diff --git a/d2cli/help.go b/d2cli/help.go
index 010118c22..6d1ea0567 100644
--- a/d2cli/help.go
+++ b/d2cli/help.go
@@ -39,7 +39,7 @@ Subcommands:
   %[1]s layout [name] - Display long help for a particular layout engine, including its configuration options
   %[1]s themes - Lists available themes
   %[1]s fmt file.d2 ... - Format passed files
-  %[1]s play file.d2 - Opens the file in playground
+	%[1]s play file.d2 - Opens the file in playground, an online web viewer (https://play.d2lang.com)
 
 See more docs and the source code at https://oss.terrastruct.com/d2.
 Hosted icons at https://icons.terrastruct.com.
diff --git a/d2cli/main.go b/d2cli/main.go
index 7823db6b8..de4dded2a 100644
--- a/d2cli/main.go
+++ b/d2cli/main.go
@@ -155,7 +155,7 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 		case "fmt":
 			return fmtCmd(ctx, ms)
 		case "play":
-			return playSubcommand(ctx, ms)
+			return playCmd(ctx, ms)
 		case "version":
 			if len(ms.Opts.Flags.Args()) > 1 {
 				return xmain.UsageErrorf("version subcommand accepts no arguments")
diff --git a/d2cli/play.go b/d2cli/play.go
index 9bbd6cf25..f32590576 100644
--- a/d2cli/play.go
+++ b/d2cli/play.go
@@ -3,6 +3,7 @@ package d2cli
 import (
 	"context"
 	"fmt"
+	"io"
 	"os"
 
 	"oss.terrastruct.com/d2/lib/urlenc"
@@ -10,9 +11,9 @@ import (
 	"oss.terrastruct.com/util-go/xmain"
 )
 
-func playSubcommand(ctx context.Context, ms *xmain.State) error {
+func playCmd(ctx context.Context, ms *xmain.State) error {
 	if len(ms.Opts.Flags.Args()) != 2 {
-		return xmain.UsageErrorf("play must be passed one file to open")
+		return xmain.UsageErrorf("play must be passed one argument: either a filepath or '-' for stdin")
 	}
 	filepath := ms.Opts.Flags.Args()[1]
 
@@ -33,7 +34,7 @@ func playSubcommand(ctx context.Context, ms *xmain.State) error {
 		sketchNumber = 0
 	}
 
-	fileRaw, err := readFile(filepath)
+	fileRaw, err := readInput(filepath)
 	if err != nil {
 		return err
 	}
@@ -43,17 +44,24 @@ func playSubcommand(ctx context.Context, ms *xmain.State) error {
 		return err
 	}
 
-	url := fmt.Sprintf("https://play.d2lang.com/?l=&script=%s&sketch=%d&theme=%d&", encoded, sketchNumber, theme)
+	url := fmt.Sprintf("https://play.d2lang.com/?script=%s&sketch=%d&theme=%d&", encoded, sketchNumber, theme)
 	openBrowser(ctx, ms, url)
 	return nil
 }
 
-func readFile(filepath string) (string, error) {
+func readInput(filepath string) (string, error) {
+	if filepath == "-" {
+		data, err := io.ReadAll(os.Stdin)
+		if err != nil {
+			return "", fmt.Errorf("error reading from stdin: %w", err)
+		}
+		return string(data), nil
+	}
+
 	data, err := os.ReadFile(filepath)
 	if err != nil {
 		return "", xmain.UsageErrorf(err.Error())
 	}
-
 	return string(data), nil
 }