List Carriers

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds nothing beyond that: no indication of whether the list is static reference data, whether it is paginated or filtered, or how carriers relate to the connections mentioned. For a simple read this is tolerable but it is pure restatement.

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 short sentence with the resource front-loaded and no wasted wording. It is efficient, though its brevity borders on under-specification rather than disciplined concision.

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 values need not be explained, and annotations cover the safety profile. However, for a discovery tool the description leaves open whether carriers are a fixed reference set and how they map onto routes, which is the main thing an agent would want before calling it.

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 is a single optional 'lang' parameter with 100% schema description coverage and an inline enum, so the schema fully documents it. The description mentions no parameter behavior at all, which is acceptable given the high coverage but adds no meaning beyond the schema baseline.

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 gives a specific verb and resource ('List carriers') plus a scope qualifier ('operating RegioJet connections'), so an agent knows exactly what is returned. It does not explicitly differentiate itself from the sibling list_* tools, but the resource noun is distinct enough that confusion is unlikely.

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: the description makes clear this is a reference enumeration of carriers, which an agent can infer is for discovering available carriers. There is no explicit when-to-use, no prerequisites, and no mention of alternatives such as search_routes when the real goal is route planning.

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