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

Annotations already establish that this tool is read-only, idempotent, and non-destructive. The description adds that it aggregates events and both scheduled and unscheduled tasks, but it leaves ambiguous how 'unscheduled tasks' map to a specific date and what happens when the optional date is omitted.

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, front-loaded with the tool's content and followed by practical scheduling guidance. Every word earns its place 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 one-parameter read-only tool this is nearly adequate, but there is no output schema and the description only provides a high-level return summary. It does not clarify the date format, optional date behavior, or how unscheduled tasks are represented, leaving an agent to infer these important operational details.

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, 'date', with no schema description and 0% schema description coverage. The description only repeats 'for a date' and does not specify the expected date format, optionality, or default behavior, so it fails to compensate for the schema's silence.

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 clearly states the resource ('calendar') and its content ('events + scheduled/unscheduled tasks') for a date. It is specific enough to distinguish from task-only siblings like get_tasks, though it does not explicitly name a sibling alternative.

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?

'Check before scheduling' provides an explicit when-to-use directive, and the aggregate listing of events and tasks is the right context for scheduling decisions. It stops short of 5 because it does not mention when not to use it or name an alternative.

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