lookup_dns

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

The description aligns with the annotations (read-only, idempotent, non-destructive) and adds context about the return format and the default behavior (returns A records if types omitted). No negative side effects are mentioned, and the tool is transparent about its operation.

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 concise, with no redundant information. It manages to convey the purpose, usage, output, and alternatives in just a few sentences, making it efficient for an agent to parse.

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 complete for a lookup tool: it covers what the tool does, the input parameters (with defaults), the output format, and how to choose between this and related tools. It also mentions operational details like the use of DoH and lack of rate limits, providing sufficient context for an agent.

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 already provides clear descriptions for each parameter, and the description adds the default behavior (A records when both type and types are omitted) and clarifies the distinction between single and multiple types. This fully covers parameter 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 it is a read-only DNS record lookup via DNS-over-HTTPS, specifies the output (parsed answers with TTL, rdata, AD bit), and distinguishes it from related tools like validate_dnssec and check_dns_propagation.

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 explicitly says 'Use for arbitrary record queries' and contrasts with alternatives: 'use validate_dnssec for full DNSSEC chain validation, or check_dns_propagation for multi-resolver consensus.' It also notes there is no auth or rate limits.

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