foreground_app

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

With no annotations, the description carries the burden of behavioral disclosure. It implies a read-only observation of the current screen state and explains the output's role, but it does not explicitly state that it has no side effects or how it behaves when no app is in the foreground.

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 short, purposeful sentences. The result is stated first in an efficient noun phrase, followed by one sentence explaining the usage context. No excess or 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, zero-required-parameter read tool, the description gives enough context to invoke without arguments and understand the returned concept. However, the complete absence of serial parameter documentation and any behavioral caveats leaves moderate gaps.

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 input schema has one optional 'serial' parameter with 0% description coverage, and the description does not mention it at all. The agent gets no guidance on what serial selects or what the default null behavior means.

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 defines the tool's output: the name of the currently visible foreground application and activity. It also distinguishes this from visual or structural tools by framing it as the lightweight context before requesting ui_dump or screenshot.

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 explicit situational guidance: use this to obtain screen context before calling ui_dump or screenshot. It does not mention alternative tools for similar foreground/process queries, but the intended workflow is clear.

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