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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds genuinely non-structured behavior: a free daily sample quota and $0.003 USDC per call via x402, which an agent must know before invoking. It does not describe output shape, but the output schema covers that.

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 tight sentences, zero filler. The functional description is front-loaded and the cost/rate caveat follows, so an agent gets purpose first and constraints second.

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 single-input read tool with an output schema, the description covers purpose, returned fields, and the unusual payment/quota model. Only the lack of sibling routing keeps it from being fully complete.

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 with 100% schema description coverage, so the schema already documents 'url'. The phrase 'on a page' loosely confirms the single input but adds no format, scope, or crawling semantics beyond 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?

States a specific verb-like action (extract links) and resource (a page), plus the returned fields (anchor text, nofollow flags). It is clear what the tool produces, though it never names a sibling such as seo__page-audit to sharpen the boundary.

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 by 'links on a page' and the pricing line tells the agent there is a per-call cost after a free daily quota, which is a real invocation constraint. There is no explicit when-to-use/when-not guidance or routing against seo__page-audit or web__read.

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