storage_summary

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

With no annotations, the description carries the full burden of behavioral disclosure. It reveals a key trait: skipping tmpfs/overlay/virtual mounts, and implies a read-only operation via `df`. It could add details about permissions or error behavior, but the disclosed filtering behavior is significant and goes beyond the tool name.

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 dense sentences cover purpose, return content, and exclusions with no wasted words. The most important information ('per-mount usage') is front-loaded.

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, no-output-schema system tool, the description is complete. It explains what the tool does, what data it returns, and which mounts it skips. No additional context is necessary for an agent to select and invoke it correctly.

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 and an empty schema. The baseline for a no-parameter tool is 4, and the description adds no parameter information because none is needed.

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 uses a specific verb and resource ('per-mount usage for the OS + data disks') and enumerates exact fields (device, mount, fstype, total/used/avail bytes, percent). It distinguishes itself from sibling tools by explicitly stating it skips tmpfs/overlay/virtual mounts.

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?

The description provides clear context for when to use this tool (OS and data disks) and explicitly notes exclusions (virtual mounts), which implies when not to use it. However, it doesn't name alternative tools or give a direct 'use this instead of...' recommendation, so it doesn't fully reach a 5.

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