Current app

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

With no annotations, the description carries the full burden and only discloses the identity of the returned value. It says nothing about whether accessibility/automation permissions are required, what happens when no app is foregrounded, or whether the result is a string or a structured object.

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?

A single short sentence with no filler. It is appropriately sized, though it leads with a noun phrase rather than an action, which slightly weakens front-loading for a first-time reader.

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-param read tool this is close, but with no output schema and no annotations, the description should specify the return shape and failure behavior. It only partially does so by noting the bundle ID / process form.

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 takes zero parameters, so the baseline is 4; there is nothing for the description to compensate for. Schema coverage is 100% on an empty object.

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 names a specific resource — the foreground app, identified by bundle ID / process — which is distinct from list_apps (all apps) and device_info. It lacks an explicit verb, but the noun phrase is unambiguous about what is returned.

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?

There is no when-to-use guidance and no mention of alternatives such as list_apps or device_info. The phrase 'currently in the foreground' hints at the context, but the agent must infer when this tool is preferred over its siblings.

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