set_tokens · AI-Canvas MCP Server MCP: Risk & Policy

WHAT IT DOES

What set_tokens does on AI-Canvas MCP Server

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

WHY IT NEEDS A POLICY

Why set_tokens needs a policy

This tool modifies design tokens reversibly—tokens can be changed, reverted, or updated without permanent destruction. It falls under Write category as it creates or modifies data. Severity is medium because misuse could corrupt design consistency across a document or system, affecting output quality, but changes are typically reversible through version control or checkpoints (like create_checkpoint sibling tool).

From the tool's definition Tool name 'set_tokens' and description 'Set or update design tokens in the document' indicate creation and modification of data (design tokens) within a document.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_tokens Rate-limited

set_tokens 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": {
    "set_tokens": {
      "limits": [
        {
          "counter": "set_tokens_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 AI-Canvas MCP Server, so you can run agents against it safely.

FAQ

Questions about set_tokens

What does the set_tokens tool do? +

Set or update design tokens in the document. It is categorised as a Write tool in the AI-Canvas 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 set_tokens? +

Register the AI-Canvas MCP Server MCP server in PolicyLayer and add a rule for set_tokens: 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 AI-Canvas MCP Server. Nothing to install.

What risk level is set_tokens? +

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

Can I rate-limit set_tokens? +

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

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

set_tokens is provided by the AI-Canvas MCP Server MCP server (laoluojuhai/ai-canvas). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.