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

Annotations already establish readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the home-directory default, the returned attributes, and the sort order (directories first, then alphabetical), which tells the agent what output shape to expect.

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 tight sentences with zero filler; the core action and default scope come first, then return fields, then ordering. Nothing is repeated or padded.

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?

For a two-parameter, read-only listing tool with a full output schema and clear annotations, everything an agent needs to call it correctly is present: default path, hidden-file behavior, and result ordering. The return-value sentence is slightly redundant against the output schema but harmless.

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 description coverage is 100%, so both parameters are already documented in the schema. The description restates the same defaults (home directory, hidden files excluded implied by show_hidden) without adding syntax, path-validation behavior, or examples, so the baseline 3 applies.

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?

Opens with a specific verb+resource ('Lists files and folders in a local directory') and pins the scope with a default location. That clearly separates it from file_read or file_search, but it never distinguishes itself from the very similar sibling finder_list, leaving an agent to guess which local lister to pick.

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?

Usage is only implied by the tool's shape – enumerate a directory when you need its contents. There is no explicit when-to-use guidance, no exclusions, and no pointer to alternatives such as finder_list for Finder-specific listings or file_search for lookups by name.

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