Capture a browser-rendered page and save it as an image file, returning the path for visual verification or troubleshooting. Optionally wait for a selector and capture the full page.
对页面截图（浏览器渲染）并保存为图片文件，返回文件路径。用于人工核对渲染结果/排障；图片本身不内联返回。
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | 目标网址（http/https） | |
| path | No | 保存路径（可选；默认 outputs/mcp_shots/<时间戳>.png） | |
| full_page | No | 整页截图（默认 false=视口） | |
| wait_selector | No | 等该元素出现后再截图（可选） |
Changes observed during successful MCP inspections.
v2.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It helpfully discloses that the page is browser-rendered, the image is saved to a file, the file path is returned, and the image is not returned inline, but it omits operational details such as overwrite behavior, permissions, timeouts, or other side effects of writing a file.
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 compact and front-loaded, first stating the action and output, then the intended use. Every clause adds useful information with no 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?
Given a fully described four-parameter schema and no output schema, the description covers the essential return behavior by stating that the file path is returned and the image is not inline. It is nearly complete for this tool, though it could say more about file handling or constraints.
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 explains url, path, full_page, and wait_selector in detail. The description adds no parameter-specific meaning beyond what the schema provides, so the baseline of 3 applies.
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 and resource: screenshot a page via browser rendering, save it as an image file, and return the file path. This is clear enough to distinguish it from scraping or crawling siblings by its image-file output, although it does not explicitly name or contrast those siblings.
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?
It gives a clear usage context: manual verification of rendering results and troubleshooting. It does not specify when not to use it or explicitly compare it with alternatives such as scrape or crawl, so it stops short of full routing guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.