Expression / Destiny (chaldean)

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds useful context by disclosing the cost ('10 credits (Tier 1)') and the endpoint, but it does not discuss authentication, rate limits, or output behavior beyond what the output schema covers.

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 description is short and front-loads the purpose, followed by structured metadata (group, endpoint, required fields, cost). Every line adds value, though the bracketed metadata reads slightly like a list rather than 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?

Given the simple calculation, rich annotations, and an existing output schema, the description covers purpose and cost. However, it leaves the 'date' parameter unexplained and provides no usage guidance relative to the many sibling numerology tools, leaving gaps for an agent to infer.

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?

With 0% schema description coverage, the description must compensate. It partially clarifies the 'name' parameter ('full birth name letters') but says nothing about the required 'date' parameter—why it is needed for an Expression number calculation or what format is expected beyond the schema pattern.

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?

The description states a specific verb ('Calculate'), resource ('Expression (Destiny) number'), and the exact input method ('from full birth name letters, all letters, reduced'), plus the Chaldean system. This distinguishes it from date-based numbers and other numerology systems, though it does not explicitly name a sibling to avoid.

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 calculation definition: an agent can infer it is used when a Chaldean Expression number is needed, not Life Path or another system. However, there is no explicit when-to-use versus alternatives, and no exclusions or conditions are given.

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