AI agents call canvas_get_grades to retrieve information from Canvas without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves grade information from Canvas LMS without modifying, executing, or deleting any data. It is a simple query operation that returns existing grade data. The low severity reflects minimal blast radius—even if an AI agent retrieves grades it shouldn't, no data is changed or destroyed. Confidence is high because the description clearly indicates a retrieval operation with no side effects.
From the tool's definition Tool name 'canvas_get_grades' and description 'all graded assignments in the course plus your overall current grade' indicate data retrieval only. The verb 'get' and the absence of any modification, deletion, or execution language confirm read-only behavior.
Attacks that exploit this kind of access
Without assignment_id: all graded assignments in the course plus your overall current grade. It is categorised as a Read tool in the Canvas MCP Server, which means it retrieves data without modifying state.
Register the Canvas MCP server in PolicyLayer and add a rule for canvas_get_grades: 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. Nothing to install.
canvas_get_grades 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 canvas_get_grades 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 canvas_get_grades. 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.
canvas_get_grades is provided by the Canvas MCP server (tylergibbs1/canvas-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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