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

Annotations already mark the operation as read-only, and the description adds rich behavioral content: both naming traditions, glosses, direction/colour under the requested scheme, a keynote, strengths, costs, and guidance. It does not describe the exact response shape, but no output schema exists and the listed contents give a strong expectation of what the tool returns.

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 dense sentences with the action and resource front-loaded. The long content list is not padding; each item helps shape expected output. No wasted words.

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?

For a read-only single-item lookup, the description covers the resource, use case, and returned content domains. The schema already handles language fallback, compact shape, and directionScheme details, while annotations cover the safety profile, so the description is sufficiently 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 description coverage is 100%, so the baseline is 3. The description adds mild meaning by tying 'under the requested scheme' to directionScheme and 'one... sign' to id, but lang and compact are only explained 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?

The description uses a specific verb ('Retrieve the full profile') and names the resource ('one Tzolkin day sign') with an explicit content list. It clearly distinguishes this per-id tool from the sibling list endpoint by emphasizing a single sign.

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?

The description states it is built for nawal detail pages, sign cards, and chatbot answers about a single Mayan sign, giving clear context for when to use it. It does not explicitly tell the agent to use the plural day-signs sibling when a list of all signs is needed, so there is no explicit exclusion.

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