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

Annotations already provide readOnlyHint=true and destructiveHint=false; the description adds valuable context beyond that: it refuses credential and identity locations and states it is Spotlight-free. This goes beyond what annotations alone declare.

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, front-loaded with the core action, and no filler. Each sentence earns its place: core function, scope, and security exclusions all appear in compact form.

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 output schema plus annotations carry return values and safety, and the description covers base function, scope, and sensitive-path behavior. It is complete for a simple list tool; finer details like hidden files or error behaviors are not critical for correct invocation.

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?

Schema coverage is 100% and both parameters (path and limit) already have descriptions. The tool description does not add parameter-level meaning beyond the schema, so it meets the baseline for high schema coverage.

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 ('Lists') and resource ('files and folders in a directory') and sharpens scope with 'any folder on this Mac' and 'Spotlight-free'. It clearly differentiates from search-like siblings, but it does not explicitly distinguish itself from the adjacent file_list sibling.

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?

No explicit guidance on when to prefer this tool over alternatives such as file_list or finder_search. The sensitive-path refusal gives clear negative boundaries, and 'Spotlight-free' implies a non-indexed file list, but the description leaves the when/when-not comparison mostly implicit.

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