List announcements (optionally filtered by course)
AI agents call list_announcements to retrieve information from Canvas MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries announcements, which is a read-only operation. It has no destructive, financial, or execution capabilities. The optional filtering parameter does not change the fundamental nature of the operation—it remains a data retrieval function with minimal blast radius if misused by an AI agent.
From the tool's definition Tool name 'list_announcements' and description 'List announcements (optionally filtered by course)' indicate retrieval of existing data with no modification or side effects.
Documented attack patterns abuse exactly the kind of access list_announcements gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Canvas MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_announcements:
{
"version": "1",
"default": "deny",
"tools": {
"list_announcements": {}
}
}list_announcements is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List announcements (optionally filtered by course). It is categorised as a Read tool in the Canvas MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Canvas MCP Server MCP server in PolicyLayer and add a rule for list_announcements: 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.
list_announcements 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 list_announcements 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 list_announcements. 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.
list_announcements is provided by the Canvas MCP Server MCP server (plyght/canvas-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Canvas MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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30 Canvas MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.