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

With no annotations provided, the description carries the full burden of disclosing behavioral traits. It adds valuable context about the return message on failure ('Returns "no HID available" on iOS 17.x / no-tunnel'), the single-contact restriction, and coordinate system (iOS screen points). It does not mention other traits like whether the operation blocks or what happens on successful completion, but for a simple gesture tool it is sufficiently transparent.

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 extremely concise: three sentences that front-load the core purpose, then clarify coordinate semantics and the key limitation. Every sentence adds value, with no redundancy or filler.

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 simple gesture tool with fully described schema parameters, the description sufficiently covers the core behavior, coordinate system, and failure mode. It is complete enough for an agent to invoke it correctly and anticipate the 'no HID available' error on unsupported iOS versions.

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 100%, so the baseline is 3. The description does not add much beyond the schema; it merely reiterates that coordinates are iOS screen points (already in schema) and mentions single-contact (not parameter-related). It does not explain the norm flag or durationMs beyond what the schema provides.

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 states the tool performs a long-press (hold) at (x,y) via the direct input path, with a specific verb and resource. It also distinguishes itself from siblings like ios_long_press by noting 'no automation session needed', making its unique purpose clear.

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 for when to use this tool: 'via the direct input path (no automation session needed)' contrasts it with session-based alternatives. It also mentions the single-contact limitation and the iOS 17.x / no-tunnel error condition, but does not explicitly name alternative tools or provide when-not-to-use scenarios beyond that limitation.

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