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

Annotations cover only the safety profile (readOnly, non-destructive, open-world), and the description adds substantial non-obvious behavior: free solutions are ordered first, VPN providers appear only when a regional block is suspected, ordering uses documented criteria without commission, sponsored offers appear regardless of assessment/cache state, and affiliate links must not be opened automatically. That is real operational policy an agent could not infer from structured fields.

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?

The purpose is front-loaded in one clear sentence, but the remainder is a dense run-on that mixes output-field semantics, ordering rules and advertising policy into one paragraph. Much of that content is genuinely useful policy, yet it is hard to scan and partially duplicates fields the output schema already defines.

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 annotations covering safety and an output schema covering return shape, the description supplies the missing policy layer — ordering, disclosure obligations and how sponsored content must be presented. Coverage is strong for a read-only lookup; only operational limits (rate limits, cache freshness/expiry semantics) are absent.

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 all three parameters are already documented, including the enum and the visitor_reported condition — and the description largely repeats that same visitor_reported explanation. It adds only marginal extra meaning (the HTTP 451 → news_or_legal_block default rationale), so the 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?

States a specific outcome — 'Ways to reach a website that may be blocked in a country or region (geoblocking)' — which is clearly a different job from siblings like check_website or check_agent_readability. It also ties itself to those siblings by explaining it consumes the cached check result, so an agent can place it in the workflow. It stops short of explicitly naming the sibling tools it supersedes.

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 rather than stated: you call it when a site may be geoblocked, and the input notes cover the visitor-reported case. There is no explicit when-not guidance and no named alternative (e.g. 'use check_website first if you have no cached result'), which matters because a sibling does the underlying check.

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