calendar_get_freebusy

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

No annotations are provided, so the description carries full burden for behavioral disclosure. It mentions return format (list of busy periods) but does not explicitly state it is a read-only operation, discuss required permissions, idempotency, or rate limits. This is a significant gap for a tool that queries calendar data.

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 concise with 5 lines, front-loading the purpose. Every sentence adds value. The args format is clear, though the structure could be slightly improved with consistent bullet style.

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 3 required parameters, no annotations, but an existing output schema, the description is reasonably complete. It explains return values (list of busy periods) but lacks details on pagination, max time range, or error conditions. For a simple query tool, it meets minimum viability.

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%, so the description must compensate. It adds meaning for all three parameters: calendar_id as 'Calendar name or URL path', start and end with ISO 8601 format examples. This provides essential guidance beyond the schema's minimal type info.

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 it gets busy time slots from a calendar within a time range. It distinguishes from siblings like calendar_find_available_slots by specifying 'busy' instead of 'free'. The verb 'get' and resource 'busy time slots' are specific and 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?

The description explicitly says 'Use this to check for scheduling conflicts before creating events.' This provides clear context for when to use. However, it does not mention when not to use or directly compare with alternatives like calendar_find_available_slots.

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