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

With no annotations, the description carries the full burden of behavioral disclosure. It adds useful context about data currency and scope, but it does not state whether the operation is read-only, whether permissions are needed, or how invalid route ids are handled. The provided context is helpful but not comprehensive.

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 tight sentences with no filler. The core action, example, data scope, and exclusions are all front-loaded and each 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 tool with no annotations, no output schema, and two parameters (one undocumented in any way), the description leaves important gaps: parameter semantics are mostly unexplained, return shape is not described, and no guidance is given for choosing between this and sibling tools. The data-scope caveats help, but the agent is still under-informed.

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%, and the description does not compensate. It only gives an example route id ('OTP-BCN'), hinting at format, but it never explains the required route_id semantics or the meaning of include_charter, which is a non-obvious boolean flag that an agent would likely have to guess about.

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 states a specific verb and resource: 'Detail for one route' and lists what is included (airlines, schedule, seasonality) with a concrete example. It is conceptually distinct from the sibling tools (airport_destinations, find_connections, resolve_airport), but it does not explicitly name or differentiate them, so it stops short of a 5.

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 gives clear context about the data scope ('scheduled passenger routes operating now, with seasonality labels') and explicit exclusions ('not fares, not booking, not date-specific schedules'). This tells an agent what the tool is not for, though it does not name alternative tools for those cases.

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