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

Annotations already establish this as a safe, read-only, idempotent operation, so the description does not need to cover safety. It adds useful behavioral context beyond annotations by specifying that the response includes a full model list sorted by input price, which helps the agent understand the tool's output characteristics.

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 a single, tightly written sentence with no filler. It front-loads the core purpose ('One gateway's profile') and packs the key return details and ordering behavior into an efficient structure.

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 one-parameter, read-only tool with strong annotations, the description covers the essential information: what the tool returns, what details are included, and the ordering. Nothing critical is missing for an agent to select and invoke this tool correctly.

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 describes the slug parameter as coming from list_gateways, and the description does not add much additional parameter meaning beyond that. With 100% schema description coverage, the schema carries the semantic weight, so a baseline of 3 is appropriate.

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: retrieving one gateway's profile plus its full model list, with details like prices, context length, modalities, and isFree. This clearly distinguishes get_gateway from list_gateways, which presumably lists gateways without full model details.

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 implies the primary use case: fetching a single gateway's detailed information by slug. It also points the agent to list_gateways as the source of the slug, giving a clear usage context. However, it does not explicitly name alternatives or state when not to use this tool.

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