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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so 'Read-only' is largely redundant. However, 'Cannot spend money' adds real context not present in annotations (relevant given budget/pricing siblings), and the enumerated response fields substitute for the missing output schema.

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?

Three tight sentences with no filler; the capability and returned fields come first, then usage triggers, then the safety/cost constraints. Every sentence carries distinct information.

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, the description usefully lists the returned surface, and annotations cover safety. The remaining gap is the input format of 'domain', which an agent must guess — a small but real deficit.

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?

There is a single required parameter at 0% schema description coverage, and the description never clarifies the expected format (bare domain vs. full URL, whether protocol/path is accepted). The word 'domain' is the only hint, leaving real ambiguity for the caller.

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 verb (Fetches) and resource (a live domain's observable surface) and enumerates exactly what is inspected: HTTP status, redirect target, title, meta description, h1s, tech hints. It is clearly a site inspection tool, though it does not explicitly differentiate itself from the close siblings check_live and fetch.

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?

Gives concrete usage triggers: 'what is wrong with a site they own', 'what is deployed at a domain', 'whether it serves anything at all'. That is strong positive guidance, but there are no explicit exclusions naming check_live/fetch/verify_ownership as alternatives for overlapping cases.

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