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

Annotations already declare readOnly=false, destructive=true, and openWorld=true, so the safety profile is covered. The description adds real operational context beyond them: start returns a live view URL, input is by pixel coordinates, keys use xdotool names, and open/launch spawn external programs.

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?

Front-loads the purpose, then a compact semicolon-delimited enumeration of capabilities. Dense but well organized for a 16-action tool, with the screenshot note last as a natural follow-up.

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?

With no output schema, the description carries value by noting that start yields a live view URL and that screenshot reveals results. It does omit several enum actions (stop, cursor, status, mouseDown/mouseUp), leaving minor gaps for a multi-action tool.

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 coverage is 61%, and the description compensates by mapping parameters to actions ('start (width,height)', mouse via pixel coordinates, keys, url, argv/launch). This action-to-parameter mapping is not present in the schema itself, so it adds genuine value despite coverage gaps on x/y/width/height/button.

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?

States a specific verb+resource ('Drive a sandbox's Linux desktop') and enumerates the concrete operations it supports, so an agent immediately knows this is the interactive input tool. It explicitly distinguishes itself from the sibling runtime_sandboxes_desktop_screenshot, which it delegates result inspection to.

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?

Gives clear context ('like a person') and names the complementary tool to use for results ('Take runtime_sandboxes_desktop_screenshot'). It does not, however, state when to prefer this over runtime_sandboxes_browser or runtime_sandboxes_exec, which are plausible alternatives.

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