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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description does add non-schema behavioral context — the Zi Wei Dou Shu group membership and a cost of 5 credits (Tier ½) — which is genuinely useful for call budgeting, but it says nothing about what the computation returns or its input requirements.

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 text is short with no filler and the group/cost tags are front-loadable structured metadata. However, brevity here reflects under-specification rather than economy — a whole sentence of the budget could be spent clarifying what the tool produces.

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 no explanation. But for a chart-derivation tool with six parameters sitting among many near-identical palace siblings, the description omits what is computed, from which chart, and how it differs from astroway_ziwei_twelve_palaces — leaving the agent to guess from the name alone.

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 67%, so the schema documents most of the six parameters (fields, precision, timezone, timezoneOffset) but not date/time formats. The description adds no parameter meaning whatsoever, so it fails to compensate for the undocumented remainder.

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 is a noun-phrase gloss on the palace's meaning ('Marriage partner, romantic union') rather than a statement of what the tool does. It largely restates the name/title 'Spouse Palace (Fuqi)' and provides no verb or operation, and it does nothing to distinguish itself from the ten sibling palace tools (career, wealth, health, etc.).

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 prerequisites, and no mention of alternatives such as astroway_ziwei_chart, astroway_ziwei_full_chart, or astroway_ziwei_twelve_palaces. An agent gets nothing to route on.

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