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

With no annotations, the description carries the full burden and discloses key behaviors: it uses DoH, returns clean JSON, and costs $0.005 per call paid via x402. It does not mention error behavior (e.g., NXDOMAIN) or rate limits, but for a simple read-only lookup, the provided information is substantial.

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 three concise sentences with no fluff. It front-loads the core purpose, then adds output format and pricing. Every sentence 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 the tool's simplicity (2 parameters, no output schema), the description covers the essential aspects: what it does, how it returns data, and cost. It omits error handling and response structure details, but for a DNS lookup with clean JSON, this is a reasonable level of completeness.

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 100%, so the baseline is 3. The description adds a general note about 'common record types' but does not enrich the parameter meanings beyond what the schema already provides. No extra syntax or format details are given.

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+resource ('DNS lookup over DoH') and distinguishes itself from sibling tools (erdap, lei, qr, etc.) by clearly stating it resolves DNS records. The mention of common record types and clean JSON further clarifies scope.

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 the tool (for DNS resolution) and provides clear context about the output format and payment. It does not explicitly name alternatives or exclusions, but the tool is clearly differentiated by its DNS-specific function.

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