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

No annotations are provided, so the description carries full responsibility for behavioral disclosure. It mentions using 'gravity ratios' but does not explain side effects, required permissions, or output format. Minimal transparency beyond basic purpose.

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 three sentences, each contributing some value: purpose, use cases, and a sibling reference. Slightly redundant with schema (parameter description), but overall concise.

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?

The description does not detail the return format despite an output schema being present. The discrepancy between 'each planet' and the required single planet parameter reduces completeness for a simple calculator 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?

Schema coverage is 100% with descriptions for both parameters. The description adds 'weight on Earth (kg)' which mirrors the schema's 'earth_weight_kg' description. It does not explain the enum values or planet selection, but schema already covers that.

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 'Compute your weight on other planets' using gravity ratios, which is specific. However, it says 'Returns weight on each planet' while the schema requires a single planet, causing ambiguity. Sibling context is clear as this tool is distinct among many calculators.

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 mentions use cases ('fun, education, sci-fi') and references related tools via list_bundles, but does not explicitly state when to use or not use this tool versus alternatives.

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