Disco

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

Annotations already declare readOnlyHint=true, so the read-only safety profile is covered. The description adds useful scope information (internal plus mounted external disks) and the three data dimensions, but it does not disclose units, how missing/unmounted external disks are handled, or potential error conditions.

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 description is a single efficient sentence with no filler. The core resource and metrics are front-loaded, and every word adds relevant meaning.

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, low-complexity tool, the description is largely complete: it names the exact data returned and the disk scope. The only notable gap is the absence of units or return format, which would be helpful since there is no output schema, but it is not essential for invoking the tool 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, so the baseline is 4. There is no parameter semantics for the description to clarify, and the description instead helpfully enumerates what the tool reports (total, used, free), which is appropriate compensation.

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 identifies the resource (disk), the scope (internal and mounted external disks), and the exact metrics returned (total, used, free). Although it is a noun phrase rather than an explicit verb, the tool name 'get_disk' makes the action unambiguous, and the resource clearly distinguishes it from siblings like get_memory and get_cpu.

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 intended use is implied: use this tool when disk space information is needed. However, the description gives no explicit when-to-use guidance, no exclusions, and no mention of alternatives, even though there are no direct disk-related siblings to confuse it with.

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