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

No annotations are supplied, so the description is the only disclosure of behavior, and it says nothing. It does not state how numbers are humanized (e.g., commas, abbreviations, locale), what inputs are valid, or what the return format is.

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 but under-specified rather than concise; it repeats 'Number Humanize' twice and contains no useful structure. Every sentence should add information, and this one does not.

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 formatting tool where output conventions matter and no output schema or annotations exist, the description is completely inadequate. It does not mention types, examples, locale, or return values.

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 for the single parameter is 100%, and the description adds no parameter-level meaning beyond 'Value to process'. Baseline 3 applies because the schema carries the documentation burden, though the schema's own description is generic.

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 'Number Humanize: Number Humanize' is a tautology that just restates the tool name. It provides no specific verb, no resource detail, and no differentiation from the many sibling tools.

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 about when this tool should be used or preferred over alternatives. Siblings such as number-to-words, format-thousands, and seconds-to-human show that selection is non-obvious, so the complete absence of context or exclusions leaves the agent to guess.

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