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

With no annotations, the description carries the behavioral burden. It discloses the screening mechanisms (blocklists, look-alike heuristics) and explicitly warns that absence of a flag is not a guarantee of safety. It does not state whether the operation is read-only or describe side effects, but as a 'check' it is reasonably transparent.

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 with no filler. The core purpose is front-loaded, and the caveat is concise. Every word adds value.

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?

The description covers purpose, heuristics, and a key caveat, but does not describe the return format or how the result should be interpreted (e.g., boolean, risk score). Since there is no output schema, this is a notable gap for an agent deciding how to act on the result.

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 100% and the parameter description includes an example, which is sufficient. The tool description does not add additional semantic detail beyond the schema, but the baseline of 3 is appropriate given full coverage.

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 clearly states the tool checks whether a URL is a known phishing/fake site, with a specific verb and resource. It distinguishes itself from siblings (check_address, check_contract_safety, etc.) by focusing on URLs, making the purpose unambiguous.

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?

It gives a clear usage context ('before connecting a wallet') but does not explicitly mention alternatives or exclusions. However, the resource type (URL) makes it distinct from siblings, so the intended use is reasonably clear without listing when not to use it.

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