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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds no behavioral context beyond the topic — nothing about how date/gender drive the result, determinism, or any constraints, so it does not earn credit above the annotation baseline.

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?

One front-loaded sentence plus group/cost metadata; no filler. The parenthetical enumeration of the nine life areas is long but carries real information, though the overall text is thin for a 9-parameter tool.

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. But with 9 parameters, 44% schema coverage, required gender/date whose roles are unexplained, and no usage guidance, the definition is not complete enough for confident 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?

Schema description coverage is only 44% across 9 parameters, and the description mentions none of them. Critically, it never explains why 'gender' and 'date' are required (kua number derivation) — a domain-specific semantic an agent cannot recover from the schema, which just lists an enum.

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?

States a specific resource ('Eastern-school Bagua mapping of 9 life areas ... onto compass sectors') and enumerates the nine areas, so an agent knows exactly what is produced. It does not explicitly contrast itself with close siblings such as astroway_chinese_feng_shui_lucky_directions or astroway_chinese_feng_shui_kua, which also deal with sectors/directions.

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 when-to-use statement, no prerequisites, and no alternatives named among the many feng shui siblings (flying_star, kua, annual_stars, lucky_directions). The agent must infer from the name alone whether this is the right tool.

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