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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds genuinely new context — the 5-credit cost/tier and the POST endpoint — which helps an agent gauge expense. It stops short of describing what the palace reading contains beyond the topic words, but with annotations and an output schema present, a 3 is appropriate.

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 semantic line is front-loaded and the bracketed metadata tags are compact and scannable, with no wasted prose. The trade-off is that the brevity is close to under-specification for a chart-producing tool, keeping it out of 5 territory.

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 an output schema present, return values need no explanation, and annotations cover the safety profile, so the description is not required to carry those burdens. Still, it leaves out any guidance on how the palace result is used or how it relates to the wider Zi Wei chart tools, which is a real gap for a 6-parameter reading endpoint.

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 coverage is 67%, with the richer prose reserved for fields, timezone and precision. The only parameter information in the description is '[Required: date]', which merely restates what the schema's required array already declares, so it adds no meaning beyond structured data. Baseline 3 fits a mid-coverage schema carrying most of the load.

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 domain concept (brothers, sisters, peer relationships) and tags the group (Zi Wei Dou Shu) and endpoint, so the topic is identifiable. However, it states no verb+resource action — it never says it computes/returns the Siblings Palace of a Zi Wei chart — so it reads as a topic label rather than a stated purpose. It is not misleading, just under-articulated relative to its many ziwei_palace_* siblings.

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 when-to-use guidance, no mention of when to prefer this over sibling palaces (career, spouse, children) or over the aggregate astroway_ziwei_twelve_palaces / astroway_ziwei_full_chart tools. The [Required: date] and [Cost: 5 credits] lines are operational facts, not usage guidance.

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