infra_open_resolver

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

No annotations are provided, so the description carries the full burden. It explains the core behavior (testing for recursive queries from any source and checking EDNS0 buffer size) and the security implication. However, it does not disclose potential side effects (e.g., sending network traffic), expected output format, or any prerequisites. The description adds meaningful context but lacks some behavioral details.

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 exactly two sentences, both front-loaded with the primary action and key details. No wasted words; every sentence contributes to understanding purpose and additional checks.

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 simple one-parameter tool with no output schema, the description covers the primary function, the security rationale, and an additional check (EDNS0). It is slightly incomplete because it does not describe the return value or result format, but given the tool's simplicity and the lack of complex nested objects, it is largely 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 coverage is 100% and the parameter description ('IP address or hostname of the DNS nameserver to test') is already self-explanatory. The tool description does not add additional semantic meaning beyond the schema, so baseline 3 is appropriate.

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's function: 'Test if a DNS nameserver is an open resolver' and provides a precise definition. The mention of 'DDoS amplification attacks' and 'EDNS0 buffer size from OPT record' adds specificity that distinguishes it from sibling tools like infra_amplification or dns_recursive_check.

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 clearly implies when to use this tool: when you need to determine if a DNS nameserver is open to recursive queries. It does not explicitly mention alternatives or exclusions, but the context is clear enough for an agent to select this tool over similar infrastructure checks.

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