diff --git a/install.ps1 b/install.ps1
index 11fbab8..c3d073c 100644
--- a/install.ps1
+++ b/install.ps1
@@ -498,6 +498,8 @@ if ($LASTEXITCODE -eq 0) {
 # key above cannot authorize it. Do the browser sign-in now, while the user is
 # still here, rather than surprising them mid-session.
 if (Confirm-Step 'Sign in to the qBraid MCP now? (opens a browser)' 'y') {
+    # Unlike the piped bash path, `iex` keeps the console attached, so the
+    # OAuth prompt can read the redirect URL directly.
     claude mcp login $McpName
     if ($LASTEXITCODE -ne 0) { Warn "MCP sign-in did not complete. Run ``claude mcp login $McpName`` later." }
 } else {
diff --git a/install.sh b/install.sh
index ac13858..0b84a2f 100755
--- a/install.sh
+++ b/install.sh
@@ -716,7 +716,11 @@ fi
 # still here, rather than surprising them mid-session.
 if [ -n "$TTY" ]; then
   if confirm "Sign in to the qBraid MCP now? (opens a browser)" y; then
-    claude mcp login "$MCP_NAME" \
+    # `claude mcp login` needs a real terminal to take the redirect URL. Under
+    # `curl … | bash` this script's stdin IS the pipe, so it must be handed the
+    # terminal explicitly — otherwise sign-in always fails with
+    # "stdin isn't a terminal".
+    claude mcp login "$MCP_NAME" < "$TTY" \
       || warn "MCP sign-in did not complete. Run \`claude mcp login $MCP_NAME\` later."
   else
     warn "skipped. Run \`claude mcp login $MCP_NAME\` when you want the qBraid tools."