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

With no annotations, the description carries the full burden and does unusually well: it discloses the $0.01 USDC on Base (eip155:8453) cost, the exact x402 payment location in params._meta, and the raw HTTP endpoint. This tells the agent about an auth/payment prerequisite that would otherwise be invisible. It doesn't cover failure behavior, rate limits, or what happens with no q and no url.

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 the core capability, followed by mode selection, then pricing and endpoint. Every clause carries information: sources, modes, cost, payment mechanism, HTTP path.

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?

With no output schema, the description must convey return shape, and it does at a high level ('ranked results', 'clean readable article text'). Combined with the payment disclosure, an agent has what it needs to invoke it. A bit more on how results and extracted text are structured in the response would close the remaining gap.

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 description coverage is 100%, so the schema already documents q, url, chars, and extract in detail. The description only restates the q/url mode selection and adds nothing about ranges or defaults beyond that. Baseline 3 applies since the schema does the heavy lifting.

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 compound verb+resource: search plus page-to-markdown extraction, naming the sources (Wikipedia, Hacker News, GitHub, a web engine) and the two operating modes. An agent immediately understands what it returns. It stops short of naming sibling tools like websearch__briefbatch or web_extract__extract, which would make the differentiation explicit rather than implied.

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?

It states the two invocation modes clearly: 'Pass q= to search, or url= to extract any single page,' and points to free /demo and /quickstart endpoints for trial. What's missing is when NOT to use it — e.g., when the batch sibling is preferable — and which mode is selected if neither parameter is supplied, given required parameters is zero.

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