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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful workflow transparency by revealing that processing is resumable via lookupId and that candidate/unit clarification may be required. It does not cover failure or error behavior, but the annotations reduce the need for that detail.

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 three sentences with no filler. The core purpose is front-loaded, and the workflow instructions are compact and easy to parse. Every sentence contributes necessary information.

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 output schema already covers return values, and the annotations cover safety and idempotency. The description covers the invocation sequence and clarification flow, including important 'alone' qualifiers. Together, the structured metadata and description are sufficient for an agent to call this 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%, so the baseline is 3. The description adds value by tying each parameter to a workflow stage: address starts the process, lookupId resumes it, candidateId continues clarification, and unit refines candidate clarification. This is more semantically useful than the schema descriptions alone.

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 states a concrete verb and resource: 'Resolve a U.S. street address or apartment and return internet providers and ISPs...' It also names the specific outputs—broadband, fiber, cable plans, speeds, and pricing—so the tool's purpose is unmistakable. Even with no sibling tools, an agent can tell exactly what this tool does.

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 gives an explicit invocation workflow: 'Start with address,' 'Pass lookupId alone to resume processing,' and 'Continue clarification with candidateId alone, or candidateId with unit when requested.' This tells the agent exactly which parameter to use at each stage and which combinations are appropriate.

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