Luck Pillars (Da Yun)

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds genuinely new operational context: the endpoint, the required-input contract, and a cost of 10 credits at Tier 1. It still does not say what the sequence contains or how far it extends, but the credit cost and required-field disclosure are real value beyond the structured fields.

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 content sentences plus a compact bracketed metadata block, with the core meaning front-loaded and no filler. The metadata lines (group, endpoint, required, cost) are dense rather than wasted, though the block format is slightly repetitive for a single call.

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 explained, but with 10 input parameters and 20% coverage the agent is left guessing about count (number of pillars?), time (is a birth time needed for this endpoint at all?), and the solar-time/timezone options. For a 10-credit call with this many knobs, the description is too thin.

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 20% across 10 parameters, so the description must carry most of the burden and it does not. It explains why gender matters (it sets the pillar direction), which is a useful semantic addition beyond the male/female enum, but count, time, dayBoundary, trueSolarTime, longitude and language are unexplained in both places.

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 a specific output (a 10-year luck-pillar sequence) and the method that drives it (direction from gender plus year-stem polarity, per Ziping canon). That is clearly more informative than the title 'Luck Pillars (Da Yun)'. It does not explicitly distinguish itself from close siblings such as astroway_bazi_year_pillar_decade or astroway_bazi_yearly, so it stops short of a 5.

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?

It states the required inputs ('Required: date, gender') but gives no when-to-use guidance and never mentions an alternative or exclusion among the many BaZi sibling tools. The agent must infer that this is the multi-decade forward-looking tool rather than a single-pillar or yearly endpoint.

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