Takes a registration plate and an optional letters flag (A=1..Z=26) and returns the plate total, a single number 1 to 9, with every addition step. Example input: {"plate":"MH12AB3456","letters":false}
| Name | Required | Description | Default |
|---|---|---|---|
| plate | Yes | Vehicle registration plate, letters and digits only, e.g. MH12AB3456 | |
| letters | No | Also count letters as A=1 to Z=26; default false counts digits only |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden and does disclose the return shape: a single number from 1 to 9 plus every addition step. It does not mention determinism, error handling, or validation behavior beyond the schema, keeping it below 5.
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 a single, front-loaded sentence with a useful example and no wasted wording. The purpose, optional flag behavior, return value, and example are all packed efficiently.
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 two-parameter computational tool with no output schema and no annotations, the description adequately explains the calculation and return value. It could be more complete by clarifying the exact response structure and any error conditions, but the essentials are present.
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 100%, so both parameters are already documented in the schema. The description adds only a concise restatement of the letters flag mapping (A=1..Z=26) and an example input, which is baseline-level added value.
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-like operation ('takes a registration plate... returns the plate total') and resource (registration plate), making the core purpose clear. It does not differentiate from the sibling vehicleLuck, so it falls short of a 5.
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 description of the computation and the example, but there is no explicit guidance on when to use this tool versus vehicleLuck or when not to use it. No alternatives or exclusions are named.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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