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

Annotations already declare readOnly, idempotent, non-destructive behavior. The description adds genuinely useful operational context beyond that: the POST endpoint, the required inputs, and a 10-credit (Tier 1) cost. It does not describe output format, but an output schema exists to cover that.

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-loads the purpose in one sentence, then uses compact bracketed metadata blocks for group/endpoint/required/cost and a parenthetical alias note. Efficient and scannable, with no wasted prose.

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 calculation tool with an output schema and full safety annotations, the definition supplies the endpoint, cost tier, required inputs, and system disambiguation. The only real gap is the unexplained 'date' parameter, which the schema does not describe either.

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 phrase 'full birth name letters (all letters, reduced)' usefully clarifies what 'name' must contain, but the role of 'date' in an Expression-number calculation is never explained.

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') and resource ('Expression (Destiny) number from full birth name letters'), names the system (Kabbalistic / Mathers strict), and explicitly identifies itself as a Cursor-friendly alias for the canonical sibling. An agent can distinguish it from the pythagorean/chaldean/vedic expression tools without opening the schema.

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?

Usage is implied by the system tag and the alias note, and required parameters plus cost are stated, but there is no explicit when-to-use/when-not guidance or comparison against the non-strict Kabbalistic expression sibling or other systems' expression tools.

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