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 does reveal that the tool aggregates multiple record types in a single request, which is useful. However, it does not mention potential limitations such as missing record types, timeouts, rate limits, or the exact response format. This is a gap but not a severe one for a simple DNS lookup tool.

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 concise clauses with zero filler. It front-loads the action and scope, then provides the comparison to the sibling via a dash. Every word 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?

Given this is a simple one-parameter tool with no output schema and no annotations, the description covers the core purpose and identifies the alternative. It does not discuss error handling or edge cases, but for a read-only DNS lookup tool, the essential context is present. A 4 is justified because it is nearly complete, missing only minor non-essential details.

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 0%, so the description must compensate. The only parameter is 'domain,' and the description explains that it is the domain for which records are collected. This adds some meaning beyond the bare schema (type string, title 'Domain'). However, it does not clarify format expectations (e.g., whether protocol/subdomain is accepted), but domain is a familiar concept, so a 3 is appropriate.

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 uses a specific verb ('Collect') with a clear resource ('ALL common DNS record types') and enumerates the exact types (A/AAAA/MX/NS/TXT/CAA). It also differentiates itself from the sibling get_dns_lookup by framing itself as the 'multi-record bundle version.' This leaves no ambiguity about what the tool does.

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 when to use this tool: when you need multiple DNS record types in one call, as opposed to a single-record lookup. It explicitly references '/dns/lookup' as the alternative, which is a sibling. However, it does not explicitly state when not to use it (e.g., when only one record type is needed), so it falls short of a 5.

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