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

With no annotations, the description carries the burden of behavioral disclosure. It usefully states that no automation session is required and explains the return behavior, but it does not explicitly confirm that the operation is read-only/non-destructive or describe any prerequisites beyond a UDID. This is adequate but has room to be more explicit.

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 sentences with no filler. The first sentence defines the resource, and the second explains output modes and the no-session prerequisite. Every sentence earns its place and the most important information 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 relatively simple snapshot tool, the description covers platform, purpose, output shape, and key prerequisite. It lacks an explicit output schema or detailed return-format description, but the combination of the schema and description gives an agent enough to call 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?

Schema description coverage is 100%, so the schema already documents all three parameters. The description adds a small clarification that bundleId switches to a single-app snapshot, but it does not meaningfully extend the parameter guidance beyond the schema.

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 ('Snapshot') with a clear resource ('per-process CPU % and memory for a physical iOS device'). It also states the two output modes: top processes by CPU, or a single app when bundleId is provided, which distinguishes it from related tools like android_performance_snapshot and ios_ps.

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: it is for physical iOS devices, requires no automation session, and can focus on one app. It does not explicitly name alternatives or exclusions, but the platform and snapshot-vs-recording distinction is clear enough for an agent to choose this tool appropriately.

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