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

Annotations already declare readOnlyHint, idempotentHint and non-destructive safety. Beyond that the description adds a non-obvious methodological fact (month branch resolved via mid-month jieqi) and the cost of 10 credits at Tier 1, which materially affects invocation. It does not cover auth or response shape, but the output schema exists so that is less critical.

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 purpose sentence is front-loaded, followed by compact bracketed metadata for group, endpoint, required params and cost. Every element earns its place with no redundancy.

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?

For a 12-parameter tool the definition gives purpose, endpoint, required inputs and cost, and an output schema exists to cover return values. However, the low parameter coverage means an agent is left without guidance on timezone, dayBoundary, trueSolarTime or natalTzOffset, which are the semantically tricky inputs here.

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 33% (four of twelve params documented), so the description carries the burden of compensating for the undocumented parameters, but it does not. It merely restates the three required parameters already declared in the schema's required list, adding no syntax, format, or interaction semantics.

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 analytical technique (Sheng-Ke + branch-clash) and the scope that differentiates it (a specific calendar month, resolved via mid-month jieqi). It anchors itself to astroway_bazi_yearly, so an agent can tell it apart from the year-scoped sibling. The only weakness is that it is defined relatively to the yearly tool rather than standing on its own.

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?

The month scope implies when this tool is appropriate versus a yearly or daily forecast, but usage is only implicit. There are no explicit when/when-not statements and no routing to alternative BaZi forecasting siblings. Adequate but leaves the agent to infer selection.

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