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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety and side-effect behavior. The description adds valuable context beyond these: 'No generative AI is used' and 'Use only with the subject’s permission', which inform the agent of privacy and non-generative nature. This enriches the description without contradicting annotations.

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 description is front-loaded with the primary usage condition ('Use this when...') and states exclusions and key behavioral notes in subsequent sentences. It is bilingual, repeating content in Chinese, which doubles length but is appropriate for a localized tool. Each English sentence earns its place, though the repetition slightly reduces conciseness.

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?

Given the output schema, 100% parameter coverage, and annotations, the description adequately covers when to use, exclusions, permissions, and the output nature. It doesn't mention error handling or edge cases, but these are less critical given the structured schema and clear prerequisites. The description is sufficient for an agent to call the tool correctly.

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 100%, so every parameter (birth_date, birth_time, latitude, longitude, timezone, reading_date, locale) already has detailed documentation. The description's mention of 'complete birth inputs' reinforces the requirement but adds no additional semantic meaning beyond the schema. Baseline 3 is appropriate since the schema carries the full burden.

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 clearly states the tool's purpose: providing personalized daily Bazi guidance for a specific reading date when complete birth inputs are supplied. It explicitly contrasts with a 'date-only almanac request', distinguishing it from the sibling get_daily_almanac. The verb 'returns' and resource 'chart and daily guidance' make the function unambiguous.

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 description explicitly states when to use the tool ('when the user wants personalized daily Bazi interactions... and has supplied the complete birth inputs') and when not to use it ('Do not use this for a date-only almanac request or when any birth input is missing'). It also adds a permission requirement, giving clear conditions and exclusions without ambiguity.

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