Vehicle number numerology

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

Annotations already declare readOnly, idempotent and non-destructive, so the burden is light, and the description contributes the Chaldean method plus a concrete cost ('10 credits, Tier 1') and endpoint, which is genuinely useful. However it doesn't disclose output shape or what happens with edge-case inputs like plates exceeding the 20-character limit.

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?

One compact sentence plus a tidy metadata block listing endpoint, required parameter and cost. The comparative opener 'Same shape as the mobile number' is slightly indirect but doesn't waste space.

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 cost, endpoint and required parameter are covered. The unexplained 'date' parameter and the reliance on a sibling name to define the operation leave a visible gap for a 3-parameter tool.

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 only 33%, so the description needs to compensate. It clarifies 'number' (digit-by-digit) and 'countLetters' (Chaldean letter value, default false, letters are the state/district code) beyond what the schema already states, but the 'date' parameter is left entirely unexplained in both places.

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 names the resource ('a number plate') and the computation ('by Chaldean value'), so an agent knows this scores a vehicle registration number. It leans on a sibling for the verb ('Same shape as the mobile number'), which weakens standalone clarity, and it never literally says 'compute vehicle numerology'.

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?

It implies the rule for when letters matter ('only with countLetters'), which is the only real decision the caller makes, but gives no when-to-use versus when-not framing or pointers to the related mobile/house number tools. Guidance is implied rather than stated.

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