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

Annotations already establish readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuinely new behavioral context: this returns static published class listings and guidance, deliberately excluding live availability and confirmed prices, which tells the agent what answers it cannot get here. Return shape and any pagination are not described, keeping it below 5.

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?

A single tight sentence with no filler, and the resource scope is front-loaded ahead of the data limitations. It is a fragment rather than a verb-led statement, which slightly weakens immediate readability.

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 zero-parameter read-only listing tool with no output schema, the agent needs to know what data is present and what is absent, and the description supplies exactly that. A brief note on the fields returned would make it fully self-sufficient.

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?

There are zero input parameters, so the baseline is 4. The description introduces no parameter concepts, and none are needed for a no-argument listing tool.

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 resource set — published Vietnam charter coach classes plus passenger/luggage guidance — which is clearly distinct from the sibling tools get_quote_instructions and list_private_cars. The verb is only implied (it reads as a noun phrase, 'Published ... classes'), so it stops short of the 5 mark, but no agent would confuse it with a quote or private-car tool.

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 clause 'no availability or confirmed prices' gives a useful when-not-to-use boundary that implicitly pushes availability/pricing questions toward get_quote_instructions. However, the sibling is never named explicitly, and there is no positive statement of when this tool is the right choice versus alternatives.

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