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 does add two genuinely useful behavioral facts — that the label is not unique beyond the 52-year cycle and that the call costs 10 credits (Tier 1) — but says nothing about the returned structure or the assumed calendar.

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 core semantics are front-loaded into a single tight sentence, with group/cost metadata relegated to bracketed tags. Nothing is wasted, though the tags are structured metadata rather than description prose.

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, and the annotations cover the safety profile. What is still missing is the calendar assumed by the 'date' input (Gregorian vs. other) and any indication of when to prefer this over the standalone tzolkin/haab tools.

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%; the two optional params (fields, precision) are fully documented in the schema, while 'date' is only constrained by a pattern. The description adds no parameter meaning at all, so this sits at the baseline for a mostly-covered schema.

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 computed artifact — a combined Tzolkin + Haab date label — and its scope (unique within the 52-year / 18,980-day cycle). The word 'Combined' implicitly sets it apart from the sibling astroway_mayan_tzolkin and astroway_mayan_haab tools, though it never names them directly.

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 statement, no prerequisites, and no explicit routing to or away from the individual tzolkin/haab siblings. The only hint is the adjective 'Combined', which is too thin to count as guidance.

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