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

With no annotations, the description carries the full burden and does well: it discloses that the call is paid ($0.01 USDC on Base or Solana), requires no account or API key, is capped at 200 KB, and that failed calls are not charged. It stops short of describing redirect handling, non-HTML responses, timeouts, or rate limits.

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-loads the most decision-relevant fact ('Paid.') and packs cost, limits, auth, and error policy into a few dense sentences. The trailing bare endpoint URL is mild filler for an agent but is defensible as payment context.

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?

For a one-parameter tool with no output schema and no annotations, the description covers price, payment rails, size cap, auth model, and billing on failure — the things an agent needs before spending money. Return-value explanation is unnecessary since the payload (raw HTML) is stated inline.

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?

Only one parameter exists and the schema already documents it at 100% coverage ('Page URL, http(s)'). The description's 'any public web page' adds a scope hint (public, not authenticated) but no format or syntax detail beyond the schema, so the baseline of 3 applies.

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 and get its raw HTML'), which separates it from siblings like buy_fetch_fetch-headers and buy_fetch_fetch-meta that return different artifacts. It never names those siblings explicitly, so an agent must infer the distinction from the word 'raw HTML'.

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 rather than stated: 'any public web page' plus a raw-HTML payload tells the agent this is for full page bodies, not headers or metadata. There is no explicit when-not guidance, no mention of JS-rendered pages, and no pointer to a sibling alternative for those cases.

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