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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the description's only job is to add context; it adds none. Notably it does not explain why a "lookup" is flagged non-read-only (e.g., billing or side effects via an x402-style endpoint), nor any rate limits or auth needs. It does not contradict the annotations, but it is silent on behavior.

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 a single front-loaded sentence fragment with no wasted words. Its brevity, however, comes at the cost of under-specification rather than efficient information density.

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?

An output schema exists, so return values need not be explained, and only one parameter is accepted. Even so, the definition omits what the lookup value should look like and any behavioral context for a non-read-only tool, leaving real gaps for a one-call API surface.

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% for the single required "lookup" parameter, so the description must compensate and largely does not. "By domain" weakly implies the value is a domain name, but there is no format guidance (bare hostname vs URL, subdomain handling), which matters since additionalProperties is false and the value is required.

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?

"JSON lookup for technology and metadata by domain" names a verb (lookup) and the resource/data returned (technology and metadata keyed by domain), which adds a little beyond the name and title. But it is close to a restatement of "Domain API" and gives no sense of what distinguishes it from siblings such as domain-api-json or domain-lookup.

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?

There is no when-to-use or when-not-to-use guidance, no mention of prerequisites, cost, or auth, and no routing to any alternative tool. The agent must infer usage entirely from the one-line purpose statement.

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