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

Annotations already declare this a read-only, idempotent, non-destructive, closed-world operation, so safety is fully covered. The description adds the cost tier (10 credits) and the shape of the returned values, but since an output schema exists the return enumeration is largely redundant and it discloses nothing about the date-range validity or error behavior.

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?

Two compact lines with the core purpose front-loaded, followed by structured group and cost tags. No filler sentences and nothing that needs trimming.

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 simple date-driven lookup with an output schema present, the description covers the essentials of what it returns and its cost. It is thin on disambiguation from the other Mayan tools and says nothing about the accepted date range, leaving gaps an agent would have to guess at.

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%: fields and precision are documented in-schema, while date carries only a regex pattern. The description adds nothing about any parameter, and the date format is self-evident from the pattern, so this is baseline adequate rather than additive.

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 resource (the 260-day sacred calendar) and enumerates exactly what it returns (1-13 number, 20 day-name, element, direction, keyword), which is more precise than the title. However, it never distinguishes itself from close siblings like astroway_mayan_haab, astroway_mayan_long_count, astroway_mayan_lord_of_night, or astroway_mayan_full, so an agent cannot tell which Mayan component to pick.

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 statement of what inputs it needs (a date), and no mention of when to prefer it over astroway_mayan_full or astroway_mayan_calendar_round. The only implied usage is 'give a date'.

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