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

The description adds meaningful behavioral detail beyond the readOnlyHint and destructiveHint annotations: it explains calculation rules, master number preservation, the compound-to-root reduction in Chaldean, and the presence of an agreement flag in the response. It discloses what the call returns and how the systems differ without contradicting the annotations.

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 front-loaded with the core action and purpose, and the additional system explanations earn their place by clarifying what distinguishes the two numerology methods. It is slightly longer than strictly necessary, but the details are relevant and useful for selecting this tool over similar numerology endpoints.

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?

With no output schema, the description does a good job of summarizing what the agent will receive: Pythagorean and Chaldean results, interpretations, and an agreement flag. The input schema fully covers the required 'name' and optional 'lang' and 'compact' parameters, so nothing essential is missing for an agent to make a correct call.

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 description coverage is 100%, and the schema already documents each parameter including the 'name' field and the meaning of 'compact'. The description adds general context about the overall calculation, but it does not add meaningful per-parameter insight beyond what the schema already provides, so the baseline score of 3 is appropriate.

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 states exactly what the tool does: calculate a name number in both Pythagorean and Chaldean systems in a single request. It clearly distinguishes itself from sibling tools by emphasizing that it is 'the only numerology API that returns Pythagorean and Chaldean for a name in a single request.' This gives an agent a precise, non-tautological understanding of the tool's role.

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 clearly signals when this tool is appropriate: when a comparison between the two numerology systems is needed, and it explicitly frames itself as ideal for comparison tools and AI assistants. It does not, however, explicitly name sibling alternatives or spell out when not to use it, such as 'use post_numerology_chaldean if only the Chaldean number is needed.'

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