Search available numbers

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

Annotations already declare readOnly, idempotent, non-destructive. Description adds that it returns paginated candidates not owned, and that it searches upstream inventory. No contradictions. Still, does not detail pagination behavior or rate limits.

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?

Three sentences, no fluff, efficiently conveys purpose, usage, and alternatives. Front-loaded with key action.

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 11 optional params and no output schema, description provides essential context for usage and outcome. However, it does not describe the structure of returned candidates (e.g., fields like phone number, rate center, cost). Still, it sufficiently guides the agent.

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 has 100% coverage for all parameters. Description lists main search criteria (area code, rate center, locality, digit pattern) but adds no additional meaning beyond schema descriptions. 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 it searches upstream inventory for purchasable telephone numbers by various criteria, and distinguishes from sibling tools like num_list (for owned numbers) and num_order (for purchasing). Verb 'Search' and resource 'upstream inventory' are specific.

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?

Explicitly says 'Use this before ordering; then buy a candidate with num_order (or many with num_bulk_order). For numbers you already own use num_list.' Provides context and alternatives.

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