get_billing_plan

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

Since there are no annotations, the description must provide rich behavioral context. It successfully discloses the key structural components of the returned data (tier, end date, limits, usage), which is crucial for an agent deciding how to interpret the final result.

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 single sentence is highly efficient. It front-loads the action (Get the detailed billing plan) and immediately follows with the specific, differentiating features it includes.

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 that there is no output schema, describing the key data fields (tier, subscription period end date, limits, usage) makes this description maximally complete for a 0-parameter tool.

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?

There are zero input parameters, and the input schema coverage is 100%. Therefore, the baseline score of 4 is appropriate as the description adds no semantic information regarding parameters.

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 that the tool retrieves the detailed billing plan, naming specific required components like tier, end date, and limits. While the function name suggests its purpose, the description adds scope by defining *what* 'detailed' means here.

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 implies when to use the tool (when needing detailed plan components). However, it provides no explicit guidance on when *not* to use it, nor does it clearly distinguish this from related tools like get_subscription, relying only on the content list.

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