icloud_storage

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

With no annotations, the description carries the disclosure burden and does meaningful work: it states sizes are in GiB matching Settings, that a warning is emitted when nearly full, and that the plan name is inferred rather than reported by Apple. This is exactly the kind of caveat that prevents an agent from misreading the plan name as authoritative. It never explicitly says the operation is read-only, which keeps it short of a 5.

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 tight sentences, front-loaded with the resource and its returned fields, followed by the two caveats an agent actually needs (units and inferred plan name). No filler, no restating of the tool name.

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?

There is no output schema, so the description must describe the return payload, and it does comprehensively: size, used, free, percent, warning, and category breakdown. The only gap is failure conditions such as not being signed into iCloud or storage data being unavailable, which are not addressed.

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 there is nothing for the description to disambiguate; the baseline for 0 params applies. The description correctly spends no space on inputs and instead documents the shape of the result.

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 resource (iCloud storage and plan) and enumerates exactly what the summary contains: plan size, used/free space, percent used, near-full warning, and per-category usage. No sibling tool overlaps with storage reporting, so the agent can select it unambiguously.

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?

Usage is implied by the resource rather than stated: an agent can infer you call it for a storage overview, but there is no explicit when-to-use, when-not-to-use, or alternative (e.g. per-category detail tools). A single clause like 'use when the user asks about iCloud space' would lift this to a 4.

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