diff --git a/internal/temporalcli/commands.server_test.go b/internal/temporalcli/commands.server_test.go
index 26b92cf60..98438875b 100644
--- a/internal/temporalcli/commands.server_test.go
+++ b/internal/temporalcli/commands.server_test.go
@@ -2,6 +2,7 @@ package temporalcli_test
 
 import (
 	"context"
+	"fmt"
 	"net"
 	"os"
 	"path/filepath"
@@ -139,58 +140,104 @@ func startDevServerAndRunSimpleTest(t *testing.T, args []string, dialAddress str
 }
 
 func TestServer_StartDev_ConcurrentStarts(t *testing.T) {
-	startOne := func() {
-		h := NewCommandHarness(t)
-		defer h.Close()
+	h := NewCommandHarness(t)
+
+	startOne := func() error {
+		ctx, cancel := context.WithCancel(t.Context())
+		defer cancel()
 
 		// Start in background, then wait for client to be able to connect
 		port := strconv.Itoa(devserver.MustGetFreePort("127.0.0.1"))
 		httpPort := strconv.Itoa(devserver.MustGetFreePort("127.0.0.1"))
 		resCh := make(chan *CommandResult, 1)
 		go func() {
-			resCh <- h.Execute("server", "start-dev", "-p", port, "--http-port", httpPort, "--headless", "--log-level", "never")
+			resCh <- h.ExecuteWithContext(ctx, "server", "start-dev", "-p", port, "--http-port", httpPort, "--headless", "--log-level", "never")
 		}()
 
 		// Try to connect for a bit while checking for error
 		var cl client.Client
-		h.EventuallyWithT(func(t *assert.CollectT) {
+		var lastDialErr error
+		ticker := time.NewTicker(200 * time.Millisecond)
+		defer ticker.Stop()
+		timeout := time.NewTimer(3 * time.Second)
+		defer timeout.Stop()
+
+	waitForServer:
+		for {
 			select {
 			case res := <-resCh:
-				require.NoError(t, res.Err)
-				require.Fail(t, "got early server result")
-			default:
+				return concurrentStartCommandResultError("got early server result", res)
+			case <-ticker.C:
+				var err error
+				cl, err = client.Dial(client.Options{HostPort: "127.0.0.1:" + port})
+				if err == nil {
+					break waitForServer
+				}
+				lastDialErr = err
+			case <-timeout.C:
+				break waitForServer
 			}
-			var err error
-			cl, err = client.Dial(client.Options{HostPort: "127.0.0.1:" + port, Logger: testLogger{t: h.t}})
-			assert.NoError(t, err)
-		}, 3*time.Second, 200*time.Millisecond)
+		}
+		if cl == nil {
+			cancel()
+			select {
+			case <-time.After(20 * time.Second):
+				return fmt.Errorf("server was not reachable after 3 seconds: %w; also did not clean up within 20 seconds", lastDialErr)
+			case res := <-resCh:
+				if res.Err != nil {
+					return fmt.Errorf(
+						"server was not reachable after 3 seconds: %w; cleanup failed: %w",
+						lastDialErr,
+						res.Err,
+					)
+				}
+				return fmt.Errorf("server was not reachable after 3 seconds: %w", lastDialErr)
+			}
+		}
 		defer cl.Close()
 
 		// Send an interrupt by cancelling context
-		h.CancelContext()
+		cancel()
 
 		select {
 		case <-time.After(20 * time.Second):
-			h.Fail("didn't cleanup after 20 seconds")
+			return fmt.Errorf("didn't cleanup after 20 seconds")
 		case res := <-resCh:
-			h.NoError(res.Err)
+			if res.Err != nil {
+				return concurrentStartCommandResultError("server returned error", res)
+			}
 		}
+		return nil
 	}
 
-	// Start 40 dev server instances, with 8 concurrent executions
+	// Start 40 dev server instances, with 6 concurrent executions.
 	instanceCounter := atomic.Int32{}
 	instanceCounter.Store(40)
+	errCh := make(chan error, 40)
 	wg := &sync.WaitGroup{}
 	for i := 0; i < 6; i++ {
 		wg.Add(1)
 		go func() {
+			defer wg.Done()
 			for instanceCounter.Add(-1) >= 0 {
-				startOne()
+				if err := startOne(); err != nil {
+					errCh <- err
+				}
 			}
-			wg.Done()
 		}()
 	}
 	wg.Wait()
+	close(errCh)
+	for err := range errCh {
+		require.NoError(t, err)
+	}
+}
+
+func concurrentStartCommandResultError(msg string, res *CommandResult) error {
+	if res.Err != nil {
+		return fmt.Errorf("%s: %w (stdout: %q, stderr: %q)", msg, res.Err, res.Stdout.String(), res.Stderr.String())
+	}
+	return fmt.Errorf("%s (stdout: %q, stderr: %q)", msg, res.Stdout.String(), res.Stderr.String())
 }
 
 func TestServer_StartDev_WithSearchAttributes(t *testing.T) {
diff --git a/internal/temporalcli/commands_test.go b/internal/temporalcli/commands_test.go
index 1b1a18e51..8e9bb1f2f 100644
--- a/internal/temporalcli/commands_test.go
+++ b/internal/temporalcli/commands_test.go
@@ -151,11 +151,23 @@ type CommandResult struct {
 }
 
 func (h *CommandHarness) Execute(args ...string) *CommandResult {
+	ctx, cancel := context.WithCancel(h.Context)
+	h.t.Cleanup(cancel)
+	defer cancel()
+	return h.execute(ctx, &h.Stdin, args...)
+}
+
+func (h *CommandHarness) ExecuteWithContext(ctx context.Context, args ...string) *CommandResult {
+	var stdin bytes.Buffer
+	return h.execute(ctx, &stdin, args...)
+}
+
+func (h *CommandHarness) execute(ctx context.Context, stdin io.Reader, args ...string) *CommandResult {
 	// Copy options, update as needed
 	res := &CommandResult{}
 	options := h.Options
 	// Set stdio
-	options.Stdin = &h.Stdin
+	options.Stdin = stdin
 	options.Stdout = &res.Stdout
 	options.Stderr = &res.Stderr
 	// Set args
@@ -175,10 +187,6 @@ func (h *CommandHarness) Execute(args ...string) *CommandResult {
 		res.Err = err
 	}
 
-	// Run
-	ctx, cancel := context.WithCancel(h.Context)
-	h.t.Cleanup(cancel)
-	defer cancel()
 	h.t.Logf("Calling: %v", strings.Join(args, " "))
 	temporalcli.Execute(ctx, options)
 	if res.Stdout.Len() > 0 {