click_screen

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

With no annotations, the description carries the full behavioral burden and does well: it discloses that the tool fires onPress of the nearest pressable, focuses TextInputs, and returns a new screenshot. It leaves out failure behavior and does not mention long-press support in prose.

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 tightly written sentences with no wasted words. It front-loads the primary action and then adds the target-element and alert cases efficiently.

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 four-parameter UI automation tool with no output schema, the description is largely complete: it explains targeting, tap side effects, and the returned screenshot. The main gap is the unmentioned long-press behavior and no guidance on failure cases.

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 low at 25%, so the description must compensate. It adds meaning for x, y (screen dp coordinates), target (testID, accessibilityLabel, visible text), and alert target syntax, but does not explain the "long" parameter beyond the schema's terse note.

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 states a specific verb and resource: "Taps the screen" at coordinates or by target element. It clearly separates the two targeting modes and is distinguishable from siblings like type_text and scroll_screen, though it does not explicitly name alternatives.

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?

It explains when to use coordinates versus a target (testID, accessibilityLabel, or visible text) and gives a special alert syntax. It does not explicitly compare against siblings such as press_key or use_target, but the usage context is clear.

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