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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely useful operational context beyond that: the endpoint, the required inputs, and the 10-credit Tier 1 cost. It does not address edge behavior (e.g., non-letter characters in the name) or rate limits.

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?

Extremely compact and front-loaded: the core computation is the first sentence, and the bracketed metadata lines are scannable. Nearly every token earns its place, though the group/endpoint lines duplicate information already obvious from the tool name.

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 not be described, and the required parameters and cost are stated. What is missing for a calculation tool in a dense family of near-identical siblings is any hint of when this variant is appropriate versus the other systems or number types.

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 coverage is 50%: 'fields' and 'precision' are documented in the schema, while 'name' and 'date' are bare. The description partially compensates by clarifying that 'name' means the full birth name, but says nothing about the date format or why a birth date matters to a name-derived number.

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 and resource ('Calculate the Personality number') and scopes it precisely to 'the consonants of the full birth name,' which distinguishes it from the soul-urge siblings that use vowels. The 'Mathers strict' system tag separates it from the non-strict kabbalistic and pythagorean variants, though it never names a sibling directly.

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 gives no when-to-use guidance and no selection criteria against the many alternative systems (chaldean, pythagorean, non-strict kabbalistic) or against the other number types in the same family. The only usage-adjacent signal is the cost line, which tells the agent it is a paid call but not when it is the right call.

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