get_key

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

With no annotations, the description carries the full burden for behavioral disclosure. 'Retrieve metadata' clearly implies a read-only operation, and listing the metadata fields gives useful context about what the tool exposes. It does not explicitly state that no mutation occurs or describe permission requirements, but for a getter tool the side-effect profile is clear.

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 concise, front-loaded with the use case, and contains no filler. The three short sections—when to call, what it does, and the parameter format—each earn their 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 simple one-parameter getter with no output schema and no annotations, the description covers when to use it, what metadata is returned, and how to identify the key. It could add a brief note on return shape or explicitly distinguish itself from sibling getters, but nothing critical is missing.

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 coverage is 0%, so the description must compensate, and it does. The Args section explains that key_identifier accepts a full ARN (arn:aws:payment-cryptography:...) or an alias (alias/name), which is exactly the information an agent needs beyond knowing the parameter is a string.

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 ('Retrieve metadata'), a clear resource (a key), and the lookup method (by ARN or alias). It also lists the metadata dimensions (state, algorithm, usage, enabled status), which clearly differentiates it from get_alias and list_keys.

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 first sentence explicitly states when to call the tool: when you need the key's current state, algorithm, usage, or enabled status before using it in an operation. It does not explicitly name sibling alternatives or state when not to use it, so there is a small exclusion gap.

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