My public IP

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

Beyond the readOnlyHint annotation, the description discloses an important nuance: the IP is from Shodan's perspective ('Shodan sees'), not necessarily the local machine's IP. This adds context about the tool's behavior and helps set expectations for the returned value.

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, no filler. The first sentence states the core function, and the second provides usage context. Every word earns its place, and the structure is front-loaded with the key verb.

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 read-only, zero-parameter tool with no output schema, the description is complete. It explains what the tool returns, the source of the IP, and a recommended use case. No additional information is necessary for an agent to select and invoke it 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?

The tool has zero parameters, so the schema covers 100% of the parameter space. The description adds semantic meaning by explaining what the output represents, which is more valuable than a bare schema. Since there are no parameters, a baseline of 4 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 action: 'Returns the public IP address Shodan sees this API key's requests coming from.' This is a specific verb+resource (returns public IP) and distinguishes itself from sibling tools that handle CVEs, DNS, host lookup, and search.

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?

It provides a clear use case: 'Use this as the starting point for scanning your own infrastructure.' This gives the agent context for when to invoke it, though it doesn't explicitly mention alternatives or when-not-to-use. The guidance is sufficient for a simple tool.

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