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

With no annotations supplied, the description usefully discloses that the tool is free, requires no x402 challenge, and can be called directly; the GET equivalent also indicates a read-style retrieval. The reproducibility statement adds useful context, though operational details such as response format or rate limits are not covered.

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 purpose and contents are front-loaded, and the payment and HTTP details are practically useful. The wording is somewhat dense, and "no payment required" and "this tool is free" are mildly redundant.

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 zero-parameter criteria retrieval tool, the description supplies the service version, expected information, pre-payment purpose, reproducibility context, cost behavior, and HTTP equivalent. Despite the absence of an output schema, this is enough for an agent to select and invoke the tool correctly.

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?

The tool has zero parameters, so the baseline score of 4 applies and no parameter documentation is necessary. The description instead adds relevant invocation context through the service version and HTTP endpoint.

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 identifies the exact resource—the published criteria for stream-divergence/v1—and enumerates its contents, including artefact caps, comparison rules, and test corpus identity. This clearly distinguishes it from the sibling tools that perform a comparison or precheck rather than retrieve the governing criteria.

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?

"Read these before paying" provides clear guidance on when to consult the criteria, while "call directly without payment" explains how to invoke this tool. It would be stronger if it explicitly named stream_divergence_compare or stream_divergence_precheck as the next steps or alternatives.

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