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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It hints that the tool investigates ownership, reputation, and risk, implying aggregation across multiple data sources, but it never states whether live network lookups occur, whether host and domain are both expected, what happens on invalid input, or what the result looks like. For a multi-source research tool, this is a thin disclosure.

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 short, but it wastes the front-loaded position on a label that restates the tool name, then repeats "due diligence" a second time. Two of the three clauses are redundant, making the brevity less a virtue than a missed opportunity to convey scope.

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?

This tool has no annotations and no output schema, so the description must supply behavioral and return-value context — it supplies neither. It doesn't say what result the agent will receive, which sources are consulted, whether both parameters are expected, or how the result differs from domain-intel/domain-report/domain-audit. For a tool spanning three investigation areas, this is under-specified.

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 100%, so the baseline is 3 — the schema already documents "Host to process" and "Domain to process." The description adds nothing about the relationship between host and domain (alternatives vs. both required vs. precedence), but per the rubric the schema carries the parameter-documentation burden, so no penalty below baseline 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 the resource (domain) and lists three focus areas — ownership, reputation, risk — which is a step above pure tautology. However, "due diligence" is an abstract umbrella term: it doesn't state what operation is performed, what output is produced, or how this differs from siblings like x402-domain-intel, x402-domain-report, x402-domain-audit, or x402-whois. The opening label "Domain Due Diligence:" merely restates the tool name.

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?

No guidance is given on when to use this tool versus the many domain-related siblings (whois, domain-intel, domain-report, domain-audit, ssl-check, dns-lookup). The phrase "due diligence" only implies a vetting context; no alternatives, exclusions, or prerequisites are stated. With zero required parameters, the description also gives the agent no signal about what minimal input constitutes a valid call.

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