Capture a VM console screenshot as a PNG and return the file path, or base64-encoded image on request.
Save a PNG of the VM console and return its path (base64 on request).
| Name | Required | Description | Default |
|---|---|---|---|
| vm | Yes | VM name as registered in vms.yaml | |
| base64 | No | Also return the PNG as base64 |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must disclose behavioral traits. It states that the tool saves a PNG and returns a path, optionally returning base64. This adequately describes the primary behavior. However, it does not mention side effects (e.g., whether it changes VM state) or any prerequisites (like VM must be running). Given the simplicity of the operation and the clear output, this is sufficient but not rich. A cautious agent might want to know if this is read-only, but the description implies a non-destructive capture.
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 a single, concise sentence that states the action, the output type, and the optional mode (base64). It is front-loaded with the main action, and every word earns its place. No fluff or redundancy.
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 simple tool with 2 parameters (1 required, 1 optional) and no output schema, the description is fairly complete. It specifies the output format (PNG path, optionally base64) and the parameter semantics. It could have benefited from mentioning whether the VM needs to be running or if it captures the current console state, but these are minor gaps given the tool's simplicity. The agent has enough to call it correctly.
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 100%, so the schema already documents both 'vm' (VM name) and 'base64' (return as base64). The description's mention of 'base64 on request' adds meaning to the 'base64' parameter, confirming its purpose)Skip. The 'vm' parameter is standard. Since the schema does the heavy lifting, this is a solid baseline 3.
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 uses a specific verb 'Save' with a clear resource ('a PNG of the VM console'), and states the output ('return its path (base64 on request)'). It clearly distinguishes itself from siblings like 'snap_take' or 'vm_state' by focusing on the console screenshot. This is unambiguous and actionable.
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 does not explicitly state when to use this tool versus alternatives, but the purpose is obvious enough that an agent can infer it is for capturing a console image. No exclusions or alternative tools are mentioned, but given the tool's specificity, this is adequate. However, it could have noted that this is not a VM snapshot but a console capture, which would help differentiate from 'snap_take'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.