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

No annotations are provided, so the description carries the burden. It implies a safe, side-effect-free arithmetic computation and volunteers the x402 payment context (five free calls per signed wallet), which is genuine behavioral information. However, it does not say what happens after the trial is exhausted, how the numeric strings are parsed, or how errors (non-numeric input) are handled.

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 core sentence is front-loaded and complete, with the formula stated inline. The trailing free-trial emoji line is promotional rather than operational and dilutes a tight definition slightly, but the overall length is appropriate.

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 low-complexity two-parameter calculation tool, the description covers purpose, derivation, and the return value ('returns the difference'), which stands in for the absent output schema. It leaves a gap on input format (both params are untyped strings with no description) and edge-case behavior, so it is adequate but not complete.

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%, so the description must compensate. The formula 'current assets minus current liabilities' does map both parameters (currentAssets, currentLiabilities) to their roles, adding real meaning. It does not, however, clarify that the values are numeric strings, whether decimals/currency symbols are accepted, or the expected format.

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?

States a specific verb and resource ('Computes working capital') and even supplies the formula (current assets minus current liabilities), so an agent knows exactly what is produced. It does not differentiate from closely related liquidity siblings such as x402-current-ratio, x402-quick-ratio, or x402-cash-conversion-cycle, which keeps it out of the top tier.

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 statement of when to use this tool versus the many other financial-ratio siblings, nor any prerequisites or exclusions. The only extra text is a free-trial promo ('5 free trial calls per signed wallet'), which is not usage guidance. An agent must infer the context entirely.

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