get_calendar_busy_times

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

With no annotations provided, the description carries full burden. It warns about a required parameter failing, which adds value. However, it doesn't disclose whether this is a read-only operation, what format the busy times return, or any rate limits. The behavioral disclosure is minimal.

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?

The description is only two sentences long and gets straight to the point, the second sentence provides critical usage guidance. However, 'calendars_to_load' is misspelled (missing 'd' in 'loaded') which is a minor distraction but not detrimental.

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?

Given that the tool has a rich input schema (100% coverage) and an output schema, the description doesn't need to explain return values. The description adequately covers the mandatory parameter constraint. The main gap is around when to choose this tool versus 'get_available_slots', which is partially covered by the name difference.

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 100%, so baseline is 3. The description adds a crucial warning about 'calendars_to_load' being required, which goes beyond the schema's basic description. For the other three params, it adds no additional meaning beyond what the schema already provides.

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?

Description states 'Get busy time ranges across connected calendars' which is a clear verb+resource. However, it doesn't explicitly distinguish it from sibling tools like 'get_available_slots'; the purpose is clear but differentiation is implied rather than stated.

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?

The description includes a strong directive that 'calendars_to_load is REQUIRED' and mentions the API returns 400 without it, which is useful. But it does not explain when to use this vs other booking/calendar tools, nor mention any prerequisites.

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