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

The readOnlyHint and destructiveHint annotations already establish the safety profile, so the description only needs to add context. It contributes the fact that the folder is the caller's own root (implying authentication scoping) but says nothing about error behavior when no root exists or what 'metadata' comprises beyond what the output schema covers.

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?

A single front-loaded sentence with no filler or redundancy. It is efficiently sized, though the minimal length leaves room to add routing guidance without becoming bloated.

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 zero-parameter, read-only tool with an output schema that documents the returned metadata, the description covers what is needed to invoke it correctly. The only real gap is sibling differentiation against filesfm_get_folder_info, which a slightly longer description could close.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; the empty schema with additionalProperties=false is unambiguous on its own. Baseline 4 applies for a parameterless tool.

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?

States a specific verb and resource ('Return ... root folder metadata') with a clear scope qualifier ('authenticated user'). It does not, however, distinguish itself from the closely related siblings filesfm_get_folder_info and filesfm_list_folder, so an agent must infer that 'root' means no folder ID is required.

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: an agent can infer this is the entry point when no folder ID is known, but the description never says so, nor does it mention when to prefer filesfm_get_folder_info for a known folder or filesfm_list_folder for contents. No exclusions or prerequisites are given.

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