Check DNS Records

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

No annotations are provided, so the description bears the full burden. It does disclose that the lookup is 'live' (no cache) and which record types are queried, which is useful. However, it does not describe behavior such as error handling, response format, or whether it follows CNAME chains, leaving some ambiguity for an agent.

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 with no filler. The primary action is front-loaded, and the use-case context is tucked into the second sentence. Every word 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?

The tool is simple with two well-documented parameters, but there is no output schema and the description does not mention what the return data looks like (e.g., TTLs, resolved IPs, or a formatted record list). An agent might need to discover the output shape at runtime, so the definition is adequate but not fully complete.

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%: both 'domain' and 'recordType' have descriptions, and recordType has an enum. The description adds no extra parameter-level meaning beyond the schema, so it meets but does not exceed the baseline.

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 ('Looks up'), names the resource ('DNS records'), and enumerates the record types (A, AAAA, CNAME, MX, TXT, NS). This clearly distinguishes check_dns from sibling tools like check_http_status, check_ssl, and check_security_headers, which target different aspects of a domain.

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 second sentence explicitly states when to use this tool: 'diagnose propagation delays, missing records, or misconfigured mail/DNS setups.' This provides clear context but does not mention when not to use it or name alternative tools, so it stops short of a 5.

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