List Plans

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

With no annotations, the description carries the full behavioral burden. It adds useful context that plans returned are REAL and currently purchasable, not stale or hypothetical, and that codes/prices are exact. However, it does not disclose whether the operation is read-only, whether any auth is needed, or any other side effects.

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 a single, front-loaded sentence followed by a short workflow directive. Every word earns its place, and the core purpose is immediately visible.

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 simple 2-parameter tool this is adequate, and the pay_bill prerequisite adds workflow context. However, there is no output schema and the description does not explain the return structure beyond 'exact codes and current prices,' and the provider parameter remains undocumented, leaving the tool somewhat incomplete.

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 description coverage is 0%, so the description must compensate, but it only covers the service parameter by naming the three enum values. The provider parameter is completely unexplained, including its format or whether it corresponds to a listed provider. This is a meaningful gap for an agent trying to invoke the tool correctly.

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 (List) and resource (real, currently purchasable plans) with an explicit service scope (DATA, CABLE, EDUCATION) and promises exact codes and current prices. This clearly distinguishes it from sibling tools like list_international_options, so an agent can identify what this tool is for.

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 explicitly tells the agent to always call this tool before pay_bill for these three services, which is strong contextual guidance. It does not spell out when not to use it or name alternative tools, but the workflow dependency is clearly stated.

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