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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so safety is covered. The description adds genuine behavioral context beyond that: the return format (ISO instants) and that each slot carries call length and host time zone. This is helpful, though it doesn't disclose rate limits or slot-window boundaries.

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 tight sentences with no filler, front-loaded with what the tool returns and immediately followed by the required next action. Every clause earns its place.

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?

With an output schema present and annotations covering the safety profile, the description supplies just the integration detail an agent needs (which tool consumes the output and under what field). Nothing call-critical is missing.

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 limit and time_zone are already documented in the schema. The description adds no parameter detail (e.g. that time_zone affects only display, or that limit caps results soonest-first), so the baseline 3 is appropriate.

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?

It states a specific resource and output ('call times INITE's calendar has free, as ISO instants, with the call length and the host's time zone'), and distinguishes itself from siblings by naming inite_book_call as the consumer. An agent immediately knows this returns bookable slots rather than booking them.

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?

It gives explicit downstream usage: 'Pass one of them to inite_book_call as starts_at.' That is a clear workflow instruction. It does not state when NOT to use the tool or alternatives for listing slots, so it stops short of a 5.

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