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

With no annotations, the description carries the full burden of behavioral disclosure. It states the core action but omits return format (e.g., integer count), handling of non-ASCII characters, whitespace treatment, and read-only nature. The only additional context is the trial-call/payment note, which is not core behavior.

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 stating the purpose, followed by a brief trial note. It is efficient and easy to parse, with no wasted wording.

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 simple counting tool, the definition still lacks essential parameter guidance (which of the two string params to use) and any return value description. With no annotations and no output schema, the description does not provide enough information to call the tool correctly without guessing.

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 0% and there are two parameters ('text' and 'input'), neither documented in the schema. The description implies a 'text' input but does not explain the 'input' parameter or which one to use, leaving parameter semantics ambiguous.

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 gives a specific verb ('Counts') and resource ('uppercase ASCII letters in text'), making the tool's function immediately clear. The 'ASCII' qualifier narrows scope, but it does not explicitly differentiate from siblings like x402-lowercase-count or x402-uppercase-ratio, 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?

There is no guidance on when to use this tool versus alternatives such as x402-lowercase-count, x402-uppercase-ratio, or x402-character-count. No conditions, exclusions, or sibling references are provided.

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