vm_screenshot

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

No annotations are provided, so the description carries the burden. It discloses the output medium (PNG file path) and the intended downstream action (read with vision), but says nothing about preconditions — e.g. whether the VM must be powered on or a display attached — or what happens on failure.

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?

Three short sentences, front-loaded with the action, then the when, then the purpose. No filler; every sentence carries information.

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?

An output schema exists, so return values needn't be spelled out, and the usage guidance is strong for a one-parameter tool. The remaining gap is the unexplained 'name' parameter.

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 is a single parameter 'name' with 0% schema description coverage, so the description must compensate and does not. It never mentions what 'name' identifies or how it relates to a VM instance.

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 and resource: 'Capture the VM display to a PNG and return its path.' No sibling (vm_status, vm_log, vm_exec, etc.) captures the display, so the agent can distinguish it immediately.

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 explicit timing triggers — 'after boot, after each setup screen, and after app tests' — which is far more than most definitions offer. It doesn't name alternatives or a when-not condition, but for a capture primitive the positive triggers are clear guidance.

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