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

While annotations handle the safety profile (readOnlyHint), the description adds valuable context about the data's freshness and methodology ('using the same 2026 benchmark model'), managing user expectations about the result's accuracy.

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 perfectly structured, using two concise sentences to cover the functionality and the crucial limitations/prerequisites efficiently.

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 the 100% schema coverage and the strong set of annotations, the description provides all the high-level behavioral constraints and contextual warnings an agent needs to correctly select and use the 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?

The schema requires slugs, and the description reinforces this by explicitly warning the user about the input quality needed ('not a guessed display name') and providing a call to action ('Resolve exact city slugs first'). This adds necessary contextual meaning to the required string 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 purpose is clear: to 'Estimate charter costs.' While it doesn't name a direct pricing sibling to distinguish it from, for example, a 'get_live_price' tool, the description establishes its function and scope well.

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 provides critical usage guidelines by stating it is 'Not a live quotation or flight plan.' It also dictates a necessary prerequisite action: 'Resolve exact city slugs first,' preventing common input errors.

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