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

No annotations are provided, so the description must carry behavioral information. It usefully discloses that missing inputs fall back to documented defaults and indicates that cost figures are computed. However, it does not state whether the operation is read-only, whether any state changes occur, or what the returned result structure is.

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 sentence that front-loads the action and then lists the relevant calculated metrics without padding. The semicolon list is a little ambiguous about whether items are inputs or outputs, but overall the description is economical and appropriately sized.

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 nine-input tool with no output schema and no annotations, the description supplies only a terse list of possible outputs and the default-fallback behavior. It does not explain the ownership-crossover result, the output format, or how inputs map to outputs, leaving some interpretation gaps even though the schema fully documents the parameters.

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?

The input schema has full coverage with descriptions and defaults for all nine parameters, so the description does not need to re-explain them. The description adds high-level context about outputs but no parameter-specific semantics, formulas, or mappings beyond what the schema already provides.

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 names a specific action ('Run') and a specific resource (the Charter cost and ownership crossover calculator), and it lists the figures the calculator produces. It is clearly distinct from calculator_describe, though it does not explicitly contrast itself with any sibling.

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 intended use is implied: this tool executes the calculator, while calculator_describe likely describes it. However, there is no explicit when-to-use or when-not-to-use guidance, no stated alternatives, and no mention of conditions that would make a sibling tool more appropriate.

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