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

Annotations already declare this is a write (readOnlyHint=false), idempotent, non-destructive, and not open-world. Beyond that, the description discloses the two operational modes and the session precondition, which is genuinely useful context not present in structured fields. It does not describe failure behavior when no session exists, keeping it out of the top band.

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, zero filler, and the primary action is front-loaded before the mode-specific caveat. Every clause carries information an agent needs to decide how to invoke it.

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 and the annotations cover the safety profile, so the description only needs to carry preconditions and modes, which it does. It could be slightly more complete by noting what happens on failure (e.g., no active session), but nothing essential to a correct call is missing.

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% with only two simple parameters (udid, content), so the schema fully documents them and the 3 baseline applies. The description adds no formatting or size constraints on 'content' beyond what the schema already states.

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 ('Set the clipboard (pasteboard) content on an iOS device') and explicitly names the sibling it behaves like in one mode (ios_clipboard_set_hid). An agent can distinguish this tool from ios_get_pasteboard and the generic device_clipboard_set without opening any schema.

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?

Gives a clear conditional context: on direct-input-only devices it writes over the direct input path with no session, otherwise an active iOS automation session is required. It stops short of saying when to prefer this over ios_clipboard_set_hid or device_clipboard_set, so it is context-rich but has no explicit routing advice.

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