launch_on_virtual_display

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

Annotations indicate destructiveHint=true, and the description mentions creating a display if needed, which is a destructive (state-modifying) action. The description also provides a return format example, which adds transparency. However, it does not disclose potential side effects, such as what happens if the display creation fails or if the command is already running. The description adds some context beyond annotations but could be more thorough.

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 short and to the point, with a clear one-line purpose and structured Args/Returns sections. There is no unnecessary information. However, the Args line is a bit vague and could be slightly expanded without losing conciseness.

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?

Given the complexity of launching a GUI app on a virtual display (including potential prerequisites like Xvfb installation, error handling, and interaction with other virtual display tools), the description is too minimal. It does not explain prerequisites, failure modes, or how it relates to sibling tools like 'create_virtual_display' or 'stop_virtual_display'. The return format example is helpful, but overall completeness is lacking for a tool with many siblings.

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 description's Args line says 'display number and command line', which is a brief restatement of the schema's property descriptions. The schema already includes descriptions for 'command' and 'display', so the description adds minimal additional meaning. Context signals show 0% schema description coverage, but the actual schema has descriptions, making this a borderline case. The description does not provide formatting or constraints beyond what the schema offers.

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 'Launch a GUI app on an Xvfb virtual display (creates it if needed)', which is a specific verb-resource combination. It distinguishes from sibling tools like 'create_virtual_display' (which only creates the display) and 'launch_on_headless_desktop' (which launches on a headless desktop, not virtual display).

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 implies that this tool can create a virtual display if needed, so it can be used instead of creating a display separately. However, it does not explicitly state when to use this tool versus alternatives like 'launch_on_headless_desktop' or 'run_command', nor does it mention any prerequisites or conditions. With 51 sibling tools, more explicit guidance would be beneficial.

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