enable_default_key_replication_regions

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It discloses the account-level scope, the non-retroactive behavior, and the side effect on subsequently created keys. However, it does not mention response behavior or permission requirements, though those are less critical for this additive configuration operation.

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 tight and front-loaded: it immediately states the action, then scope, then the sibling alternative, then the argument. Every sentence earns its place without extraneous detail.

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 single-parameter configuration tool, the description covers the key operational context: what the tool does, its account-level scope, its non-retroactive behavior, and the alternative for existing keys. It does not describe the response format, but no output schema exists and the missing detail is unlikely to prevent correct invocation.

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 description coverage is 0%, so the description must compensate. It explains that replication_regions are 'Regions to enable by default' and provides a concrete example, i.e. ['us-west-2']. This gives an agent enough meaning to supply the parameter, though region validation rules are not stated.

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: 'add regions to the account-wide default' so that subsequently created keys replicate there automatically. It clearly distinguishes this from add_key_replication_regions by noting it affects future keys only.

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 use this tool ('account-level', 'future keys only') and names the alternative for existing keys: 'Use add_key_replication_regions for keys that already exist.' It also clarifies that it does not retroactively replicate existing keys, which prevents misuse.

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