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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the bar is lower, yet the description still adds rate-limit context ('capped per day'), pricing awareness (0.01 USDC), and the shape of the return (source URL, retrieval time, content hash). It does not say what happens when the daily cap is hit or how failures are surfaced, which keeps it below a 5.

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?

Three compact sentences, front-loaded with what the tool does, then the limits, then the decision rule. No filler; each sentence carries distinct information.

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?

There is no output schema, but the description covers the return content (up to three cited excerpts plus URL, retrieval time, content hash), the daily cap, and the absence of a verdict. That is everything an agent needs to call it correctly and interpret the result.

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% and the schema text already explains both fields, including that the paid tool accepts up to five URLs. The description restates the 'one question and one public URL' contract without adding format or constraint detail beyond the schema, 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?

States a specific verb and resource ('give one question and one public URL', get 'up to three cited excerpts') and explicitly positions itself as the free preview of the paid tool. It names the sibling research_evidence and what that tool adds, so an agent can distinguish the two without opening either schema.

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?

Gives an explicit selection rule: use this 'to judge whether the paid call is worth 0.01 USDC', and states that assessment/verdict belongs to research_evidence over up to five sources. When-to-use, when-not-to-use, and the alternative are all named.

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