system_df

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

The '[READ]' prefix indicates read-only behavior, which is good. However, with no annotations, the description should disclose more traits (e.g., auth, performance impact). No additional behavioral details are provided.

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?

Extremely concise: two sentences plus an arg list. Front-loaded with the '[READ]' tag. Every word adds value, no 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 simple disk-usage tool with one optional parameter, the description covers the main purpose and parameter usage. Lacks details about output format or units, but overall sufficient given the tool's simplicity.

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 has 0% coverage, so description must compensate. It explains the 'target' parameter as coming from config and defaults to null, adding meaning beyond the schema's title and type. However, no formatting or constraints specified.

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 it provides a disk-usage breakdown for images, containers, volumes, and build cache, with a read-only indicator. It distinguishes from siblings like image_disk_usage by listing multiple categories, but does not explicitly differentiate itself.

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 guidance on when to use this tool versus alternatives such as image_disk_usage or prune tools. The description only states what it does, not context for selection.

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