create_calendar

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

With no annotations, the description carries the full behavioral burden. It usefully discloses the name-collision failure mode, which the schema does not, but says nothing about permissions/authentication requirements, side effects on existing calendars, or what the call returns. Adequate but thin for a mutation tool with zero annotation coverage.

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?

Two short sentences, zero filler, with the core action front-loaded and the failure condition following. Nothing in the text is redundant or restated from the name.

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 single-parameter creation tool with no output schema and no nested objects, the description covers what it creates and the one error case an agent must anticipate. It stops short of describing the returned handle/identifier for the new calendar, which would be the remaining useful detail.

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 is one parameter and schema description coverage is 100% ('Name of the new calendar'), so the schema already does the parameter work. The description adds no extra constraints on the name (length, uniqueness scope, allowed characters) beyond the failure note, so the baseline 3 applies.

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?

States a specific verb (Create) and a precisely-named resource (a new event calendar in iCloud Calendar). The noun 'calendar' cleanly separates it from create_event, bulk_create_events, and create_reminder_list among the siblings, so an agent can route to it without opening any schema.

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?

Usage is implied by the verb and the domain rather than stated: no explicit when-to-use guidance, no comparison to create_event or bulk_create_events for creating multiple calendars. The precondition 'Fails if a calendar with that name already exists' does give a usable constraint before calling, which lifts it above a bare 2.

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