threat_ip_to_domains

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It discloses the method (PTR and CT log searches) and the output scope ('all domains/subdomains'), which adds useful context. However, it does not mention potential limitations, data freshness, rate limits, or whether the query is performed in real-time, leaving some behavioral aspects undisclosed.

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 two sentences and 34 words, front-loaded with the main verb and purpose. Every sentence contributes meaning: the first explains the method, the second clarifies the output. There is no unnecessary fluff or repetition beyond a minor clarification.

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?

For a simple single-parameter lookup tool with no output schema, the description is complete. It states what the tool does, how it does it, and what it returns ('all domains/subdomains'). This is sufficient for an agent to understand the tool's functionality and expected output, especially given the minimal complexity.

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?

The input schema has 100% coverage, with the 'ip' parameter already described as 'The IP address to resolve to domains (e.g. '93.184.216.34')'. The description does not add extra meaning beyond the schema, such as IP format constraints or IPv4/IPv6 specifics, so it meets the baseline for schema coverage.

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 clearly states the tool resolves an IP address to all known domains and subdomains using reverse DNS (PTR records) and Certificate Transparency log searches. It uses a specific verb ('resolves') and resource ('IP address to domains'), and the combination of methods distinguishes it from siblings like dns_reverse and ct_search.

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?

The description implies a comprehensive IP-to-domain lookup combining reverse DNS and CT logs, but it does not explicitly state when to use it over alternatives such as threat_passive_dns or dns_reverse. There is no mention of exclusions or preferred contexts, leaving usage guidance implied rather than explicit.

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