Reverse DNS (PTR)

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, so the description adds limited behavioral detail beyond confirming it returns errors. It doesn't contradict annotations, but adds little extra transparency.

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 structured with clear sections (Args, Returns, Example, Errors) and is concise. It front-loads the main action but could be slightly tighter without losing clarity.

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 annotations (read-only, non-destructive) and existing output schema, the description covers all essential aspects: purpose, parameters, return format, example usage, and error conditions. It is fully adequate for an agent to select and invoke the tool correctly.

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% with clear descriptions. The description adds an example and error handling context, which enriches understanding beyond the schema alone. The baseline of 3 is exceeded due to this added value.

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 resolves PTR records for an IP address, returning the hostname(s) the IP maps back to. This distinguishes it from forward DNS lookups and sibling tools like dns_lookup, making the purpose explicit.

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 includes an example query and mentions error cases for invalid IP or no PTR record, guiding usage. However, it does not explicitly contrast with sibling tools or specify when not to use it, but the unique purpose reduces ambiguity.

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