vpc_update

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

With no annotations provided, the description must disclose behavior, but it only mentions returning a success confirmation. It does not state whether the operation is idempotent, whether it requires special permissions, or the impact on dependent resources. The behavior is implied as a simple update, but the description carries the full burden and falls short.

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, with a clear heading and a single sentence stating the purpose, followed by a bulleted argument list and a Returns line. It is appropriately front-loaded with the core purpose. No wasted words, though the argument list is somewhat redundant with the schema.

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?

The output schema exists, so the description need not explain return values in detail. The tool is simple with only two parametersable coverage is minimal but adequate for the simplicity. However, given no annotations and an output schema that may not be self-explanatory, the description could be stronger on prerequisites and side effects, making it minimally viable but not complete.

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 does explain that vpc_identifier can be a description or ID and that description is the new value, which adds meaning beyond the raw schema. However, it does not clarify the format or constraints of the description field (e.g., length, charset), leaving some ambiguity. Baseline 3 is appropriate given partial compensation.

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 ('Update VPC description') and the resource (VPC), and mentions smart identifier resolution. It distinguishes itself from the vpc_update_vpc2 sibling by focusing on the description update, though the distinction is implicit rather than explicit.

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 provides no guidance on when to use this tool versus alternatives like vpc_update_vpc2 or vpc_attach_to_instance. It does not specify prerequisites (e.g., whether the VPC must exist or be in a certain state) or explicit exclusions. The 'Smart identifier resolution' hint is useful but not sufficient to route the agent effectively.

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