on_this_day

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

With no annotations, the description carries the full burden of behavioral disclosure, but it only states the type of data returned. It does not mention return structure, ordering, pagination, error conditions, or side effects. The gap between 'for a specific date' and the schema's default-to-today behavior also leaves room for misinterpretation.

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 a single, front-loaded sentence that states the action and the subject without filler. Every word earns its place, making it highly efficient.

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?

The tool is simple (2 optional params, no output schema), and the description covers the main purpose. However, it lacks usage guidance and behavioral transparency, which would help an agent decide when to invoke it and what to expect. The schema fills in parameter details, so the overall picture is minimally complete but leaves gaps.

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?

The input schema already fully documents both parameters (date and timezone) with format and defaults, so the description adds little beyond what the schema provides. The phrase 'for a specific date' aligns with the date parameter but doesn't enrich it. Baseline 3 is appropriate given 100% schema coverage.

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 the tool's verb ('Get'), resource ('Star Trek events, air dates, and birthdays'), and scope ('for a specific date'). It is specific enough to convey the core function, but it does not explicitly differentiate from adjacent sibling tools like get_timeline or list_episodes, which might also involve date-based data.

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: call this when you want events for a given date. However, it provides no explicit guidance on when to prefer this over alternatives, no exclusions, and no mention of whether it works without a date (though the schema says it defaults to today).

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