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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely new operational facts not in annotations: endpoint (POST /v1/mayan/long-count) and cost (10 credits, Tier 1), which an agent needs for budgeting. It adds nothing about output shape, but an output schema exists.

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?

Very compact and front-loaded: the notation/epoch explanation comes first, followed by clean bracketed metadata tags. Almost every line is scannable, though the notation sentence describes the return value more than the action.

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?

With an output schema and full annotations, the description need not cover return values or safety, and it does supply endpoint, cost, and the required parameter. The missing piece for a tool sitting among eight Mayan siblings is any indication of when to pick this one over the others.

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%: `fields` and `precision` are documented inline with examples, while the required `date` has only a regex pattern and no prose. The description's '[Required: date]' adds no meaning beyond the schema. Nothing here explains the date format or semantics beyond the pattern.

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 explains what a Long Count is (five-place baktun.katun.tun.uinal.kin notation, days since 4 Ahau 8 Cumku) and the group/endpoint tags signal it computes a Mayan calendar value for a date. However, no verb is stated and it never distinguishes itself from the many Mayan siblings (tzolkin, haab, calendar_round, full), so an agent must infer the operation.

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 and no exclusions. The only routing aid is '[Required: date]', which merely restates the schema's required field and does not help choose between this and astroway_mayan_tzolkin, haab, or calendar_round.

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