fm_disk_usage

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

No annotations are provided, so the description must carry the full behavioral burden. It only says 'Disk usage for a path' and does not disclose whether the result is recursive, file-level or directory-level, how units are represented, or whether paths must be directories. This is a minimal read-style tool, but the description still leaves key behavior unspecified.

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 opening sentence is concise and front-loaded. However, the 'Args: path: Path' section is redundant with the input schema and adds no value, making the structure slightly wasteful for an already trivial description.

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 tool has only one optional parameter and an output schema, so the bar for completeness is lower. Even so, the description does not explain the purpose relative to the many sibling file-manager and system tools, nor does it clarify what kind of path is expected or what kind of 'disk usage' is reported. An agent could probably invoke it, but with limited confidence about the result.

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 0%, so the description must compensate for the underdocumented parameter. It only repeats 'path: Path', adding no meaning beyond the schema's own 'path' string property. There is no clarification about absolute/relative paths, file versus directory, or the meaning of the default '/'.

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 a clear operation ('disk usage') and a specific resource ('a path'), so an agent can understand the basic function. However, it does not differentiate this from related siblings like system_disk or fm_tree, so it stops short of a 5.

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?

There is no guidance on when to use this tool versus alternatives such as system_disk, fm_list, or fm_tree. No context, prerequisites, or exclusions are provided, leaving the agent to infer usage from the name alone.

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