List databases

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

Annotations already declare readOnlyHint, idempotentHint, and closed-world access, so the safety profile is covered. The description adds genuinely non-obvious behavior: an empty list may mean a download is in flight, and a 'downloading' status means wait-and-repoll rather than triggering another update. Lacks any note on list size or staleness, so not a 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 sentences, each doing distinct work: what it returns, when to call it, and how to interpret an anomalous result. Front-loaded with the call-first instruction and free of repetition.

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?

A zero-parameter, read-only discovery tool with full annotation coverage and an output schema; the description covers the only real ambiguities (empty result, downloading status). 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 there is nothing for the description to disambiguate; baseline is 4. The description correctly implies the tool is unfiltered and takes no input to narrow results.

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') and enumerates what comes back: metadata, download status, setup instructions. It is clearly separable from siblings like inspect_database or install_database, which operate on a single already-chosen database.

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 an explicit ordering rule ('Call this first to choose exact database filenames for other tools') that routes the agent before it reaches inspect/verify/compare. It also covers the edge case where an empty list is expected, though it does not explicitly name which sibling to invoke next.

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