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

No annotations are provided, so the description carries the full behavioral burden, and it discloses nothing: no output format, no input type constraints, no error behavior, no edge cases. Even the hint that this is a pure transformation is only implied by the name.

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?

It is short, but shortness here reflects under-specification rather than efficient communication — the single 'sentence' is a tautological restatement of the title.

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 with no annotations, no output schema, and a vague parameter description, the definition is completely inadequate to tell an agent what 'format decimal' produces or how it differs from the many adjacent formatting tools.

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% with a single parameter, so the baseline is 3. However, the schema's own description ('Value to process') is generic and the tool description adds no meaning about what format the input string should be in or what the output looks like.

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 'Format Decimal: Format decimal' essentially restates the tool name twice, giving no detail about what formatting means (rounding, padding, precision, locale). An agent cannot distinguish it from siblings like x402-format-fixed, x402-format-significant, or x402-round-to.

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?

No when-to-use guidance, no alternatives, no exclusions. In a catalog of hundreds of sibling x402-format-* tools, this leaves the agent with no basis for choosing this one.

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