post-announcement · Canvas MCP Server MCP: Risk & Policy

WHAT IT DOES

What post-announcement does on Canvas MCP Server

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

WHY IT NEEDS A POLICY

Why post-announcement needs a policy

This tool creates and publishes new announcement content in a course, which is a reversible write operation. It modifies course state by adding communication to students, but the announcement can typically be edited or deleted afterward.

From the tool's definition Tool name 'post-announcement' and description 'Post an announcement to a specific course' indicate creation of new content in Canvas LMS.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

post-announcement Rate-limited

post-announcement 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": {
    "post-announcement": {
      "limits": [
        {
          "counter": "post-announcement_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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Instant setup, no code required.

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

FAQ

Questions about post-announcement

What does the post-announcement tool do? +

Post an announcement to a specific course. It is categorised as a Write tool in the 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 post-announcement? +

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

What risk level is post-announcement? +

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

Can I rate-limit post-announcement? +

Yes. Add a rate_limit block to the post-announcement 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 post-announcement completely? +

Set action: deny in the PolicyLayer policy for post-announcement. 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 post-announcement? +

post-announcement is provided by the Canvas MCP Server MCP server (ranver/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.