list_databases

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

No annotations are present, so the description must indicate safety. The verb 'List' clearly implies a read-only operation, and 'connected MongoDB instance' provides useful context about the connection state. However, it doesn't explicitly confirm no side effects or state any permissions, but such omissions are minor for a listing 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, concise sentence that front-loads the verb and includes only essential information. There is no wasted wording or redundancy.

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?

With no output schema, the description should clarify what the tool returns. It only states the action ('List all databases') but does not specify the format or structure of the returned data (e.g., array of names vs. objects). For a simple read-only tool this is a minor gap, but it is still a gap.

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 baseline score is 4. The description doesn't need to add parameter info, and the empty schema is consistent. The phrase 'all databases' reinforces that there are no filters, which indirectly aligns with the lack of parameters.

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 the action ('List') and the specific resource ('all databases') with a scope ('on the connected MongoDB instance'). This distinguishes it from siblings like list_collections and list_indexes, which operate on different levels.

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 usage for enumerating databases but does not explicitly state when to prefer this tool over alternatives or provide any usage context. No exclusions or alternative tool names are mentioned, leaving the agent to infer based on the name.

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