create_virtual_display

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

Annotations already indicate idempotentHint=true and destructiveHint=false. The description adds value by explaining the tool starts a real X server and returns a structured JSON with display info, PID, etc. It also mentions automation and screenshotting capabilities beyond annotations.

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 concise and well-structured: a one-sentence purpose, a paragraph on usage context, and a clear parameter/return section. It front-loads the core action and is free of unnecessary content.

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 tool's moderate complexity, the description together with annotations and schema provides sufficient information for an AI agent. It covers purpose, usage context, parameters, and return value. Minor omission: does not mention prerequisite (Xvfb must be installed) or platform (Linux), but these are implied by the tool's nature.

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 only lists parameter names and types ('display number, width, height, depth'), adding no meaning beyond what the input schema's property descriptions already provide. Since the schema descriptions are detailed (coverage 100% per schema, though context says 0%—likely referring to the description text not covering parameters), the description adds minimal value.

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 the tool starts an Xvfb virtual display for headless GUI operation. It distinguishes from siblings by noting it's the Linux counterpart of Windows headless desktop and is used for automation and screenshotting, though could more explicitly contrast with the sibling 'create_headless_desktop'.

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 provides clear context: use when you need to run GUI apps headlessly for automation or screenshots. It explains the benefit (no visible desktop occupation) but does not explicitly state when not to use or list alternative tools.

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