launch_on_headless_desktop

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

Annotations already mark this as destructive and not read-only. The description adds valuable context: the process runs with a full GUI on a hidden desktop, the desktop is created if needed, and the visible desktop is unaffected. This discloses side-effects (process launch, desktop creation) beyond the annotations. No contradiction found.

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 compact and well-structured: a clear purpose sentence, a usage note, then Args/Returns sections. Every line conveys necessary information without fluff. The front-loaded purpose statement makes it easy to understand the tool at a glance.

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 tool that launches GUI apps on a hidden desktop, the description is remarkably complete. It explains the hidden-desktop behavior, how to interact with the launched app (list_headless_windows, screenshot), the return payload (JSON with ok, desktop, pid, command), and that the visible desktop is untouched. The output schema is described textually, and no critical operational details are missing.

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 0%, meaning this description must compensate for parameter documentation. It only says 'desktop name and command line,' which adds no detail beyond the schema's own descriptions. It fails to mention the default name, required command, or how the command should be formatted. The schema already covers these, but the description adds no extra value for an agent trying to understand parameter 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 opens with a specific verb+resource+environment: 'Launch a GUI application on an off-screen desktop (creates it if needed).' This clearly states the core function and distinguishes it from siblings like create_headless_desktop and launch_on_virtual_display. The phrase 'creates it if needed' also clarifies that it combines desktop creation with app launch.

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 workflow guidance: use list_headless_windows to find windows, drive with background input, and capture with screenshot(hwnd=...). It also states the visible desktop is never touched, implying when to choose this tool over alternatives. However, it does not explicitly name when-not-to-use or compare with launch_on_virtual_display, so it falls just short of a 5.

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