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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds the operational detail of a POST endpoint but nothing about expected return format, error behavior, or side effects. It does not contradict the annotations, but also does not go beyond them in a meaningful way.

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 only two sentences, with the first listing the output components and the second giving the HTTP endpoint. It is front-loaded with the purpose. The mention of the HTTP endpoint, while useful, is a minor extra that could be omitted, but overall it is efficient and does not waste words.

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 tool with six parameters and no output schema, the description does list what the reading includes, which is helpful. However, it does not explain edge cases such as missing time or place, nor does it indicate that it combines all the sub-readings. Given the sibling tools, more guidance on when this is appropriate would improve completeness. The schema covers parameter details, but the description lacks sufficient context for effective selection.

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 covers all six parameters with descriptions, so schema coverage is 100%. The description itself does not add any additional meaning to the parameters—it only lists the output components. It does not clarify how 'time' and 'place' affect the result, or the optional 'agent' field. Given the high schema coverage, a baseline 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 clearly states what the tool produces: 'Sun sign, Chinese animal and element, BaZi day master and pillars, Life Path and the AsterNym identity.' The title also calls it 'a whole reading,' which conveys it is an aggregate. However, it does not explicitly differentiate itself from sibling tools like asternym_bazi or asternym_zodiac; the 'whole' is inferred rather than stated as an alternative to separate readings.

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?

There is no guidance on when to use this tool versus the siblings. The description only says it is 'the same engine as every page on the site' and provides an HTTP endpoint, but does not mention that for a single BaZi or zodiac analysis, one should use the specific sibling tools. An agent is left to infer the distinction from the 'whole' wording, which is not explicit enough.

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