适用于 Claude Code 的 Cursor 风格设计笔。在有头 Chromium 浏览器中对任意网页进行点击、框选或绘图，Claude 即可获得精确的源文件、行号、CSS 选择器和截图——随时准备进行编辑和验证。
三种可视化转源码模式：
模式 | 交互方式 | Claude 获取的内容 |
元素 (element) | 悬停 + 点击单个元素 |
|
区域 (area) | 拖拽框选 |
|
绘图 (draw) | 自由红笔绘制，按 Enter 键完成 |
|
所有截图均保存为 /tmp 目录下的 PNG 文件并返回路径——你的 MCP 客户端永远不会触及 base64 的上下文限制。
React 源码解析在 Next.js 开发模式下通过 _debugSource fiber 属性（由 @babel/plugin-transform-react-jsx-source 附加）工作。生产环境构建会移除此属性；请参阅下方的 生产环境源码映射。
Related MCP server: software-design-mermaid-mcp
You: "Make this button rounder"
Claude: [designer_open http://localhost:3000/dashboard]
Claude: [designer_pick mode=element]
You: *click the button*
Claude: → source: Button.tsx:42
Claude: [Edit Button.tsx add rounded-full]
Claude: [designer_screenshot selector=#cta-btn] ← after screenshot for verification先决条件：Node 18+，Claude Code，可用的 macOS/Linux 环境（Playwright Chromium）。
git clone https://github.com/YOUR_USER/designer-mcp.git
cd designer-mcp
npm install
npx playwright install chromium # one-time browser download将 MCP 注册到 Claude Code（用户范围 = 在每个会话中可用）：
claude mcp add --scope user designer-mcp node "$(pwd)/index.js"安装 Claude 技能，以便未来的会话了解该工作流：
mkdir -p ~/.claude/skills/designer
cp SKILL.md ~/.claude/skills/designer/SKILL.md重启 Claude Code。你应该能在会话中看到 designer_* 工具和一个 designer: 技能。
启动你的 Next.js 开发服务器（用于源码映射）：
cd your-nextjs-app && npm run dev然后在 Claude Code 中：
"在设计器中打开 http://localhost:3000/settings 并让我选择页眉。"
Claude 将调用 designer_open(...)，然后调用 designer_pick({ mode: "element" })。Chromium 窗口会弹出到前台，你的光标变成十字准线，点击页眉即可。Claude 将获得 source.fileName + lineNumber 并可以直接进行编辑。
单个元素 — 使用 element
同一区域内的多个相关元素 — 使用 area（拖拽一个框；返回中心点落在框内的所有元素）
可视化标注/解释 — 使用 draw（红笔，按 Enter 完成，按 Esc 取消）
_debugSource 仅限开发环境使用。若要在生产构建中使用拾取器，请在 next.config.js 中启用源码映射：
module.exports = {
productionBrowserSourceMaps: true,
// ...
};拾取器目前在生产环境中返回 source: null；未来版本将通过已部署的 sourcemap 解析选择器。欢迎提交 PR。
所有工具均通过 MCP 公开；Claude Code 将它们视为 mcp__designer-mcp__*。
designer_open(url: string)启动或重用有头 Chromium 实例并导航。通过 bringToFront() + AppleScript 提示在 macOS 上将窗口置于前台。
designer_pick({ mode?: "element" | "area" | "draw" })激活拾取器覆盖层。当用户完成交互（或按 Esc 取消，或 180 秒超时）时返回。
designer_screenshot({ selector?: string })获取页面或特定元素的 PNG。返回 { path, bytes }。
designer_close()关闭浏览器并释放 Playwright 资源。
启动一个由 Playwright 控制的有头 Chromium 实例。每个进程单例。
designer_pick 将一个小型的原生 JS 覆盖层 (picker.js) 注入页面。该覆盖层：
元素模式 — 追踪 mousemove/click，用蓝色勾勒悬停目标，解析一个相对唯一的 CSS 选择器，遍历 React fiber 链以获取 _debugSource，并返回给 MCP。
区域模式 — 橡皮筋式框选；鼠标抬起时，收集所有中心点落在框内的元素（按选择器去重）。
绘图模式 — 全视口画布覆盖层；将笔迹捕获为点数组；按 Enter 键完成。
服务器每 200 毫秒轮询一次 window.__designerResult，最长持续 180 秒。
完成后，将适当的截图（元素/区域裁剪/全视口）保存到 /tmp 并返回路径。
欢迎提交 PR，特别是在以下方面：
生产环境 sourcemap 解析
Kestrel/React Native 拾取器（目前仅支持 Web）
元素模式下的多元素累加（Cmd-点击以添加）
VS Code "在编辑器中显示" 集成
MIT
Close the designer browser and release resources.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It mentions 'release resources', which hints at cleanup behavior, but does not disclose critical details like whether this is destructive (e.g., closes without saving), requires specific permissions, or has side effects. For a tool with no annotations, this leaves significant behavioral gaps.
