adb_input_pinch

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

With no annotations provided, the description carries full burden. It discloses the default method (parallel swipe injection) and the alternative (raw sendevent with root), providing transparency about behavior. It does not cover potential failure cases or side effects, but the method details are sufficient.

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 sentences, efficiently front-loading the purpose and then explaining methods. Every sentence adds value with no redundancy, making it easy to parse quickly.

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?

Given the tool's complexity (9 parameters, 4 required) and no output schema, the description covers the gesture type, injection methods, and method selection logic. It lacks details on return values or error handling but is sufficient for correct invocation.

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?

All parameters have descriptions in the schema (100% coverage), so the description adds limited per-parameter value beyond explaining the gesture mechanics and method selection. The schema already documents radius meaning and default values adequately.

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 multi-touch pinch or spread gesture with two fingers moving symmetrically. It uses specific verbs (perform, pinch, spread) and identifies the resource as a gesture on a device, distinguishing it from other input tools like tap or drag.

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 explains when to use this tool (for pinch/spread gestures) and describes the available methods (swipe, sendevent, auto) with their requirements (no root vs root). However, it does not explicitly mention when not to use it or compare with sibling tools like adb_input_drag, though the context is clear.

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