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

The description thoroughly explains the response structure, including all possible status values, the meaning of ends_at, and the interpretation of only_hobby. It also states that the tool takes no arguments, fully disclosing its behavior.

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 somewhat lengthy due to the embedded JSON and explanatory notes, but it is well organized and each part adds necessary detail. It could be more concise, but it remains efficient for conveying critical 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?

Given that there is no output schema, the description fully compensates by specifying the response shape and semantics. It covers all field meanings and edge cases, making it complete for an agent to understand the tool's output.

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 no parameters, and the description explicitly notes 'Takes no arguments.' This is sufficient and leaves no ambiguity about input expectations.

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 the tool returns the account's plan state and distinguishes it from site-level data. It explicitly mentions it is not about a site, making its purpose unambiguous.

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 does not explicitly state when to use this tool, but the clarification that it is 'not a site's' helps differentiate it from site-related tools in the sibling list. This implicitly guides selection, though it lacks an explicit 'use when' statement.

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