break_even

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

Since no annotations are provided, the description carries the full burden of behavioral disclosure. It does explain the result interpretation (below/above threshold), but lacks details on underlying pricing assumptions, computation side effects, or any state changes. For a calculation tool, this is minimally adequate but not rich.

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, well-structured sentence that states the core function and its result interpretation with zero unnecessary words.

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 calculation tool with no output schema, the description adequately conveys the purpose and the meaning of the result. However, it does not detail the response format or specify when to choose this over sibling tools, leaving a minor gap in context.

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 100%, and each parameter has a clear description with defaults and ranges. The tool description adds no extra parameter-specific meaning, but the schema already handles this dimension, warranting the baseline score of 3.

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 uses a specific verb 'Find' and clearly identifies the resource: 'daily usage hours at which API cost equals a subscription price'. It distinctly differentiates from siblings like compare_plans and recommend_plan by focusing on the break-even threshold calculation.

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?

No guidance on when to use this tool versus the listed siblings (compare_plans, run_scenario, recommend_plan). The description explains the threshold outcome but omits any exclusions or alternative tool references, leaving the agent to infer usage context.

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