Get AWS Regions

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

Annotations already declare readOnlyHint=true (safe) and openWorldHint=false (fixed result set). The description adds the return structure (dictionary with success status and list), providing useful behavioral context beyond annotations. No contradictions.

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 extremely concise with two sentences, no filler, and front-loaded purpose. Every word earns its place, making it efficient for an agent to parse quickly.

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?

Given the tool has no parameters, annotations cover safety, and an output schema exists (implied return structure), the description is complete. It states exactly what the tool returns, leaving no gaps for an agent to misinterpret.

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 no parameters, so the description naturally adds nothing about them. Schema coverage is 100% (0 params). Baseline for 0 params is 4, and the description meets that without needing to compensate.

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 clearly states the action 'Get a list of available AWS regions'. It distinguishes from siblings like 'call_aws' (which makes API calls), 'suggest_aws_commands' (which suggests commands), and 'get_caller_identity' (which gets identity), making the purpose specific and unambiguous.

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?

While the description does not explicitly provide when-to-use or alternatives, the purpose is self-explanatory for a simple list retrieval tool. The context of siblings implies its role. A more explicit guideline would elevate this, but for a trivial tool, it is sufficient.

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