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

Annotations only declare readOnly and openWorld; the description adds substantial behavior beyond them: deterministic extraction with no LLM, the exact field set returned, a known unsupported domain, and the payment model ($0.005 USDC per call via x402 on Base). Cost and auth mechanics are exactly the kind of 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?

Three short sentences, front-loaded with purpose, then return fields, then constraints and price. No filler; each clause (supported sites, no-LLM, unsupported domain, cost) carries information the agent cannot get from schema or annotations.

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 usefully enumerates return fields (title, author, published date, paragraphs, images, links), which is the main thing an agent needs. It is nearly complete; the only material gap is the unexplained max_chars behavior, which could lead to unintentional truncation.

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 the parameter burden. 'url' is self-evident, but max_chars is never mentioned — no hint that it truncates output, what the default is, or how it interacts with the 'clean paragraphs' return. This leaves one of two parameters entirely undocumented.

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 ('Read') and resource ('Korean web page as clean text') and enumerates the exact supported shapes: Naver Blog iframe posts, Naver/Daum News articles, generic pages. This is clearly distinguishable from every sibling tool, which are structured-data APIs rather than page readers.

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 concrete scope (which site types work) and an explicit exclusion ('Naver Cafe is reported as unsupported'), which is real when-not guidance. It stops short of naming alternative tools or stating prerequisites for using it versus other fetchers, so it is clear context rather than a full routing rule.

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