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

No annotations are provided, so the description carries the full disclosure burden, and it discloses nothing: not whether the result is rounded, what happens with negative or zero percent, whether inputs are parsed as numbers from strings, or what the return shape 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?

It is short, but the brevity comes from under-specification rather than economy: the single clause is pure duplication of the tool name, so no sentence earns its place by adding information.

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 tool is simple (two optional string params, no output schema, no annotations), so it demands little, but the description still omits everything an agent needs to invoke it correctly: the numeric semantics of the string inputs and the direction of the operation relative to its increase counterpart.

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% (two params), which sets the baseline at 3 per the stated rule. However, the schema text is placeholder-grade ('Value to process', 'Percent to process'), and the description adds nothing to clarify that 'value' is the base amount and 'percent' is the reduction rate.

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 is a verbatim restatement of the title/name ('Decrease By Percent: Decrease By Percent'), which is a tautology rather than an explanation. The name alone implies a percentage-decrease math operation, but the description adds no scope, operand meaning, or output form, and does not distinguish itself from the clearly present sibling x402-increase-by-percent.

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 when-to-use guidance at all, and the obvious alternative (x402-increase-by-percent) is never mentioned even though it is the mirror operation. An agent must infer usage purely from the tool name.

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