "limits": [
        {
          "counter": "apply_tags_update_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Mochi MCP Server, so you can run agents against it safely.

FAQ

Questions about apply_tags_update

What does the apply_tags_update tool do? +

Apply tag changes after user confirms. Use with token from add_tags_preview or remove_tags_preview. It is categorised as a Write tool in the Mochi MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on apply_tags_update? +

Register the Mochi MCP Server MCP server in PolicyLayer and add a rule for apply_tags_update: 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 apply_tags_update? +

apply_tags_update is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit apply_tags_update? +

Yes. Add a rate_limit block to the apply_tags_update 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 apply_tags_update completely? +

Set action: deny in the PolicyLayer policy for apply_tags_update. 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 apply_tags_update? +

apply_tags_update 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.