format_number

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

No annotations are provided, so the description carries the full burden. The description discloses the supported formats but does not state that this is a pure/read-only transformation, what it returns (a string), or any error behavior. It is not misleading, but it leaves basic behavioral aspects unstated.

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 sentence that front-loads the core action ('Format a number') and immediately provides concrete examples of each format. There is no redundant or filler content; every word contributes to clarifying the tool's purpose.

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?

The description, combined with the fully-documented schema, covers all supported formats and parameter roles. It does not explicitly state the return type, but this is strongly implied by the formatting intent. No critical information for calling the tool is missing.

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 the schema already documents all parameters. The description adds illustrative examples (e.g., $1,234.56) but does not add meaning beyond the schema's parameter descriptions. Baseline 3 is appropriate.

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 (format) and resource (a number) and enumerates the supported formats (currency, percentage, scientific, binary, octal, hexadecimal, significant figures, thousands separator), which clearly distinguishes it from sibling tools like calculate or convert_units.

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?

The description implies the tool is for formatting numbers but does not explicitly state when to use it over percentage_calc or other siblings. There is no mention of exclusions or conditions. For example, when should an agent choose format_number with format='percentage' rather than percentage_calc? This is left to inference.

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