list-databases

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

The annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows this is a safe read operation. The description adds minimal behavioral context beyond the annotations, such as no mention of pagination or return format. This meets the baseline but does not provide extra value beyond what the annotations already convey.

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 is front-loaded with the verb 'List' and directly states the action and resource. Every word is meaningful, with no redundancy or filler. This is an example of efficient structure.

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?

The tool is simple with no parameters, and the annotations provide the safety profile. An output schema exists to document return values, so the description does not need to explain them. The description adequately covers the tool's purpose for an agent, making the definition complete for this straightforward operation.

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 an empty input schema, so there is no parameter information to convey. The description correctly implies that no arguments are required. A baseline score of 4 is appropriate for empty parameter lists, as the description adds no unnecessary parameter details.

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 uses a specific verb ('List') and resource ('databases'), clearly stating the tool's function as listing all databases for a MongoDB connection. This distinguishes it from sibling tools such as 'list-collections' by specifying the scope of databases rather than collections.

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 clearly indicates the context of use: listing databases for a MongoDB connection. However, it does not explicitly mention alternatives or exclusions, such as noting that 'list-collections' should be used for collections instead. This is a minor gap, so it earns a 4 rather than a 5.

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