Lucky Days

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

Annotations already provide readOnlyHint, destructiveHint, and idempotentHint, covering safety and idempotency. The description adds that the tool returns days of the week, but does not elaborate on format, edge cases, or other behavioral details. This is baseline adequacy.

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 description is very short—one sentence, a group label, and an example—with no filler. The group and example are placed after the main statement, which is acceptable. Every element earns its place.

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?

Given there is no output schema, the description should clarify the format of the returned 'Days of week'. It only says 'Days of week traditionally aligned with the sign' without specifying whether output is a list, textual names, or numeric. The parameters are well-documented in the schema, so that is not a gap. Overall, the description is adequate but leaves some ambiguity about the output.

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 100%, so the schema already documents all parameters. The description adds an example request body that illustrates typical values (e.g., timezoneOffset, lat/long), which provides practical context beyond the schema. This meets the baseline expectation but does not significantly enhance understanding.

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 'Days of week traditionally aligned with the sign' combined with the group '[Group: Pet Astrology]' clearly indicates it returns lucky days of the week for a pet based on astrological sign. It distinguishes itself from sibling tools like 'financial_lucky_day' through the group context, but could be more explicit about the pet scope.

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?

No guidance is provided on when to use this tool versus alternatives or when not to use it. The group and title imply pet astrology usage, but there is no explicit instruction about preferred scenarios.

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