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

Annotations already mark the operation as read-only, idempotent, and non-destructive. The description adds meaningful context beyond those annotations by limiting results to the current user's vaults and indicating the output shape, which helps the agent set expectations.

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?

A single, front-loaded sentence states the action, scope, and returned fields with no filler. Every phrase adds information, making it efficient and easy for an agent to parse quickly.

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 parameterless list operation with a rich output schema and strong annotations, the description is complete. It covers what is listed, whose vaults are included, and what fields will be returned; no additional operational details are needed.

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 tool has zero parameters, so the description has no parameter burden to carry. The baseline of 4 applies, and the description appropriately focuses on scope and output without introducing any parameter confusion.

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 uses a specific verb ('List') and resource ('vaults') and explicitly scopes to 'vaults owned by the current user,' which differentiates it from sibling tools like set_vault. Naming the returned fields (IDs, names, descriptions) further clarifies exactly what the tool produces.

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 implies the tool is for discovering available vaults, especially given the sibling set_vault, but it does not explicitly state when to use this tool versus alternatives or mention any prerequisites. For a simple, zero-parameter listing tool this is adequate but not explicit.

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