List Calendars

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely new behavior: a disabled calendar lists nothing and blocks createEvent/createTask until the user enables it, which is a downstream consequence the agent could not infer from any structured field.

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 short sentences with zero filler: the field list first, then the id's downstream use, then the disabled-calendar caveat. The most actionable information (the id) is front and center.

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, so the description carries the burden of describing return values, and it does so by naming every field. Combined with the explanation of what 'disabled' means operationally, an agent has everything needed to call this and use the result correctly.

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 takes no parameters, so the baseline is 4 and there is no parameter surface the description needed to explain. Instead it spends its words on output-field meaning, which is the useful place for them.

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 and resource ('List calendars') and immediately enumerates the returned fields (id, name, readOnly, disabled, supportsEvents, supportsTasks), so the agent knows exactly what it gets. No sibling tool lists calendars, but the description also cross-references the event/task tools that consume the id, making its role unambiguous.

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?

Implies the primary use case explicitly: 'The id is the calendarId of the event and task tools,' which tells the agent to call this before createEvent/createTask. It also names the precondition that a disabled calendar causes createEvent/createTask to refuse. It stops short of an explicit when-not-to-use statement, but no competing calendar-listing alternative exists.

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