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

No annotations are supplied, so the description carries the full behavioral burden. It discloses the read-only operations performed, but never states that this is a non-mutating lookup, whether rate limits or quotas apply, how exhaustive subdomain discovery is, or whether the target must be externally resolvable.

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?

A single front-loaded sentence naming the domain, followed by the concrete capability list. Nothing is padded, though the five-item enumeration is dense for a one-sentence description.

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 and no annotations, the description usefully enumerates the return categories (records, provider, tech stack, registration dates, subdomains), which is the essential missing context. Gaps remain around cost, limits, and result depth, but the core is covered.

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?

Only one parameter, and schema coverage is 100% — the schema already documents 'domain' with examples ('stripe.com', 'vercel.com'). The description adds no format or normalization detail (e.g., whether a full URL with path is accepted). 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 names a specific domain and enumerates five concrete capabilities (DNS record resolution, email provider identification, SaaS stack detection via TXT, RDAP registration lookup, subdomain discovery), so an agent knows exactly what comes back. It stops short of explicitly differentiating itself from siblings like security_audit or github_intel, which also touch domain/company reconnaissance.

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 framing, no prerequisites, and no mention of alternatives such as security_audit or web_extract that overlap in scope. Usage is only inferable from the capability list, which is not the same as guidance.

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