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

The annotation readOnlyHint=true already establishes the tool's safety profile. The description adds no additional behavioral traits beyond the basic listing action, such as non-recursiveness or default path behavior. Since the annotation covers the key safety aspect, a score of 3 is appropriate—no contradiction, but no extra context.

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 sentence with no filler. Every word contributes to conveying the tool's purpose, making it extremely concise and efficiently structured.

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 an output schema present and well-documented parameters. The description fully captures the tool's essence for an AI agent, and no additional return-value details are needed due to the output schema. It is complete for its intended scope.

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 input schema fully describes both parameters (all and path) with their types, defaults, and descriptions, providing 100% coverage. The tool description adds no parameter-level information. Thus, the baseline of 3 applies; the schema does the heavy lifting.

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 'List the contents of a directory' uses a specific verb and resource, clearly distinguishing it from sibling tools like read (file content), find (search), and write/edit (modify). It is unambiguous and immediately conveys the tool's function.

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 is too brief to provide explicit usage guidance or mention alternatives. While the purpose implies listing directory contents, it does not state when to prefer this over find or grep in recursive or search scenarios. Usage context is only implied by the tool's name and purpose.

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