fix(cli): every mcp subcommand prints usage for -h/--help and mcp import refuses arguments

Only add intercepted the flag, so mcp import --help ran the import and mcp remove --help looked up a server named --help. The dispatcher now answers the flag once, before choosing a subcommand; a flag later on the line still reaches the command, as in mcp add name -- cmd --help.

desktop/electron/src/host.js

@@ -28,7 +28,7 @@ class HostStartError extends Error {
 function start(binary, args, { onStderr, onExit, onAct, onSlow, systemLanguage, timeoutMs = HANDSHAKE_TIMEOUT_MS } = {}) {
   const env = { ...process.env };
   if (systemLanguage) env.REASONIX_SYSTEM_LANG = systemLanguage;
-  const child = spawn(binary, args, { stdio: ["pipe", "pipe", "pipe"], env });
+  const child = spawn(binary, args, { stdio: ["pipe", "pipe", "pipe"], env, windowsHide: true });
   child.stderr.setEncoding("utf8");
   if (onStderr) child.stderr.on("data", onStderr);
   if (onExit) child.on("exit", onExit);

desktop/electron/src/instance.js

@@ -6,9 +6,9 @@ const { execFileSync } = require("node:child_process");
 // one Studio, canonicalized where it lives. The kernel answers it, because the
 // home is resolved from an environment and a platform default this process
 // does not own.
-function instanceID(binary) {
+function instanceID(binary, run = execFileSync) {
   try {
-    return execFileSync(binary, ["-instance-id"], { encoding: "utf8", timeout: 10000 }).trim();
+    return run(binary, ["-instance-id"], { encoding: "utf8", timeout: 10000, windowsHide: true }).trim();
   } catch {
     // A kernel that cannot be run at all is a launch that is going to fail with
     // a better message in a moment. Refusing to start here would report it as

desktop/electron/test/unit.mjs

@@ -625,7 +625,7 @@ test("Windows is given the format it reads the small sizes from", () => {
   assert.equal(iconFile("linux"), "icon.png");
 });
 
-const { profileFor } = require("../src/instance.js");
+const { profileFor, instanceID } = require("../src/instance.js");
 
 // Two homes are two Studios, and the profile is what carries that into the
 // platform's own lock. Sharing one would make the second launch look like a
@@ -641,6 +641,14 @@ test("each instance gets a profile of its own", () => {
   assert.equal(profileFor(base, ""), base);
 });
 
+test("the instance probe runs the kernel without a console window of its own", () => {
+  let options;
+  const run = (binary, args, opts) => { options = { binary, args, opts }; return "abc123\n"; };
+  assert.equal(instanceID("host", run), "abc123");
+  assert.deepEqual(options.args, ["-instance-id"]);
+  assert.equal(options.opts.windowsHide, true);
+});
+
 // A program that cannot be started emits "error" and never "exit". Waiting for
 // the handshake instead spent the full timeout and then blamed the kernel for
 // saying nothing, which is where the launch failure on Windows hid: go build

internal/frontend/cli/mcp.go

@@ -33,6 +33,10 @@ func mcpCommand(args []string) int {
 		mcpUsage()
 		return 2
 	}
+	if len(args) > 1 && (args[1] == "-h" || args[1] == "--help") {
+		mcpUsage()
+		return 0
+	}
 	switch args[0] {
 	case "list", "ls":
 		if len(args) > 1 {
@@ -41,10 +45,6 @@ func mcpCommand(args []string) int {
 		}
 		return mcpList()
 	case "add":
-		if len(args) > 1 && (args[1] == "-h" || args[1] == "--help") {
-			mcpUsage()
-			return 0
-		}
 		return mcpAddCLI(args[1:])
 	case "get":
 		return mcpGetCLI(args[1:])
@@ -64,6 +64,10 @@ func mcpCommand(args []string) int {
 	case "update":
 		return mcpUpdateCLI(args[1:])
 	case "import":
+		if len(args) > 1 {
+			fmt.Fprintf(os.Stderr, "mcp import: unexpected argument %q\n", args[1])
+			return 2
+		}
 		return mcpImportCLI()
 	case "browse", "search":
 		return mcpBrowseCLI(args[1:])

internal/frontend/cli/mcp_help_test.go

@@ -33,3 +33,35 @@ func TestMCPListAndGetRejectExtraArguments(t *testing.T) {
 		}
 	}
 }
+
+func TestMCPHelpFlagPrintsUsageForEverySubcommandAndRunsNothing(t *testing.T) {
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	t.Setenv("USERPROFILE", home)
+	t.Setenv("REASONIX_HOME", home)
+	for _, sub := range []string{"list", "ls", "add", "get", "remove", "rm", "enable", "disable", "retry", "connect", "trust", "auth", "authorize", "update", "import", "browse", "search", "install"} {
+		for _, flag := range []string{"--help", "-h"} {
+			var code int
+			stdout, stderr := captureCLIOutput(t, func() {
+				code = Run([]string{"mcp", sub, flag}, "test")
+			})
+			if code != 0 || !strings.Contains(stdout, "reasonix mcp") || stderr != "" || strings.Contains(stdout, "imported") {
+				t.Errorf("mcp %s %s: exit %d, want 0 with usage only\nstdout:\n%s\nstderr:\n%s", sub, flag, code, stdout, stderr)
+			}
+		}
+	}
+}
+
+func TestMCPImportRejectsArgumentsInsteadOfImporting(t *testing.T) {
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	t.Setenv("USERPROFILE", home)
+	t.Setenv("REASONIX_HOME", home)
+	var code int
+	stdout, stderr := captureCLIOutput(t, func() {
+		code = Run([]string{"mcp", "import", "--nope"}, "test")
+	})
+	if code != 2 || stdout != "" || stderr == "" {
+		t.Fatalf("mcp import --nope exited %d, want 2 with an error\nstdout:\n%s\nstderr:\n%s", code, stdout, stderr)
+	}
+}

release-notes/studio/unreleased/mcp-help-flag-runs-nothing.md

@@ -0,0 +1,10 @@
+## 修复
+
+- 修复命令行里 `reasonix mcp import --help`（以及 `mcp remove --help` 等其他子命令）不会显示用法，反而把 `--help` 当成参数真的去执行：`import` 会直接改写 MCP 配置。现在所有 `reasonix mcp` 子命令的 `--help` / `-h` 都只打印用法并退出，什么都不改；`mcp import` 带多余参数时会报错而不是照常导入（#15022）。
+
+---
+<!-- lang:en -->
+
+## Fixed
+
+- `reasonix mcp import --help` (and `--help` on the other `mcp` subcommands) did not print usage and ran the command with `--help` as an argument, so `import` rewrote the MCP configuration. Every `reasonix mcp` subcommand now prints usage for `--help` / `-h` and changes nothing, and `mcp import` refuses extra arguments instead of importing (#15022).

release-notes/studio/unreleased/windows-launch-console-flash.md

@@ -0,0 +1,10 @@
+## 修复
+
+- 修复 Windows 上每次启动 Reasonix Studio 都会先闪一下黑色控制台窗口的问题：启动时用来确认"是不是同一个 Studio"的内核探测，以及启动内核本身，现在都隐藏控制台窗口（#15016）。
+
+---
+<!-- lang:en -->
+
+## Fixed
+
+- On Windows, launching Reasonix Studio no longer flashes a console window first: the kernel probe that tells whether this is the same Studio, and the kernel launch itself, now run with their console hidden (#15016).