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, efficient sentence that directly states the tool's purpose with no wasted words. It is appropriately sized and front-loaded, making it easy to understand immediately without unnecessary elaboration.
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 the tool's simplicity (0 parameters, no output schema, no annotations), the description is adequate but incomplete. It covers the basic action but lacks details on behavioral aspects like what happens to unsaved work or error conditions. For a tool that likely interacts with a browser, more context would be helpful despite the low complexity.
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?
The tool has 0 parameters with 100% schema description coverage, so the schema fully documents the lack of inputs. The description does not add parameter details, which is unnecessary here. Baseline is 4 for 0 parameters, as no additional parameter semantics are needed beyond the schema.
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 clearly states the specific action ('Close') and resource ('the designer browser'), distinguishing it from sibling tools like designer_open (open), designer_pick (pick), and designer_screenshot (capture screenshot). It provides a complete verb+resource combination that is unambiguous.
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 implies usage when the designer browser is open and resources need releasing, but it does not explicitly state when to use this tool versus alternatives or any prerequisites. It lacks explicit guidance on when-not-to-use or named alternatives, leaving usage context somewhat implied rather than clearly defined.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Open a URL in the designer's headed Chromium (launches it if not running). Use this before designer_pick.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | URL to navigate to |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It discloses key behavioral traits: it opens a URL, launches Chromium if not running, and is intended as a preparatory step. However, it lacks details on error handling, timeouts, or what happens if the URL is invalid, which are important for a tool that interacts with a browser.
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 extremely concise and front-loaded, with two sentences that efficiently convey the action, conditional behavior, and usage context. Every sentence earns its place by providing essential information without redundancy or fluff.
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 the tool's low complexity (1 parameter, no output schema, no annotations), the description is mostly complete. It covers purpose, usage, and key behavior. However, it could improve by mentioning potential side effects (e.g., browser window focus) or error scenarios, slightly reducing completeness for a tool that launches external processes.
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 schema fully documenting the 'url' parameter. The description does not add any meaning beyond the schema (e.g., URL format examples or constraints), so it meets the baseline of 3 where the schema does the heavy lifting without extra value from the description.
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 clearly states the specific action ('Open a URL') and the target resource ('in the designer's headed Chromium'), including the conditional behavior ('launches it if not running'). It distinguishes from siblings by mentioning designer_pick as a subsequent step, showing awareness of the tool's role in the workflow.
