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

With no annotations, the description carries the full burden and delivers: no auth required (keyless), no cost, SSRF-guarded safety posture, one-URL-at-a-time throughput limit, and the non-obvious capability that JS/SPA pages are rendered without a browser. That is behavioral context an agent cannot infer from the schema.

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?

Front-loaded with the value proposition ("Free keyless live web read") followed by output shape, safety, and the paid upgrade path. Dense but every clause carries information; nothing is redundant with the schema.

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, and the description compensates by naming the returned fields (title, metadata, main text, injection flag). It also covers the auth, cost, and safety dimensions that annotations would normally supply, so nothing essential is missing for a single-parameter read tool.

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?

One parameter at 100% schema coverage, so the schema already defines it as a public http(s) URL. The description adds only the practical constraint that it must be public and that only one is accepted per call — useful but marginal over the schema.

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?

Names a specific verb (fetch) and resource (ONE public URL) and enumerates the return payload: title, metadata, boilerplate-stripped main text, plus an injection-screen flag. It explicitly contrasts itself with the paid /web/extract, so an agent can distinguish it from siblings without opening any 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?

States the selection conditions directly: free, keyless, single URL ("ONE public URL now"). It then names the alternative and the exact conditions that route to it (Markdown, full link graph, 10-URL batches) and gives the follow-up call (get_premium_access) with pricing.

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