countdown_calc

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, so the safety profile is covered. The description adds that output is expressed in days and weeks, but does not say how weeks are rounded, whether the direction (until vs since) is auto-detected, or what format the result takes.

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?

One tight sentence with the core scope front-loaded and no filler. It is slightly vague in wording ('until or since') but efficiently sized.

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 simple read-only single-parameter tool this is close to sufficient, but ambiguity remains over whether the response includes both days and weeks, and whether 'until/since' is derived automatically or requires a choice, which an agent needs in order to call it correctly.

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 100% with the YYYY-MM-DD format documented, so the single parameter is fully specified. The description adds only marginal meaning (that the date is the reference point for until/since), which is the baseline 3 case.

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 (calculate) and resource (days/weeks until or since a date), which is enough to distinguish it from generic date arithmetic. It doesn't name a sibling like datetime_date_diff, so an agent must still infer that this is the 'countdown' flavor rather than a raw diff.

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 phrase 'until or since' implies the use case (relative countdown/elapsed), but there is no explicit when-to-use versus datetime_date_diff or datetime_add_to_date, and no guidance about direction detection.

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