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

With no annotations, the description carries the behavioral burden and does well: it lists common TelcoData return fields and explains the thousands value semantics, including -1 as default aggregate and 0-9 as pooling blocks. It does not cover auth behavior, pagination, or error conditions, so it is not fully complete.

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 front-loaded with purpose and examples, then adds only relevant caveats and return-field context. Sentences are dense but each contributes useful selection or interpretation guidance.

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?

Because there is no output schema, the description appropriately compensates by naming common returned fields and explaining thousands semantics. It covers enough for correct invocation, though pagination and response shape are not described.

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 schema already documents all four parameters. The description still adds useful meaning by clarifying that rate-center names are telecom labels rather than necessarily postal cities and by emphasizing include_blocks=true for pooling detail.

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 specific verb/resource pair: search exchanges/prefixes for a rate center, scoped by state/province/NANP country code. It also distinguishes telecom rate-center geography from postal-city geography and gives concrete examples, which helps separate it from geocode-style siblings.

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 clearly states when to use the tool, including example local-service geography questions, and notes that rate-center names may differ from postal city names. It does not explicitly name sibling alternatives or when-not-to-use cases, so it falls short of full routing guidance.

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