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 new behavioral context beyond structured fields: cost (10 credits, Tier 1) and the exact endpoint. It does not mention auth requirements or rate limits, which would round it out.

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?

Front-loaded with the core computation in the first sentence, followed by compact bracketed metadata. Every element is short and useful, though the 'Required: name, date' line partly duplicates the schema's required array.

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 low-complexity two-required-param calculation with an output schema present, the definition is nearly sufficient: name semantics, system, cost, and endpoint are all covered. The remaining gap is the absence of any 'date' semantics and any usage context relative to the dense sibling set.

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%: the two required params (name, date) carry no schema descriptions, while fields/precision do. The description clarifies that 'name' means the full birth name in letters, which is a real semantic gain, but it never explains what 'date' represents (presumably birth date) beyond re-stating it as required.

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 (Calculate), resource (Expression/Destiny number), input basis (full birth name letters, all letters, reduced), and system (Pythagorean). This cleanly separates it from the chaldean/kabbalistic/vedic expression siblings and from soul_urge/personality, which use vowels/consonants rather than all letters.

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 says what the tool computes but gives no when-to-use, when-not-to-use, or routing advice among the ~70 sibling numerology tools. The system choice is embedded in the name, but no explicit selection guidance or prerequisites are offered.

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