disk_usage

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

With no annotations, the description carries the full behavioral burden. It does disclose one non-obvious trait beyond the schema: the path must be an 'exactly allowlisted' mount path, so arbitrary paths are rejected. However it never says where the allowlist comes from, how to discover valid entries, whether the tool is read-only, or what happens on a rejected path.

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?

A single tight sentence with the resource stated first and the constraint second; nothing is wasted. It is perhaps too terse given the undefined allowlist, but that is a completeness issue rather than verbosity.

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?

An output schema exists, so return values need no explanation, and the tool has only one parameter. The remaining gap is the 'exactly allowlisted' constraint: an agent cannot tell how to choose a valid path, and the schema default of '/' may not be allowlisted. That ambiguity keeps it at minimum-viable completeness.

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 coverage is 0% for the single 'path' parameter, so the description must compensate. It clarifies that the value is a mount path (not an arbitrary filesystem path) and that it must be exactly allowlisted, which adds real meaning over the bare schema. It still gives no format examples or a way to enumerate valid values.

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 ('Report disk usage') plus a scope qualifier ('exactly allowlisted mount path'). That is far more precise than a tautology, and the sibling list (memory, service_status, uptime, etc.) covers different resources, so disambiguation is implicit. It stops short of an explicit contrast with a sibling, which is the only gap.

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 implies the tool is for checking disk usage on a mount, and 'exactly allowlisted' functions as a usage constraint rather than a when-to-use rule. There is no statement of when this is preferable to a sibling tool or any alternative to use instead when the path is not allowlisted.

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