add_key_replication_regions

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

No annotations are present, so the description carries the burden. It discloses that replication copies the key for cryptographic serving, explicitly states no key material is exported, keeps the key within APC HSMs, and preserves ARN semantics and usage restrictions. It does not mention permissions, latency, or confirmation behavior.

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 front-loaded with purpose, followed by a tightly scoped behavioral note and a compact Args section. Every sentence adds value, and the examples are minimal and clear.

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?

With no annotations and no output schema, the description covers purpose, usage context, behavioral implications, and both parameters. It is missing operational expectations such as response shape, whether replication is synchronous, and any prerequisites, but overall it is strong.

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%, and the description compensates by explaining key_identifier accepts an ARN or alias and replication_regions takes a list of region codes with a concrete example. It could add constraints like allowed region values or limits, but the core meaning is clearly conveyed.

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?

States a specific action: making an existing key usable from additional regions via replication. The DR and processor-proximity examples clarify intent, and the description clearly distinguishes this from create/remove operations.

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?

Provides concrete scenarios for use (DR region, moving workload closer to processor) and clarifies the key must already exist. It does not explicitly list exclusions or alternatives like remove_key_replication_regions, so it stops short of a 5.

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