get_disk_usage

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

Annotations already establish readOnly, idempotent, openWorld, and non-destructive behavior. The description supplements this by clarifying the output pertains to each mounted partition's free and used space, which adds useful behavioral context beyond the annotations.

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 concise sentences: the first states the core capability and output, the second gives usage conditions, and the third provides a clear negative boundary and alternative. Every sentence earns its place without redundancy.

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 parameterless read-only tool, the description covers what the tool does, when to use it, and what to use instead for adjacent cases. It does not specify units or exact output formatting, but that is a minor gap given the explicit per-partition scope.

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 has zero parameters, so there is no parameter detail for the description to add. The baseline of 4 applies, and the description's scope clarification ('each mounted partition') is sufficient contextual information.

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 the tool reports disk space usage—specifically free and used space per mounted partition. It distinguishes itself from get_system_disk by explicitly excluding partition layout and filesystem type, making its 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?

It provides explicit when-to-use guidance ('when the user asks how much space is left or available') and an explicit exclusion ('Do NOT use for partition layout or filesystem type') with the named alternative get_system_disk. This leaves no ambiguity about tool selection.

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