file_list

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

Annotations already declare readOnlyHint=true, so the read-only nature is fully covered. The description adds minimal behavioral context beyond the annotation. It doesn't mention whether hidden files are shown, sorting behavior, or output format details, but with the readOnlyHint annotation covering the main safety profile, a baseline 3 is appropriate.

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 with no wasted words. It's appropriately front-loaded with the primary action. Could be slightly more informative but achieves efficiency as-is.

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?

Given the simplicity of the tool (list directory, 2 params, fully covered schema, readOnlyHint annotation, and an output schema provided), the description is essentially adequate. The output schema exists so return values don't need describing. Some mention of absolute-path requirements or error conditions (e.g., non-existent path) could improve completeness, but the tool's low complexity keeps requirements modest.

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% as both parameters (path, serial) have descriptions. The path parameter is described with an example value (/sdcard/), which adds useful context. The description itself doesn't add meaning beyond what the schema provides, so baseline 3 is appropriate.

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 states the verb (list) and resource (directory contents) clearly. It distinguishes from file_push/file_pull siblings since it's a read-only listing operation. However, it's somewhat short and doesn't explicitly contrast with sibling tools like device_list or app_list, so sibling differentiation is partial.

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 when-to-use or when-not-to-use guidance is provided. It doesn't mention alternatives like shell_exec for more advanced file operations, file_push/file_pull for file transfers, or app_list for application files. The description provides no context for choosing this tool over related ones.

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