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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so safety is covered. The description adds genuinely non-structured context: an x402 micro-payment of $0.005 USDC per call (eip155:8453) and the guarantee that cookie values are never returned, only flags. It stops short of describing failure modes (timeouts, unreachable hosts).

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 first sentence duplicates the title, which is mild waste, but the rest is dense and front-loaded: capabilities first, then mechanism, then the pricing/limits caveat. 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?

With no output schema, the description does the heavy lifting by enumerating exactly what is returned, including the graded security audit and cookie flags. Missing only error/edge-case behavior and the HEAD-vs-GET tradeoff, which keeps it from a 5.

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 0%, so the description must carry parameter meaning. It does note that the URL is requested via HEAD or GET, but it doesn't explain the default (GET), when HEAD is preferable (headers-only, cheaper), or any URL constraints like the 2048-char max.

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 names a specific verb (requests a URL) and enumerates the concrete artifacts returned: final status, redirect hops, headers, latency, security-header audit with grade, and cookie flags. This clearly separates it from siblings like web_metadata, web_extract, or web_links, which focus on page content rather than transport-level diagnostics.

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?

Usage is implied by the output list (use it when you need status/headers/redirects/timing), and the HEAD/GET mention hints at usage modes. However, it never states when to choose this over web_metadata or web_extract, nor does it give exclusions or prerequisites beyond the price line.

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