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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description does not need to re-state safety. The description adds useful behavioral context by specifying that the tool returns a bounded set of 3-5 destination suggestions. It does not go deeper into response formatting or any limitations, but for a read-only suggestion tool this is adequate.

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 two sentences with no filler. The core behavior and example are front-loaded, and the usage context immediately follows. Every sentence earns its place.

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 one-parameter tool with a full schema, an output schema, and safety annotations, the description is complete. It tells the agent what to produce, gives an example input, and states the decision-relevant usage context relative to other tools.

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 already documents the single 'mood' parameter at 100% coverage, so the baseline is 3. The description adds value beyond the schema by providing a rich example ('somewhere warm in November, food-first') that clarifies the parameter can express compound, multi-constraint trips in plain language.

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 the action ('Suggest 3-5 destinations'), the input ('trip mood or constraint set'), and provides a concrete example. The phrase 'Use when the traveller has not settled on a place yet' also distinguishes it from sibling tools like destination_brief or top_spots, which are more relevant after a place is chosen.

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 explicitly states when to use the tool: when the traveller has not settled on a place yet. It does not explicitly name alternatives or describe when not to use it, but the guidance is clear enough to route an agent correctly in most cases.

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