start_key_usage

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

There are no annotations, so the description carries the behavioral disclosure burden. It does disclose the core behavior — changing a key from disabled to active — but it does not mention permissions, reversibility, idempotency, or any side effects. This is adequate but not richly transparent.

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 short and front-loaded, but the second sentence ('Activate a key that was created in disabled state') largely repeats the first sentence's trigger condition. The Args section is useful, but one sentence is redundant.

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 single-parameter tool with no output schema, the description covers the key use case and parameter semantics well. It lacks only minor details like permissions and exact API behavior, which are not critical given the tool's low complexity.

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 input schema only says key_identifier is a string, but the description adds important meaning by specifying it accepts a key ARN or alias. This compensates for the 0% schema description coverage, though it could be even more explicit about accepted alias formats.

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 action — enabling or activating a key — and distinguishes this tool from siblings like stop_key_usage and create_key. It clearly identifies the resource and the state transition involved.

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 explicitly says when to call it: when enabling a key created with enabled=False or one previously disabled with stop_key_usage. It gives clear context, though it does not explicitly list when not to use it or name all alternatives.

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