dns_lookup

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

With no annotations provided, the description carries the full burden. It discloses the tool's behavior by specifying the types of DNS records returned and the server querying aspect. However, it lacks details on rate limits, error handling, or response format, which are important for a network tool. The description does not contradict any annotations, as none exist.

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 sentences that are front-loaded with the core purpose and efficiently detail the parameters and server behavior. Every word contributes to understanding the tool's functionality without redundancy or unnecessary elaboration.

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, the description adequately covers the tool's purpose and parameters. However, as a network query tool, it lacks details on output structure, potential errors, or performance considerations, which would be helpful for an agent. It meets minimum viability but has gaps in 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 value by clarifying the scope of DNS records (listing A, AAAA, etc.) and explaining the 'server' parameter's default and the 'authoritative' option, which enhances understanding beyond the schema's enum list. This elevates the score to 4.

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 action ('look up'), the resource ('DNS records'), and specifies the scope ('all common DNS records: A, AAAA, NS, MX, TXT, CNAME, SOA'). It distinguishes itself from siblings like dns_propagation or dns_record by emphasizing comprehensive record retrieval rather than specific checks or single-record operations.

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 usage for DNS queries with server options, but it does not explicitly state when to use this tool versus alternatives like dns_record or dns_propagation. It mentions a default server and the 'authoritative' option, which provides some context, but lacks clear guidance on tool selection among siblings.

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