List databases

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description still adds genuine operational context the annotations cannot express: the meaning of an empty list and the retry-vs-restart behavior during an active download. It stops short of covering return format or any rate/pagination behavior, so a 4 rather than 5.

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?

Three short sentences with no filler. The primary use case is front-loaded in sentence one, and the failure/edge-case guidance follows in priority order.

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?

An output schema exists, so return values need no elaboration, and the description's summary of what is listed is sufficient. For a no-arg, read-only discovery tool with full annotation coverage, nothing an agent needs to call it correctly is missing.

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 takes zero parameters, so the baseline is 4 and there is nothing for the description to clarify about argument semantics. It correctly adds no redundant parameter prose.

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 verb and resource (list loaded databases) plus the payload it returns: metadata, download status, and setup instructions. It also positions itself against the siblings by being the prerequisite discovery step ('Call this first to choose exact database filenames for other tools'), so an agent can separate it from inspect_database, install_database, or verify_database without opening a schema.

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?

Gives explicit ordering guidance ('Call this first'), explains how to interpret an empty result (download may still be running), and prescribes the correct action when status is downloading (wait and re-call rather than kick off another update — implicitly steering away from install_database). Both when-to-use and when-not-to-act are covered.

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