Get Calendar Feed URL

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true, but the description adds critical context: the URL is a bearer credential that grants full calendar access without authentication and survives token rotation. It also instructs against repeating the URL, which goes beyond what annotations imply.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is only three sentences: the first states the core action, the second explains security implications, and the third provides usage restrictions. Every sentence adds essential information without redundancy, and the most important detail is front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple (no parameters), has an output schema, and the description covers the action, security caveats, and when to call. There's no missing context that would leave an agent confused about invocation or side effects.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters and an empty input schema, so there is nothing for the description to explain. Per the rubric, a 0-parameter tool gets a baseline of 4. The description focuses on purpose and usage instead, which is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Fetch the user's private calendar .ics subscription URL.' It also explains the URL's purpose (to see Canvas deadlines in external calendars), which clearly distinguishes it from sibling tools like whoami or my_courses. No other tool covers calendar feeds.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states when to call: only when the user has explicitly asked for their calendar feed or subscription link. It also provides negative instructions—not during general orientation and not to repeat the URL unless asked—making the usage boundaries unambiguous.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.