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 one genuinely useful behavioral fact not in the annotations: the cost of 10 credits (Tier 1). It says nothing about permissions, rate limits, or what happens with an invalid date.

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 operative sentence comes first, followed by sharply delimited metadata tags. The alias note is parenthetical and skimmable, though it is arguably redundant with the sibling list.

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, and the cost/system metadata is present. However, the unexplained `date` parameter and the absence of any tie-breaker against the six other soul-urge siblings leave a real gap for an agent choosing among near-identical tools.

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 not. The description partially compensates by clarifying that `name` must be the full birth name and that only its vowels are used, but it never explains what `date` is for in an all-vowel calculation, so half the gap remains.

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 Soul Urge number') plus the derivation ('from the vowels of the full birth name') and names the system ('Kabbalistic (Mathers strict)'). This separates it from the Chaldaic/Pythagorean/Vedic soul-urge siblings, though it never contrasts 'Mathers strict' against the plain kabbalistic soul_urge sibling, leaving that distinction to the reader.

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?

No when-to-use or when-not-to-use guidance. The parenthetical only says it is a 'Cursor-friendly alias' for the canonical tool, which is a routing fact rather than a usage rule, and there is no indication of when to pick Soul Urge over Expression, Life Path, or the non-strict kabbalistic variant.

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