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 burden is covered. The description adds genuinely useful non-structured context: a fixed price of 10 credits (Tier 1), the required inputs, and the endpoint. It does not describe the returned values, but an output schema exists so that is not a gap.

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 core purpose is front-loaded in the first two sentences, with the bracket metadata organized into scannable label/value lines. The block is slightly verbose relative to the tiny calculation it describes, but nothing is truly wasted.

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 single-purpose calculation tool, the definition covers system, endpoint, required inputs, and cost, while annotations carry the safety profile and an output schema covers returns. An agent has everything needed to call it correctly.

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 50%: `fields` and `precision` are documented in-schema but `name` and `date` are not. The description adds real meaning for `name` by specifying it is the full birth name and that only vowels are used, but it never explains why a `date` is required for a soul-urge calculation, leaving that parameter opaque.

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 from the vowels of the full birth name') and pins the system to 'Kabbalistic (Mathers strict)', which lets an agent separate it from the chaldean/pythagorean/vedic and non-strict kabbalistic siblings. The alias note ties it explicitly to astroway_numerology_kabbalistic_strict_soul_urge.

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?

Supplies clear operating context: the system group, the endpoint, the required inputs, and the cost tier, plus the cursor-friendly alias routing. It never states when this should be preferred over the canonical non-alias sibling or when not to use it, so there is context but no exclusions.

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