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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful context not in annotations: the exact output scope (lunar month/day, leap-month flag, Chinese New Year) and the cost line (10 credits, Tier 1), which informs budgeting. It does not discuss edge cases such as what happens near a day boundary or in a non-China timezone.

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?

One front-loaded sentence that names the conversion and the two value-adds, followed by compact bracketed metadata. No filler sentences; the metadata block is boilerplate but terse and useful for cost/endpoint discovery.

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-value shape need not be explained, and the description does sketch its scope. What is missing is how the optional temporal parameters affect the answer — whether the lunar day is derived from the supplied `time`/`timezone`/`timezoneOffset` — which is the one thing an agent cannot get from the schema 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 a middling 57%, and the description contributes nothing beyond the schema: it repeats only that `date` is required. The six optional parameters (time, timezone, timezoneOffset, precision, fields, language) get no mention, and for a calendar-conversion tool the timezone assumption materially changes the result, so that silence is a real gap.

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?

States a specific verb+resource: converts a Gregorian date to its Chinese lunar month and day, plus leap-month detection and that year's Chinese New Year. This is clearly distinct from most siblings (e.g. bazi chart builders, tong shu). However it never names the closest relatives (astroway_calendar_lunar_calendar, astroway_chinese_solar_terms), so the agent must infer the boundary itself.

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 or when-not-to-use guidance and no alternative tool is named. The only usage signal is the bracketed [Required: date], which is a schema restatement rather than routing advice. An agent could easily confuse this with astroway_calendar_lunar_calendar.

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