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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description adds genuine behavioral context annotations cannot: a rate/access model ('a few free samples a day') and per-call pricing ($0.002 USDC via x402). It also discloses the return entities, though not error or failure modes.

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 with the purpose front-loaded ahead of the pricing note. No filler; every clause carries information, though the pricing sentence could arguably be deferred to separate documentation.

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?

Output schema exists, so return values need not be enumerated, and parameter coverage is full. Combined with the disclosed pricing and result contents, the description is complete enough for an agent to invoke it correctly; only explicit when-to-use routing against siblings is missing.

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 the schema already documents both url and user_agent, making 3 the baseline. The description's mention of Googlebot/GPTBot/ClaudeBot loosely hints that user_agent selects a crawler identity, but adds little syntactic or format detail 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?

The description names a specific resource (robots.txt fetchability) and states exactly what the result contains: the crawler's permission decision, the deciding rule, and declared sitemaps. It is clear what the tool does, though it does not explicitly differentiate itself from siblings like seo__page-audit or seo__links.

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?

The description gives no when-to-use guidance and never names an alternative or condition for choosing this over sibling SEO tools. Usage is only inferable from the subject matter (robots.txt checking).

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