dns_lookup

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

With no annotations provided, the description carries the full burden of disclosing behavior. It mentions supported modes (resolve, reverse, propagation) and record types, which gives some operational context. However, it does not discuss safety (e.g., read-only nature), error behavior, or rate limits, so it only partially fills the gap.

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: the first states the core action and record types, the second mentions supplementary capabilities. Every word earns its place; it is front-loaded and free of filler.

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?

The description is adequate for a read-only lookup tool with a simple schema. It explains the primary purpose and the alternative modes, giving enough context for an agent to select the tool. It does not describe the output shape, but 'resolve to DNS records' implies the return value sufficiently for most use cases.

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 schema provides 100% coverage of all three parameters, including descriptions and enums. The tool description adds no substantive information beyond what the schema already contains (e.g., record types are listed in both). Baseline 3 applies because the schema handles the semantics.

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 a specific verb ('Resolve') and resource ('domain name to DNS records'), enumerating record types. This distinguishes it from sibling tools like ip_info, whois_lookup, and ssl_check, which serve different purposes.

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 makes the tool's use-case obvious: use it for DNS resolution, reverse DNS, or propagation checking. It does not explicitly name alternatives or exclusions, but the context is clear and uncluttered by unrelated functionality.

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