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 explicitly provides when-to-use guidance by stating 'Use this before designer_pick,' establishing a clear sequence in the workflow. This directly addresses when to use this tool versus alternatives (like designer_screenshot or designer_close) by positioning it as a prerequisite step.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Activate the picker in the designer browser. Three modes: element — user clicks one element; returns { selector, tag, classes, text, html, rect, source, screenshot_path } area — user drags a marquee; returns { rect, elements: [{selector, source, rect, ...}], screenshot_path } draw — user ink-annotates with a red pen, Enter to finish; returns { strokes, viewport, screenshot_path (strokes only), viewport_screenshot_path (full view with drawings) } Esc cancels in any mode. screenshot_path / viewport_screenshot_path point to PNGs in /tmp; open with the Read tool.
| Name | Required | Description | Default |
|---|---|---|---|
| mode | No | element (default) = click one, area = drag marquee, draw = freeform pen |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the interactive nature of the tool (user clicks/drags/annotates), cancellation behavior, and output file handling (PNGs in /tmp). However, it doesn't mention potential side effects like browser focus changes or performance considerations.
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 efficiently structured with bullet-like formatting for the three modes, each clearly explaining the user interaction and return values. Every sentence adds essential information about functionality, cancellation, or output handling with zero wasted text.
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 tool with no annotations and no output schema, the description provides comprehensive context about the interactive process, return data structures, and file outputs. The only minor gap is lack of explicit mention about whether this tool requires specific browser state or permissions.
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?
The schema has 100% description coverage with clear enum values and descriptions. The description adds significant value by detailing what each mode returns (specific data structures like selector, rect, strokes, etc.) and operational differences between modes, going well beyond the schema's basic mode definitions.
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 clearly states the tool's purpose: 'Activate the picker in the designer browser' with three specific modes (element, area, draw). It distinguishes from siblings like designer_close, designer_open, and designer_screenshot by focusing on interactive element/area selection and annotation rather than basic browser operations or screenshot capture.
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 provides explicit guidance on when to use each mode: element for clicking one element, area for dragging a marquee, and draw for freeform pen annotation. It also specifies 'Esc cancels in any mode' and mentions using the Read tool to open resulting PNGs, giving clear operational context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Screenshot the current page or a specific element selector. Returns { path, bytes } — a filesystem path to a PNG in /tmp that you can Read with the Read tool.
| Name | Required | Description | Default |
|---|---|---|---|
| selector | No | Optional CSS selector |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden and effectively discloses key behaviors: it returns a filesystem path to a PNG in /tmp, specifies the output format ({ path, bytes }), and mentions a follow-up action (Read tool). However, it lacks details on potential errors or limitations.
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 front-loaded with the core purpose, followed by essential details on output and usage, with every sentence earning its place and no wasted words.
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 the tool's moderate complexity (screenshot functionality with one optional parameter) and no output schema, the description is mostly complete, covering purpose, output, and a follow-up action, though it could include more on error 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?
The schema description coverage is 100%, so the baseline is 3. The description adds minimal value beyond the schema by implying the selector is optional and used for targeting elements, but does not provide additional syntax or format details.
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 clearly states the verb ('Screenshot') and resource ('the current page or a specific element selector'), distinguishing it from sibling tools like designer_close, designer_open, and designer_pick by specifying its unique screenshot functionality.
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 provides clear context for usage by specifying 'the current page or a specific element selector' and mentions an alternative action ('Read with the Read tool'), but does not explicitly state when not to use it or compare directly to sibling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
v0.1.0designer_closedesigner_opendesigner_pickdesigner_screenshotScored across 4 tools
Each tool has a clearly distinct purpose with no overlap: open launches the browser, pick activates the picker with specific modes, screenshot captures images, and close terminates the session. The descriptions clearly differentiate their functions, eliminating any ambiguity in tool selection.
All tool names follow a consistent 'designer_' prefix with descriptive action suffixes (open, pick, screenshot, close), using snake_case uniformly. This predictable pattern makes the tool set easy to navigate and understand at a glance.
With 4 tools, this server is well-scoped for its purpose of browser-based design interactions. Each tool earns its place by covering essential operations: launching, picking elements, capturing screenshots, and cleaning up, without being overly sparse or bloated.
The tool set provides complete lifecycle coverage for the designer domain: it supports opening the browser, interactive element selection, screenshot capture, and proper resource closure. There are no obvious gaps, as all core workflows from initiation to termination are addressed effectively.
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