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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds that the computation follows the Pythagorean system and what numbers result, but says nothing about determinism limits (e.g., name normalization, diacritics, invalid dates) beyond what annotations supply.

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 well-formed sentence that front-loads the verb and system, then lists outputs, then inputs. No redundant or filler wording.

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 simple two-parameter, read-only calculation tool with no output schema, the description usefully enumerates the returned numbers, which compensates for the missing output schema. Only the response shape (e.g., whether the numbers come as an object or text) is left unstated.

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 both parameters are already documented in the schema with constraints (maxLength 120, YYYY-MM-DD format). The description only restates the inputs generically, adding no new meaning such as handling of middle names or time zones.

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 names a specific verb (Calculate), the specific system (Pythagorean numerology), and enumerates the outputs produced: life path, expression, soul urge, karmic debt. This clearly separates it from numerology-adjacent siblings such as decode_angel_number, though it does not explicitly name a sibling it differs from.

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 explicit when-to-use or when-not-to-use guidance, and no mention of alternatives like decode_angel_number or plan_my_personal_year. The required inputs (birth name and date) only weakly imply the appropriate context.

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