Get Calendar Feed URL

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

Beyond the annotations (readOnly, openWorld, idempotent), the description discloses critical security behavior: the URL is a bearer credential, grants full calendar access without authentication, and survives token rotation. It also advises caution about repeating the URL, adding real behavioral context.

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?

Three sentences, front-loaded with the core purpose, followed by a security warning and usage constraints. Every sentence serves a purpose with no filler or redundancy.

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?

For a zero-parameter tool with an output schema, the description is complete: it explains what is returned (the URL), its security implications, and when to use it. The output schema likely describes the URL format, while the description covers the important caveats.

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?

There are zero parameters, so the baseline is 4. The description adds no parameter details because there are none; the schema is fully trivially covered. It doesn't need to compensate for any gaps.

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 uses a specific verb ('Fetch') and resource ('user's private calendar .ics subscription URL'), and explains its purpose as a subscription link for Google/Apple/Outlook to see Canvas deadlines. It clearly distinguishes from siblings like get_syllabus or course_content by focusing on the calendar feed URL.

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?

Explicitly states when to call (only when user explicitly asks for calendar feed/subscription link) and when not to (not during general orientation), plus not to repeat the URL unless asked. This provides clear usage boundaries without needing alternative tool mentions.

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