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

No annotations are supplied, so the description carries the full behavioral burden. It adds one genuinely useful fact (free-trial quota tied to a signed wallet), but says nothing about output shape, default parameter values, or what happens when rate and lambda are both omitted — a real risk for a sampler with two optional rate inputs.

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?

One front-loaded sentence stating the action, followed by a short pricing note. No filler or repetition. The emoji and free-trial clause are promotional rather than functional, but they occupy little space.

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 simple compute tool the bar is lower, but with no output schema, zero parameter documentation, and an unresolved rate/lambda duality, an agent cannot reliably invoke this. Adding the default rate and clarifying the alias would make the definition 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 coverage is 0% and both parameters are bare optional strings. The description does not explain the relationship between 'rate' and 'lambda', which appear to be synonyms for the distribution rate, nor which one wins if both are sent, nor whether values are plain numbers or expressions. This ambiguity is the main thing the description needed to resolve and it did not.

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 gives a specific verb and resource: 'Generate a random exponential number.' That is unambiguous about what comes back conceptually. It fails to differentiate from the many similar siblings such as x402-random-normal or x402-exponential-pdf, which an agent scanning a 900-tool namespace would need.

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 prerequisites, no alternatives. The only extra sentence concerns billing ('5 free trial calls per signed wallet'), not selection. An agent has no cue for choosing this over x402-random-normal or x402-exponential-pdf.

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