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

With no annotations, the description carries the full behavioral burden, and it delivers a genuinely useful negative scope statement: no live availability, schedules, or fares. That prevents a whole class of misuse. It stops short of covering notable traits such as what happens when a route is not found or whether any auth is required.

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 tight sentences: the lookup action and its keys come first, and the negative scope clause second. Every clause carries information and nothing is padded.

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 return shape need not be described, and the description covers the inputs and the scope boundary. The main omission is edge-case behavior for an unpublished or invalid route pair, which matters for a lookup tool but is not fatal here.

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 0%, so the description must compensate; it does explain that origin_iata and destination_iata are IATA codes, adding format meaning beyond the bare property names. The third parameter, locale (with its en/es enum), gets no mention at all, so the compensation is only partial.

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 verb ('look up') and resource ('published Cuba Te Espera charter route') keyed by origin and destination IATA codes, so the operation is unambiguous. It also implicitly distinguishes itself from search_published_charter_flights by stating it does not return schedules or fares, though it never names the sibling explicitly.

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?

Usage is only implied: an agent can infer this is metadata lookup rather than a search, and the 'never returns live availability, schedules, or fares' clause hints that those needs belong elsewhere. However, no alternative tool is named and no precondition ('only works for published routes') is spelled out.

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