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

With no annotations present, the description carries the full behavioral burden and does so: robots.txt compliance, which page classes are skipped, the assurance that skipped pages are never charged, the exact free quota, price, chain and currency, plus the payment retry mechanism. Beyond the safety profile it also enumerates the returned payload fields, so an agent knows what comes back and what costs money.

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 sentences, front-loaded with the capability and output contract, then constraints, then the commercial path. Dense but every clause (robots.txt, never charged, price, retry header) is load-bearing. Slightly packed in sentences 2-3, which could be split for scannability.

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 exists, yet the description enumerates the return fields (title, description, links, word_count, token_estimate) and the format variants, and it explains the error and payment edge cases. For a 2-parameter, read-only fetch tool this is complete enough to call correctly on the first attempt.

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 both parameters are already documented and the baseline is 3. The description adds meaning by framing the tool's output as Markdown-oriented ('LLM-ready Markdown'), which helps interpret the format enum, though it still leaves the fact that json is the default to the schema. A minor gain over the schema.

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?

A precise verb+resource ('Fetch one public web page') followed by an explicit contract for the output: clean main-content Markdown with nav/footers/ads stripped, absolute links, tables preserved. That distinguishes it from a generic fetch or a search/lookup sibling without needing the 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 strong when-not guidance ('skips login walls, paywalls and 401/403 pages') and a concrete operational procedure for the paid path (retry with the PAYMENT-SIGNATURE header after 3 free pages/day). It never routes the agent to a named sibling such as lookup or discover, so it stops short of a 5.

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