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

Beyond the read-only annotations, the description outlines the specific scope of the tool (1901–2100) and lists complex outputs like 'yin or yang' and 'Lichun'. This defines the functional boundaries and nature of the data being returned.

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 dense but efficient, using the initial clause to front-load the list of all returned data points. While lengthy, every part of the description serves a unique, informative purpose, making the complexity easy to digest.

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 that the tool calculates many specific, complex attributes (elements, Chinese New Year dates, etc.), the description is exceptionally complete. It provides a full map of what the agent can expect, leaving very little ambiguity for successful invocation.

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?

Although schema coverage is 67%, the description adds significant semantic value by detailing how the 'date' parameter should be interpreted (e.g., the year shift for January and February). This crucial contextual information elevates it beyond mere parameter documentation.

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 resource being analyzed—the Chinese zodiac—and enumerates the specific data points provided, such as animal, element, and sexagenary name. While it doesn't directly reference sibling tools, the highly specific output profile makes its purpose distinct from general calendar tools.

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 tool provides excellent usage guidance by defining two distinct input modes (year vs. date of birth). Crucially, it includes a vital operational rule regarding January and February births belonging to the previous year, which prevents common agent invocation errors.

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