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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds the scored-output behavior (0-100) and the cost/10-credit tier, which is useful context, but says nothing about input requirements or result semantics beyond the score. Adequate but not rich.

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 tight sentences lead with the mechanism and immediately give the output range, with group and cost metadata on separate lines. No filler, though the description is short enough that it leaves usage and input gaps unaddressed.

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 the return payload needn't be described, and annotations carry the safety profile. However, for a tool with a nested person1/person2 input object and no usage guidance, the omission of any explanation of how the two dates are consumed leaves the definition only minimally complete.

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 only 50% and the two required parameters (person1.date, person2.date) have no descriptions in either schema or description. Worse, the description frames inputs as 'Tzolkin name + tone' while the schema actually accepts birth dates, which does nothing to clarify parameter meaning; fields and precision are only documented in the 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 verb+resource (pair compatibility) and the computation basis (Tzolkin name + tone alignment plus elemental/directional affinity), plus the output shape (0-100 score). It is clearly a two-person tool, distinguishing it from the single-chart Mayan siblings like tzolkin or haab, though it never names those siblings explicitly.

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 explicit routing to alternatives such as astroway_mayan_full or astroway_mayan_tzolkin. The pair framing implies a relationship scenario, but the agent gets no condition that selects this tool over the other Mayan tools.

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