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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered structurally. The description adds a light behavioral note ('Returns: {direction, tips}'), but says nothing about the recovery model's assumptions (e.g. whether naps/melatonin are factored in) that would matter to an agent.

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?

Two short sentences, purpose front-loaded, no padding. The trailing 'See list_bundles' cross-reference is useful but slightly off-topic for the core statement.

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?

An output schema exists, so the return-values sentence is arguably redundant, but with one fully documented parameter and complete annotations the definition gives an agent everything needed to invoke it correctly. Only the model's underlying assumptions remain unstated.

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 there is only one parameter, whose description already explains the sign convention (positive = eastward, negative = westward) and the -12..14 bound. The description restates the parameter's meaning without adding format or edge-case detail, so the baseline 3 is appropriate.

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?

States a specific verb and resource: 'Estimate jet lag recovery time', with the input basis (timezone difference and direction of travel). No sibling shares this purpose, so differentiation is moot rather than missing, but the description does not explicitly anchor itself against nearby time/sleep tools (calculate_sleep_cycles, calculate_timezone_convert).

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?

'See list_bundles for related voyage calculators' points at a discovery path but gives no when-to-use vs when-not guidance and names no true alternative for this task. Usage is implied by the purpose statement rather than stated.

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