lookup_dns

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

No annotations provided, but description declares read-only, explains use of DNS-over-HTTPS, and mentions return fields. Lacks explicit error handling behavior (e.g., NXDOMAIN), but overall transparent.

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?

Two sentences, front-loaded key purpose and return format. No fluff, every sentence adds value.

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 no annotations and no output schema, description covers purpose, usage, default parameters, return content, and sibling differentiation. Lacks error handling details but is sufficient for a read-only lookup tool.

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 coverage is 100%. Description adds critical context: 'Pass `type` for a single record type or `types` for an array; if both omitted, returns A records.' This clarifies default behavior and the relationship between type and types.

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' and specifies return content. It distinguishes from siblings 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?

Explicitly says 'Use for arbitrary record queries' and provides alternatives 'use validate_dnssec for full DNSSEC chain validation, or check_dns_propagation for multi-resolver consensus.' Also notes no auth/rate limits.

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