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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed world, so safety is covered. The description usefully adds that output is order-stable and date-independent, and the cost tier is disclosed – real behavioral context beyond the annotations, though the still-required `date` for a date-invariant result is left unexplained.

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?

Two tight sentences front-load the resource, ordering and invariance claim; the group/cost brackets are compact metadata. Nothing is padded.

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?

An output schema exists, so return values need not be described, and the annotations cover the safety profile. The description is sufficient for a static reference lookup, with the minor unresolved question of why a date is mandatory for a date-invariant result.

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?

With 6 parameters (1 required) and only 67% schema description coverage, the description supplies no parameter meaning at all. Worse, the one param-related claim it makes ('does not vary with the date') sits awkwardly against a schema that hard-requires `date`, leaving the agent unsure why that input must be sent – it does not compensate for the coverage gap.

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 names the exact resource (the 14 main stars of Zi Wei Dou Shu), its ordering (Zi Wei series then Tian Fu series) and the payload it carries (theme/archetype), which is strictly different from the sibling Zi Wei chart/palace/transformation tools. An agent can identify this as a static definitional table without opening the schema.

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?

Calling it a 'Reference table: does not vary with the date' implies the appropriate use (static star lookup rather than a chart computation), but no sibling alternative is named and no when-not condition is given. Usage is inferable rather than stated.

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