Capture the entire screen and save it as a PNG file, returning the file path to support visual UI automation workflows.
全屏截图并保存为 PNG 文件，返回文件路径。
| Name | Required | Description | Default |
|---|---|---|---|
| path | No | 保存路径（可选，默认临时目录） |
Changes observed during successful MCP inspections.
v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must carry the full behavioral disclosure. It does state the primary behavior, file format, and return value. However, it does not disclose side effects such as overwriting existing files, whether the path is expected to be absolute or relative, or any permission/system requirements.
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, compact sentence that front-loads the action, format, and return value. There is no filler or repetition of schema details.
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 one optional parameter and no output schema, the description adequately covers the key facts: what is captured, the saved format, and the returned value. It could add edge-case behavior such as error handling or path creation, but the core contract is complete.
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%, with the path parameter already documented as optional and defaulting to a temporary directory. The tool description adds the overall PNG-saving context but does not add parameter-specific meaning beyond what the schema already provides, so baseline 3 is appropriate.
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 states a specific verb, resource, and outcome: take a full-screen screenshot, save it as a PNG, and return the file path. This also distinguishes it clearly from the sibling tools (desktop_click, desktop_locate, desktop_click_target), which perform different actions entirely.
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 makes the use case clear: capturing the full screen to a PNG file. It does not explicitly mention when not to use it or name an alternative, but the sibling tools are action-type tools, so there is little ambiguity about when this screenshot tool is appropriate.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.