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

Annotations already cover the safety profile (readOnlyHint, openWorldHint=false, destructiveHint=false). The description adds real behavioral context beyond them: a metered payment model with a daily free allowance and per-call USDC cost via x402, plus no account or API key required. It stops short of describing what the response contains.

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 opening sentence is duplicated verbatim ('Did B really beat A, corrected for how many variants you compared' appears twice), wasting roughly half the prose. The remaining pricing and example content is front-loaded and useful, but the repetition is a clear structural flaw.

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 statistical test with four required numeric inputs and no output schema, the description explains the computation but never indicates what the agent gets back (p-value, lift, significance verdict). Pricing and auth are covered, but the result contract is left implicit.

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 100%, though the per-field descriptions are only 'example: N'. The description echoes a full example request, reinforcing that the four required params are counts (n_a, conv_a, n_b, conv_b) for each variant. This is useful but adds little beyond the schema's own example, so the baseline 3 applies.

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 states a specific analysis: whether variant B beat variant A, corrected for the number of comparisons. The verb+resource (significance test on A/B counts) is clear. However, it does not differentiate itself from statistical siblings such as multipletest, samplesize, or clusteredt, which an agent may confuse it with.

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 explicit when-to-use or when-not-to-use guidance, and no alternative tool is named despite several statistical siblings. The only contextual cues are availability and pricing (free allowance, then x402), which say nothing about when this tool is the right choice.

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