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

Beyond the readOnlyHint and idempotentHint annotations, the description adds meaningful context by specifying that only the caller's files are listed and that results are sorted newest-first. This clarifies scope and ordering, which are not disclosed by the annotations. It does not mention pagination or return format, but for a simple read-only list, this is sufficient.

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 action and resource. Every word earns its place; there is no redundancy or filler.

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 tool with no parameters and no output schema, the description provides a clear scope and ordering, which is largely complete. It could optionally disclose what fields are included in the returned file list, but for a simple browsing tool, this is a minor omission and the description is adequate.

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 is empty (0 parameters), so the baseline score is 4. The description adds no parameter-specific details because there are none to describe, but it does specify the scope ('caller's stored files') and order ('newest first'), which adds meaning beyond the trivial empty schema.

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 a specific action ('List') on a specific resource ('the caller's stored files') with an ordering constraint ('newest first'). This distinguishes it from sibling tools like files_get, files_put, and files_delete, making the purpose unambiguous.

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 its usage: to browse the caller's files. However, it does not explicitly state when to use it over alternatives or when not to use it. Since there is no files_search sibling and it is the only list tool, the use case is fairly obvious, but explicit alternatives are absent.

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