Frontmost app

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

The readOnlyHint and idempotent annotations already establish safety, and the description adds only that the result is a name. It does not contradict annotations, but also does not disclose edge-case behavior or system-specific limitations.

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?

One clear, front-loaded sentence communicates the tool's purpose without filler or unnecessary detail.

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 read-only, no-parameter tool, this is nearly complete. It could optionally mention behavior when there is no frontmost application, but the description covers the core invocation context well.

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?

There are no parameters, so parameter documentation is not needed. The description appropriately focuses on what the tool returns rather than input semantics.

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 and object: "Return the name of the frontmost (active) application." This distinguishes it from sibling tools like list_apps, list_processes, and system_info.

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?

Usage context is implied by the tool's name and description, but there is no explicit guidance about when to choose this over sibling tools or what to do when no frontmost application exists.

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