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

Annotations already declare readOnlyHint=true and openWorldHint=true, indicating a safe read operation with variable output. The description complements this by specifying the exact record types returned, adding behavioral context beyond the annotations. It does not cover error handling or rate limits, but for a simple lookup tool, this is sufficient.

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 extremely concise: two sentences and a parameter definition. It front-loads the core action immediately and avoids unnecessary words. Every sentence is purposeful, making it easy for an agent to parse quickly.

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?

For a tool with one required parameter, readOnly and openWorld annotations, and no output schema, the description is fairly complete. It specifies the return content (record types). It could mention that it queries public DNS servers, but this is implicit. Overall, it covers the essential context without exceeding what's needed.

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?

With schema description coverage at 0%, the description carries the burden for parameter explanation. It adds 'Domain name (e.g. 'example.com')', which provides an example format and clarifies the expected input. While it doesn't delve into format constraints (e.g., no protocol), the single-parameter simplicity makes this adequate.

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 the tool looks up DNS records for a domain and lists the specific record types returned (A, AAAA, MX, CNAME, TXT). This provides a precise verb-resource combination, distinguishing it from other DNS-related tools like whois or SSL checks, though it doesn't explicitly differentiate from the sibling 'seo-web-analysis__check_dns'.

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 does not provide explicit guidance on when to use this tool versus alternatives. While it clearly indicates it is for DNS record lookups, it lacks context about when not to use it (e.g., for WHOIS or SSL) and does not name similar tools to avoid confusion. Given the presence of a similar sibling 'seo-web-analysis__check_dns', more differentiation would be helpful.

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