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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the data source (Wikipedia) and input format, but does not specify output format, pagination, error handling, or whether results are limited to a particular year. It is minimal and leaves significant behavioral uncertainty for a tool with no annotation safety profile.

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, efficient sentence with the key information front-loaded: 'On This Day' followed by a colon and a concise explanation. There is no wasted wording, and it delivers the core purpose immediately.

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 the tool has only one parameter and an output schema exists, the description is reasonably complete for basic invocation. It covers the input format and source, but omits details like whether results are limited to a specific year, potential rate limits, or how 'today' is resolved. These gaps are not critical for a simple date-based query, but they are not filled elsewhere.

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 schema defines a single parameter 'q' with a default of empty string, but provides no description. The description adds meaning by indicating that 'q' represents a date in MM/DD format or 'today' (implying the default). This compensates for the 0% schema coverage, though it could be more explicit that 'q' is the date and what 'today' means (e.g., server timezone).

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 returns historical events from Wikipedia for a specified date (MM/DD or today). The resource (Wikipedia) and the key parameter (date) are identified, distinguishing it from general Wikipedia lookup tools. However, it lacks an explicit verb like 'get' or 'retrieve', so it's slightly less directive.

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?

No explicit guidance on when to use this tool versus alternatives such as 'holidays', 'random_fact', or 'wikipedia'. The only usage hint is the input format ('MM/DD or today'), which is helpful but does not address selection criteria or exclusions. An agent would have to infer its niche.

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