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

Goes well beyond annotations: hard caps (384KB response, 64KB body, 12s, 3 redirects), SSRF protection, no cookie propagation, upstream 4xx/5xx returned as charged data versus uncharged proxy errors, payment rail and per-call price, and an untrusted-content warning. The destructiveHint=true annotation is also coherent with the disclosed non-GET methods.

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-loads purpose, then invocation, then return shape, then limits, then cost/terms — a dense but well-ordered block where each clause carries a distinct constraint. No filler sentences.

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?

Despite no output schema, the description names every returned field and distinguishes data-bearing HTTP errors from proxy failures. Payment requirements, rate/size caps and trust level of returned content are all covered, leaving no gap an agent needs before calling.

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%, so the baseline is 3, but the description exceeds it by enumerating the accepted methods (GET/POST/HEAD/PUT/PATCH/DELETE) where the schema only says 'HTTP method', and by giving body/header size limits that bound the body parameter. The alternative POST JSON envelope shape is also clarified.

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 ('HTTP request proxy API for public URLs') plus the two call shapes, and enumerates the returned fields. It never contrasts itself with related siblings such as fetch, extract, screenshot or pdf, so an agent cannot tell from this text alone which of those to prefer.

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?

The 'public URLs' scope and 'private hosts blocked' rule imply when the tool is usable, and the two invocation forms are spelled out. But there is no explicit when-to-use/when-not guidance relative to fetch, extract or screenshot, which are the obvious alternatives in this sibling set.

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