List databases

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

Annotations already declare this as read-only, idempotent, non-destructive, and open-world, which covers the safety profile. The description adds the behavioral detail that the result includes database engines, which is useful context beyond the annotations for a zero-parameter read 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 a single, six-word sentence that front-loads the action and resource while adding the one meaningful extra detail ('engines'). There is no wasted text or redundant phrasing.

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 simple, parameterless read-only operation, the description plus annotations provide everything an agent needs: what is listed, what fields are returned, and the safety characteristics. No output schema exists, but the description sufficiently indicates the return content.

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?

There are zero parameters and the input schema fully documents this fact, so the description does not need to add any parameter-related information. Per the baseline for zero-parameter tools, this is appropriately handled.

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 names a specific verb ('List'), a clear resource ('databases'), and an additional detail ('their engines'), which precisely identifies what the tool does. It is immediately distinguishable from sibling tools like list_tables or describe_table because it targets databases as the resource.

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 intended use is implied by the verb-resource pairing, so an agent can infer this is the tool to call when it needs to enumerate databases. However, the description provides no explicit when-to-use guidance and does not mention alternatives or exclusions, so it falls short of clearer context.

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