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

Goes well beyond the annotations: it discloses pricing ($0.002/call, first 25 free, failures and bot walls uncharged), explains why repeats cost money (reinforcing idempotentHint=false), caps output at 100,000 characters, and limits scope to static HTML rather than rendered pages. That is exactly the extra context annotations cannot carry.

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?

Purpose is front-loaded and most clauses earn their place (formats, limits, pricing, JS caveat). It is a dense semicolon-chained paragraph, though, and the 'Example: url=https://example.com' clause is near-zero value 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 still characterizes the return value (clean text or Markdown with headings, code blocks, tables and links preserved) and the size cap. Combined with pricing and the static-vs-rendered distinction, an agent has everything needed to call it correctly and predict cost.

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 url, format, section and maxChars are all already documented. The description echoes the Markdown/text format and the 100,000-character ceiling but says nothing about the optional 'section' parameter (visible HTML ID), so it adds almost no meaning beyond the schema — baseline 3.

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 ('fetch any public web page URL') and the output shape ('main content as clean text or Markdown'), which separates it from siblings like html_to_text or extract. It also routes JavaScript-rendered pages to /extract/rendered, so an agent can tell it apart from the rendered-page variant without opening either 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?

"Use to read articles, docs and product pages at scale" gives concrete usage, and the JS-rendering note implicitly excludes one class of pages. It stops short of naming the sibling tool (only the /extract/rendered path) and gives no guidance on when to prefer extract, contents, or search_web instead.

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