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

With no annotations, the description carries the full burden and does disclose a highly non-obvious trait: the MCP call does not perform the check, it returns payment requirements, and settlement happens via a separate POST with x402 headers, including the exact cost. It omits what a settled response contains and whether the payment requirement is returned every call or only once.

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?

Two tightly packed sentences with the cost and the two-step settlement path up front; nothing is redundant. The density is high but the ordering is sensible, leading with price and purpose before the mechanics.

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 two-parameter tool with no output schema, it covers purpose, cost, and the settlement path an agent must follow, which is the critical missing piece. It stops short of describing the shape of a successful 'changed' result or the payment-requirements payload, so an agent still has gaps after a successful settle.

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 compensate. It usefully clarifies that 'since' accepts either a hash or a timestamp, which the schema does not say, but adds nothing about the 'url' parameter or format constraints, leaving half the parameters 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 operation: determine whether a page changed since a given hash or timestamp. The verb+resource is clear and distinct from siblings like scrape_markdown or extract_structured, though it never explicitly contrasts itself with check_url, which sounds closely related.

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 only implied by the phrase 'since a hash or timestamp' — an agent can infer this is a conditional re-check tool. There is no explicit statement of when to prefer it over check_url or scrape_markdown, and no exclusions or prerequisites beyond the payment note.

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