System Df Tool

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

readOnlyHint=true already establishes the safety profile, and the output schema documents the return structure. The description adds modest value by naming the three aggregation dimensions (images, containers, volumes), implying a summary rollup rather than a detailed listing, but says nothing about scope (local vs all storage), totals/reclaimable space, or performance.

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?

Two short sentences, action first, return shape second. No filler and nothing that could be cut without losing information.

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, this is nearly complete — the agent knows it is safe, takes no arguments, and returns usage broken out by images, containers, and volumes. Only the distinction from system_info_tool is left unresolved.

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 the baseline is 4; there are no parameter semantics to explain and the description introduces nothing misleading about inputs.

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: 'Get Podman disk usage', which maps cleanly to the `podman system df` concept and is distinct from per-object siblings like image_list_tool or volume_list_tool. It does not explicitly differentiate itself from system_info_tool, the closest ambiguous sibling.

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 call this versus system_info_tool (general host/engine info) or the individual list tools. The agent must infer that this returns aggregate disk consumption rather than per-object detail.

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