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

No annotations are provided, so the description carries the burden. It does disclose a non-obvious behavioral trait: the pricing/gating model (5 free trial calls per signed wallet), which tells the agent about call limits and wallet-signing requirements. Beyond that it reveals nothing about return format or behavior.

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?

A single front-loaded sentence that names the tool and gives the formula immediately. The trailing free-trial marketing emoji is slightly noisy but adds pricing context, so size 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 two-parameter calculator with no output schema, the description covers purpose and formula adequately but leaves the string-typed inputs and expected return value unaddressed, which matters because the schema itself documents nothing.

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 is 0%, so the description must compensate. It does map both parameters to meaning (days inventory, days receivables) and states they are added together, but it omits that both are strings and gives no format or unit expectations, leaving a real gap.

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 (Computes), a specific resource (the operating cycle), and even gives the exact formula (days inventory + days receivables). This formula implicitly distinguishes it from the very similar sibling x402-cash-conversion-cycle, which would add days payables.

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 guidance on when to reach for this tool versus related siblings like cash-conversion-cycle or days-sales-outstanding, and no preconditions stated. For a simple calculator the implied usage (feed two inputs, get a result) is weak guidance at best.

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