domain_rank

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

With no annotations, the description carries the full behavioral burden. It usefully discloses the cost and payment rail ('costs 0.05 USDC on Base via x402') and the response content, but stays silent on rate limits, whether repeated calls re-charge, and permission/auth needs. The cost signal is genuinely valuable, but a paid read operation warrants more disclosure.

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?

A single dense sentence that front-loads the purpose and trails the cost as a parenthetical. Nothing is wasted, though cramming scope and billing into one sentence slightly blurs the reading priority.

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 4-parameter, no-annotation, no-output-schema tool, the description should say more: it omits the return shape, the meaning of the position buckets, and any routing against the many sibling ranking/traffic tools. It covers purpose and price adequately but leaves real gaps.

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 50%: target and confirmNewPurchase are documented, while language_code and location_code are not described in either schema or description. The description's phrase 'of a domain' loosely maps to target but adds no syntax or format detail, so it fails to compensate for the coverage gap. Baseline 3 is appropriate.

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 gives a specific verb+resource framing: 'Organic visibility overview of a domain', and enumerates the payload ('keyword counts by position bucket plus estimated traffic'). This is clear enough to distinguish it as a summary/overview tool, though it never names related siblings like ranked_keywords or traffic_estimate that an agent might confuse it with.

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?

There is no explicit when-to-use guidance and no named alternatives, despite several overlapping siblings (ranked_keywords, traffic_estimate, keyword_metrics, competitors). The only usage-adjacent detail is the pricing note, which tells the agent nothing about when this tool is the right choice.

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