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

Goes well beyond the annotations: it discloses the ranking algorithm (everyone in hours, then fewest outside, then least early/late), DST correctness, weekend flagging, and — critically — the commercial behavior of a $0.002 USDC x402 charge per successful call. The annotations already say readOnly/idempotent, so the description adding cost, ranking, and correctness guarantees is exactly the extra value wanted.

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?

Front-loaded with the verb and required input, then the return payload, then pricing/transport. The return-value enumeration is dense and long, and the endpoint URL sits at the tail, but nearly every clause carries information an agent needs.

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 the return shape — and it does, listing windows, ranked slots, per-participant local time and weekday, and UTC offsets. Combined with DST/weekend semantics and payment terms, an agent has everything needed to call and interpret it.

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 coverage is 63%, which sets a baseline of 3. The description reinforces the zones format with a concrete example (Asia/Tokyo@08:00-18:00) and mentions dates and working hours, but leaves 'top', 'step', 'duration', 'workStart' and 'workEnd' entirely to the schema with no added meaning.

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 ('Find the best meeting times across time zones') and immediately defines the inputs (2-20 IANA zones, a date) and the output shape (working-hour windows, ranked slots). It is unmistakable against neighbors like timezone_convert or date_calc, which do conversions rather than multi-party scheduling.

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 implies usage through its input recipe ('give 2-20 IANA zones ... and a date') but never says when to prefer this over alternatives such as timezone_convert, holidays_business_days, or date_calc, nor any when-not-to-use case. It also notes the companion HTTPS endpoint and that it runs offline, which is helpful context but not selection guidance.

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