list_calendars

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), yet the description adds real substance: shared collections may appear unexpectedly, names are untrusted labels rather than identity, and no merging by name should occur. These are non-obvious behavioral guardrails that go beyond the annotations.

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 tight sentences with the scoping statement front-loaded and no filler. Each sentence carries distinct information, though the density makes it slightly clipped for a first-time reader.

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?

There is no output schema, and the description does sketch the returned metadata (declared component, owner, timezone), which helps. However, pagination behavior via limit/offset is never explained, leaving a gap for a listing tool.

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?

Schema description coverage is 0% and the description never mentions limit or offset. With two undocumented pagination parameters, the description does nothing to compensate; only the schema's type and numeric bounds convey anything.

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 states a specific verb ('Discover') and resource ('CalDAV collections under the configured account's authenticated principal'), plus the metadata it surfaces (component, owner, timezone). This clearly separates it from mail-oriented siblings like list_mail_folders, though it never names an alternative explicitly.

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?

There is no guidance on when to call this versus its siblings, nor any prerequisite or sequencing advice. The notes about shared collections and iOS visibility are caveats about results, not usage conditions.

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