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

With no annotations, the description carries the burden and does so well: it discloses the Cloudflare edge fetch, ~0.5 s latency, that unreachable pages are not charged, and the $0.003 x402/USDC price. It also names the returned fields and the injection-scan coverage (visible, hidden HTML, comments, invisible Unicode), though it omits truncation and rate-limit behavior.

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?

Dense but front-loaded: the core purpose leads, then metadata, then safety scan, then cost/latency. Every clause carries information, though the parenthetical and field list make it heavier than it needs to be.

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?

No output schema and no annotations, so the description must double as the return-value contract, and it does by naming the metadata fields and the injection scan. The one hole is max_chars behavior and any truncation/failure semantics.

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 only 50%: url is documented as 'Public http(s) URL' while max_chars has no description anywhere. The description adds nothing about either parameter, so the undocumented max_chars semantics (truncation vs. error, units, default) remain a real gap.

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 concrete verb and resource: converts a web page to markdown, main content only, and enumerates the metadata returned. It is clearly distinguishable in substance from search-oriented siblings, but it never names web_fetch or web_search_read, which is what a 5 requires.

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 'for LLM agents' and the prompt-injection scan framing, so an agent can infer this is the read-one-page-plus-safety-check tool. There is no explicit when-to-use/when-not or routing to web_fetch, web_search_read or prompt_injection_check.

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