get_current_ui_labels

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

With no annotations, the description must carry the full burden of behavioral disclosure. It reveals the return type and node properties, but does not state whether the operation is read-only, what happens if no UI is present, or if any device state is required. This is partial transparency but not comprehensive.

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 two concise sentences with no waste. The core purpose is front-loaded, and the additional property detail is brief and relevant. It earns its place without redundancy.

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 getter with no parameters and no output schema, the description explains the return content adequately. However, it does not disambiguate from the sibling get_current_focused_nodes, nor does it mention edge cases like empty results or device screen state, leaving some context gaps for an agent.

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?

The tool has zero parameters and an empty schema. The description explicitly states 'No parameters are required,' which is a helpful confirmation beyond the schema and aligns with the baseline 4 for zero-parameter tools, adding clear value.

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 a specific verb (returns) and resource (UI nodes on device screen), specifies scope (visible, text labels and content descriptions), and differentiates from the sibling get_current_focused_nodes by emphasizing 'currently visible' and 'focusing on text labels and content descriptions.'

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 no guidance on when to use this tool versus alternatives like get_current_focused_nodes. It does not mention exclusions, conditions, or prerequisites, leaving the agent to infer usage context.

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