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

With no annotations, the description bears the full disclosure burden. It reveals the tool's multi-step behavior (DNS resolution, HTTP fallback, bot-recognition, parked-page detection) and explicitly states it will not falsely claim a live page belongs to a different business. This is exceptionally transparent and goes far beyond generic wording.

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 description is front-loaded with a plain-language purpose and every clause in the following sentence adds value to understanding scope and edge cases. The enumeration of four outcome categories is dense but not redundant; it slightly sacrifices readability for completeness, which justifies a 4 rather than a 5.

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 single-parameter tool with no siblings, the description is very complete: it covers input, the technical checks performed, read-only behavior, and key result categories. The main gap is that there is no explicit statement of the return value shape, which matters more because there is no output schema.

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?

The schema already documents the single parameter (domain) as 'A hostname or URL' with 100% coverage. The description adds the behavioral nuance that the tool checks both apex and www, but it does not offer additional format, validation, or normalization instructions beyond the schema, so the baseline 3 applies.

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 concrete question ('Is this business's website still there?') and then specifies the exact technical scope: checks apex AND www, resolves DNS over HTTPS, falls back to plain HTTP, and distinguishes four distinct outcomes. This is a clear verb-resource pairing that makes the tool's function unmistakable even without siblings to differentiate from.

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 opening question signals a clear use case: verify whether a business's website is still live and reachable without being fooled by parked pages or bot-blocking. It does not list alternatives or exclusions, but there are no siblings, and the read-only statement plus outcome breakdown gives enough contextual guidance for when to invoke it.

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