feat: browser_mcp — servidor MCP de control de navegador CDP (33 tools + pool de conexiones)

2026-06-06 10:57:13 +02:00
commit 6ecaf9a969
15 changed files with 1668 additions and 0 deletions
@@ -0,0 +1,110 @@
+package main
+
+import (
+	"context"
+
+	"github.com/mark3labs/mcp-go/mcp"
+	"github.com/mark3labs/mcp-go/server"
+
+	"fn-registry/functions/browser"
+)
+
+const htmlMax = 200_000
+
+// registerReadTools wires page_get_html, page_eval_js (MUTA), page_screenshot.
+func registerReadTools(s *server.MCPServer, d *deps) {
+	s.AddTool(pageGetHTMLTool(), mcp.NewTypedToolHandler(d.handlePageGetHTML))
+	s.AddTool(pageScreenshotTool(), mcp.NewTypedToolHandler(d.handlePageScreenshot))
+
+	if !d.readOnly {
+		s.AddTool(pageEvalJSTool(), mcp.NewTypedToolHandler(d.handlePageEvalJS))
+	}
+}
+
+// ---- page_get_html ----
+
+type pageGetHTMLArgs struct {
+	Port int `json:"port"`
+}
+
+func pageGetHTMLTool() mcp.Tool {
+	return mcp.NewTool("page_get_html",
+		mcp.WithDescription("Return the current page's full serialized HTML (outerHTML). Truncated to 200000 chars."),
+		mcp.WithNumber("port", mcp.Description("CDP port. Default 9222.")),
+	)
+}
+
+func (d *deps) handlePageGetHTML(_ context.Context, _ mcp.CallToolRequest, a pageGetHTMLArgs) (*mcp.CallToolResult, error) {
+	var html string
+	err := d.withConn(portOr(a.Port), func(c *browser.CDPConn) error {
+		var e error
+		html, e = browser.CdpGetHTML(c)
+		return e
+	})
+	if err != nil {
+		return mcp.NewToolResultError(err.Error()), nil
+	}
+	return mcp.NewToolResultText(truncate(html, htmlMax)), nil
+}
+
+// ---- page_eval_js (MUTA) ----
+
+type pageEvalJSArgs struct {
+	Port       int    `json:"port"`
+	Expression string `json:"expression"`
+}
+
+func pageEvalJSTool() mcp.Tool {
+	return mcp.NewTool("page_eval_js",
+		mcp.WithDescription("Evaluate a JavaScript expression in the page context via Runtime.evaluate. Returns the stringified result."),
+		mcp.WithNumber("port", mcp.Description("CDP port. Default 9222.")),
+		mcp.WithString("expression", mcp.Required(), mcp.Description("JavaScript expression to evaluate.")),
+	)
+}
+
+func (d *deps) handlePageEvalJS(_ context.Context, _ mcp.CallToolRequest, a pageEvalJSArgs) (*mcp.CallToolResult, error) {
+	if a.Expression == "" {
+		return mcp.NewToolResultError("expression is required"), nil
+	}
+	var res string
+	err := d.withConn(portOr(a.Port), func(c *browser.CDPConn) error {
+		var e error
+		res, e = browser.CdpEvaluate(c, a.Expression)
+		return e
+	})
+	if err != nil {
+		return mcp.NewToolResultError(err.Error()), nil
+	}
+	return mcp.NewToolResultText(truncate(res, htmlMax)), nil
+}
+
+// ---- page_screenshot ----
+
+type pageScreenshotArgs struct {
+	Port     int    `json:"port"`
+	Path     string `json:"path"`
+	FullPage bool   `json:"full_page"`
+}
+
+func pageScreenshotTool() mcp.Tool {
+	return mcp.NewTool("page_screenshot",
+		mcp.WithDescription("Capture a screenshot of the current page and write it to a local path (.png/.jpg)."),
+		mcp.WithNumber("port", mcp.Description("CDP port. Default 9222.")),
+		mcp.WithString("path", mcp.Required(), mcp.Description("Output file path (.png or .jpg).")),
+		mcp.WithBoolean("full_page", mcp.Description("Capture the full scroll height instead of just the viewport.")),
+	)
+}
+
+func (d *deps) handlePageScreenshot(_ context.Context, _ mcp.CallToolRequest, a pageScreenshotArgs) (*mcp.CallToolResult, error) {
+	if a.Path == "" {
+		return mcp.NewToolResultError("path is required"), nil
+	}
+	opts := browser.CdpScreenshotOpts{FullPage: a.FullPage}
+	err := d.withConn(portOr(a.Port), func(c *browser.CDPConn) error {
+		return browser.CdpScreenshot(c, a.Path, opts)
+	})
+	if err != nil {
+		return mcp.NewToolResultError(err.Error()), nil
+	}
+	return mcp.NewToolResultText("screenshot saved to " + a.Path), nil
+}