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

With no annotations, the description carries the full burden. It discloses atomic release behavior (one frame), the meaning of coordinates (where each finger ends), and an important failure mode (returns 'no HID available' on iOS 17.x / no-tunnel). This gives the agent a realistic picture of runtime behavior and edge cases.

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 three terse sentences, all information-dense. The purpose and key behavioral caveat are front-loaded, with the error condition appended as a discrete fact. No filler or redundant restatement 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?

For a tool with 3 params, 100% schema coverage, and no output schema, the description covers everything needed to invoke it correctly: what it does, what the inputs mean, the critical timing rule, and the known error scenario. The pairing with ios_contacts_hid and ordering constraint are explicitly 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?

Schema coverage is 100%, and the points parameter schema already states 'Where each finger is when it lifts, in the same order as ios_contacts_hid'. The description repeats that same information ('Coordinates are where each finger ends') without adding new detail about udid or norm. Baseline 3 is appropriate because the schema already documents the semantics.

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 first sentence is a specific verb-resource pair: 'Lift held contacts placed by ios_contacts_hid.' It distinctly identifies this as the release counterpart to ios_contacts_hid Henshaw, separating it from generic ios_release_hid and the broader HID family.

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 gives clear context for when to use the tool: after ios_contacts_hid, to lift all held fingers. It explains a critical usage constraint ('Every finger lifts in ONE frame') and why ('the device reads as the gesture continuing'). However, it doesn't explicitly name alternatives like ios_release_hid or state when not to use this tool, so it stops short of full when/when-not guidance.

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