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 fully covered. The description's only added behavioral context is the billing metadata '[Cost: 10 credits (Tier 1)]', which is genuinely useful but does not explain what the computed number means or how it is derived.

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 prose is a single efficient sentence with the core purpose front-loaded, followed by short bracketed metadata lines. No filler or repetition, though the group/cost tags are boilerplate rather than explanatory.

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 return values need no explanation, but with 3 required parameters and only 40% schema coverage the definition should clarify what 'name', 'date' and 'year' each represent. Nothing in the description addresses this, leaving a meaningful gap for a caller constructing the request.

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 only 40% (date, name and year are undocumented in the schema), and the description does not compensate at all. The critical ambiguity between 'date' (presumably a birth date) and 'year' (the target calendar year) is left entirely unresolved.

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 concrete verb and resource ('Calculate the Personal Year number'), scopes it ('for a given calendar year') and adds domain meaning ('the 9-year cycle of personal evolution'). The 'Numerology: Pythagorean system' line does separate it from the chaldean/vedic/kabbalistic personal_year siblings, though much of that differentiation is already carried by the tool name itself.

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 never says when to choose this over the ~70 sibling numerology tools, nor does it name an alternative system. A reader must infer the intended use purely from the tool name and the trailing '[Group: Numerology: Pythagorean]' tag.

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