Check a domain or link

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so safety is covered; the description adds genuinely new behavioral context by enumerating the verdict values, the risk signals evaluated, and the advice field. It stops short of stating rate limits, latency, or behavior on malformed input.

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 sentences, front-loaded with the purpose and followed by the return contract; the parenthetical lists are dense but each item is informative. Slightly list-heavy, but no filler sentences.

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 no output schema, describing the verdict, risk score, reasons and advice field is exactly the missing information, and the accepted input form is covered too. Only minor gaps remain, such as error handling and whether results are cached.

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 0% and the single property has no title-level detail, so the description carries the burden — and it does, explicitly stating it accepts either a bare domain or a full URL. That is the key ambiguity an agent would otherwise face, though input normalization rules (e.g. schemes, ports, trailing paths) remain unstated.

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 opens with a specific verb and resource ('Check whether a domain or URL is safe to open') and names the underlying resolver, which distinguishes it from the plain 'resolve' sibling. It is clear what the tool produces, though it never explicitly contrasts itself with 'resolve' or 'service_status'.

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 only implied: 'safe to open' suggests a pre-visit safety screen rather than raw resolution, which hints at the boundary with 'resolve'. There is no explicit when-to-use/when-not statement and no named alternative, leaving the agent to infer routing between siblings.

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