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

No annotations are provided, so the description carries the full burden and does so richly: robots.txt compliance, SSRF protections (private/loopback/metadata hosts blocked), size and time caps (3 MB / 15 s), no auth, failed reads not charged, and per-call pricing via x402. This is exactly the behavioral context an agent needs before invoking.

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 core action and return payload, then constraints, alternatives, and cost, with no filler. Some clauses are telegraphic fragments ('HTML, plain text, Markdown, JSON and XML.'), but density here serves the agent rather than padding.

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 enumerates the returned fields, and it also covers limits, auth posture, failure billing, and cost. Nothing material for a correct invocation is missing.

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% and the single 'url' parameter is fully documented in the schema, so the description adds no parameter-level meaning beyond what is already there. Baseline 3 for high coverage with no additional param guidance.

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?

Specific verb ('Fetch') plus resource ('public web page') and a precise statement of the output shape ('clean Markdown ... title, url, final_url, markdown, word_count'). It also distinguishes itself from the sibling read_pdf ('For PDFs use read_pdf'), so an agent can route correctly 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?

Gives explicit when-not conditions ('Static fetch only (no JavaScript rendering)', 'no logins or paywall bypass') and names the alternative tool and the condition selecting it ('For PDFs use read_pdf'). Little is left to inference.

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