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

With no annotations, the description carries full burden and does well: it discloses that it returns names only, never secrets, is safe to call freely, and explicitly warns that listing is not authorization. This fully covers the behavioral expectations for a read-only discovery tool.

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?

Though a bit detailed, every sentence adds unique value: purpose, return format, usage instruction with warning, safety, authorization caveat, and no-args note. There is no filler or redundancy, and the important warnings are clearly emphasized.

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 zero-parameter tool with no output schema, the description is complete: it explains what is returned ('capabilities' names), how to use the result (pass to pull_capability), safety aspects, and the critical authorization boundary. No gaps remain for an agent to misuse the tool.

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, and the description explicitly states 'Takes no arguments.' This aligns with the baseline for zero-param tools and reinforces what the empty schema already implies. No additional parameter explanation is needed.

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 a specific verb and resource: 'List the provider API keys your owner has stored in their Vault.' It explicitly distinguishes itself from pull_capability by noting it returns names only, not secrets, and from list_api_keys by specifying Vault and provider context.

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 explicit when-to-use (discover available keys) and how-to-use (pass names verbatim to pull_capability). Warns against guessing or normalizing names, and clearly states that discovery is not authorization—only use keys when the owner directs. Also notes the tool takes no arguments.

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