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

Annotations declare readOnlyHint=true and destructiveHint=false, so the safety profile is already conveyed. The description adds useful behavioral specifics: deterministic ordering, the inclusion of historical orthography, Kʼicheʼ names, glosses, and scheme-dependent direction/colour values. It does not go into pagination behavior, but the annotations plus schema cover the key operational expectations.

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?

A single dense sentence that front-loads the core action and resource, then efficiently lists return contents and intended use cases. Every clause adds information — no filler, no repetition of schema details, and the use-case closing sentence 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 no output schema, the description reasonably compensates by enumerating what each returned entry contains and the ordering guarantee. Pagination and language fallback behavior are left to the schema, which documents them fully. The only mild gap is not explicitly routing the agent away from the single-sign sibling, but the 'whole set' wording largely covers that.

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 fully documents all five parameters, including enum meanings, defaults, compact-shape behavior, and ranges. The description references the 'requested scheme' for direction/colour, but adds no semantic detail beyond the schema's own thorough parameter descriptions. Baseline 3 applies.

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 ('Retrieve'), a precise resource ('all twenty Tzolkin day signs'), and an ordering guarantee ('in sequence order from Imix to Ajaw'). This clearly differentiates it from sibling tools like the single-sign ID endpoint or the daily/monthly tools.

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?

Offers explicit use cases ('nawal pickers, sign reference pages') and frames the tool as serving 'the whole set in one call.' It does not name sibling alternatives explicitly or state when not to use it, but the intended usage context is clear.

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