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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds value beyond that with the pricing model ('0.006 USD per page'), the JavaScript rendering limitation, and the default robots.txt obedience — all operational facts an agent must weigh before calling.

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?

Four sentences, each carrying distinct load: capability and output shape first, then the rendering caveat, then compliance, then cost. No filler and no repetition of the title.

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 10 parameters and no output schema, the description does the right work by describing the row-per-page return and the summary-row behavior implied by max_charge_usd. It does not describe how rows are delivered (dataset vs. inline) or what a blocked/summary row looks like, which would help for a 10-parameter crawl tool.

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 100%, so every parameter including extract, proxy_mode, and obey_robots is already fully documented in the schema, including defaults and charging implications. The description adds no parameter-level 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 ('Crawl a website from a start address') plus the exact return shape ('one row per page with internal links, external links, file download links, HTML tables as rows, and lists'). An agent can tell precisely what it gets back without opening 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 a clear negative condition — 'No AI and no browser, so pages built by JavaScript return little' — which tells the agent when not to reach for this tool. No sibling tools exist, so no alternative routing is needed, but it stops short of positive guidance on when this crawl is the right choice (e.g., static sites, link auditing).

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