Compare domain infrastructure

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

Annotations already cover read-only, idempotent and non-destructive traits, and the description adds substantial non-obvious behavior: it returns the underlying records plus unavailable checks, makes no HTTP/TLS connection, warns that shared hosting makes matches non-conclusive of ownership, and notes RDAP cache can be six hours stale.

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?

Four short sentences, front-loaded with the core purpose, then return shape, then two high-value caveats. No filler; every sentence earns its place.

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 explains the return content (records per match plus unavailable checks). It also covers freshness and interpretation limits, so an agent has everything needed to call and read the result correctly.

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 single param is already documented (2-6 domains or URLs). The description adds no parameter-level detail such as URL normalization or the item limit, so it matches the baseline of 3 when the schema carries the full burden.

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 states a specific verb (find/compare) and resource (shared IPs, nameservers, mail servers, registrars) and the methodology (DNS and RDAP). It clearly distinguishes itself from single-lookup siblings like domain_whois or dns_lookup by being a cross-domain correlation tool.

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?

Usage is implied rather than stated: an agent can infer this is for finding shared infrastructure across multiple domains. However, no alternatives are named and there is no explicit when-to-use/when-not guidance against siblings such as domain_whois or recon_domain.

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