diff --git a/telemetry/trace/trace.go b/telemetry/trace/trace.go
index fe277fb9ec..4b0ce4999d 100644
--- a/telemetry/trace/trace.go
+++ b/telemetry/trace/trace.go
@@ -30,6 +30,7 @@ import (
 	"go.opentelemetry.io/otel/trace/noop"
 
 	itelemetry "trpc.group/trpc-go/trpc-agent-go/internal/telemetry"
+	"trpc.group/trpc-go/trpc-agent-go/platform"
 )
 
 // TracerProvider is the global tracer TracerProvider for telemetry.
@@ -248,13 +249,20 @@ func parseEndpointURL(endpointURL string) (endpoint, urlPath string, err error)
 
 	u, err := url.Parse(endpointURL)
 	if err != nil {
-		return "", "", fmt.Errorf("failed to parse URL %q: %w", originalURL, err)
+		return "", "", redactedTraceConfigError{
+			msg: fmt.Sprintf(
+				"failed to parse URL %q: %s",
+				redactTraceConfigValue(originalURL),
+				redactTraceConfigValue(err.Error()),
+			),
+			err: err,
+		}
 	}
 
 	// Extract host:port
 	endpoint = u.Host
 	if endpoint == "" {
-		return "", "", fmt.Errorf("no host found in URL %q", originalURL)
+		return "", "", fmt.Errorf("no host found in URL %q", redactTraceConfigValue(originalURL))
 	}
 
 	// Extract path
@@ -305,7 +313,7 @@ func initHTTPTracerProvider(ctx context.Context, res *resource.Resource, opts *o
 		// Parse the full URL to extract host:port and path components
 		endpoint, urlPath, err := parseEndpointURL(opts.tracesEndpointURL)
 		if err != nil {
-			return nil, fmt.Errorf("failed to parse endpoint URL %q: %w", opts.tracesEndpointURL, err)
+			return nil, fmt.Errorf("failed to parse endpoint URL %q: %w", redactTraceConfigValue(opts.tracesEndpointURL), err)
 		}
 		otelOpts = append(otelOpts,
 			otlptracehttp.WithEndpoint(endpoint),
@@ -320,6 +328,50 @@ func initHTTPTracerProvider(ctx context.Context, res *resource.Resource, opts *o
 	return setupTracerProvider(res, traceExporter), nil
 }
 
+func redactTraceConfigValue(value string) string {
+	redactor, err := platform.NewRedactor()
+	if err != nil {
+		return "<redacted>"
+	}
+	return redactTraceConfigURLUserinfo(redactor.Redact(value))
+}
+
+type redactedTraceConfigError struct {
+	msg string
+	err error
+}
+
+func (e redactedTraceConfigError) Error() string {
+	return e.msg
+}
+
+func (e redactedTraceConfigError) Unwrap() error {
+	return e.err
+}
+
+func redactTraceConfigURLUserinfo(value string) string {
+	authorityStart := 0
+	schemeIndex := strings.Index(value, "://")
+	if schemeIndex >= 0 {
+		authorityStart = schemeIndex + len("://")
+	}
+	if authorityStart >= len(value) {
+		return value
+	}
+	authorityEnd := len(value)
+	for _, delimiter := range []string{"/", "?", "#"} {
+		if index := strings.Index(value[authorityStart:], delimiter); index >= 0 {
+			authorityEnd = min(authorityEnd, authorityStart+index)
+		}
+	}
+	authority := value[authorityStart:authorityEnd]
+	at := strings.LastIndex(authority, "@")
+	if at < 0 {
+		return value
+	}
+	return value[:authorityStart] + "****" + value[authorityStart+at:]
+}
+
 // setupTracerProvider sets up the tracer provider with the given resource and exporter.
 func setupTracerProvider(res *resource.Resource, traceExporter sdktrace.SpanExporter) func(context.Context) error {
 	// Register the trace exporter with a TracerProvider, using a batch
diff --git a/telemetry/trace/trace_test.go b/telemetry/trace/trace_test.go
index aace9d200a..7b2b7b3ddf 100644
--- a/telemetry/trace/trace_test.go
+++ b/telemetry/trace/trace_test.go
@@ -12,6 +12,7 @@ package trace
 import (
 	"context"
 	"os"
+	"strings"
 	"testing"
 
 	"go.opentelemetry.io/otel/attribute"
@@ -158,6 +159,39 @@ func TestStartHTTP_InvalidEndpointURL(t *testing.T) {
 	}
 }
 
+func TestStartHTTP_InvalidEndpointURLRedactsSensitiveConfig(t *testing.T) {
+	for _, endpointURL := range []string{
+		"http://user:password@/bad?api_key=sk-1234567890abcdef",
+		"user:password@/bad?api_key=sk-1234567890abcdef",
+		"http://user:password@%zz/bad?api_key=sk-1234567890abcdef",
+		"user:password@%zz/bad?api_key=sk-1234567890abcdef",
+	} {
+		t.Run(endpointURL, func(t *testing.T) {
+			ctx := context.Background()
+			_, err := Start(ctx,
+				WithProtocol("http"),
+				WithEndpoint("localhost:4318"),
+				WithEndpointURL(endpointURL),
+			)
+			if err == nil {
+				t.Fatalf("expected error from invalid endpoint URL")
+			}
+			for _, leaked := range []string{
+				"user:password",
+				"password",
+				"sk-1234567890abcdef",
+			} {
+				if strings.Contains(err.Error(), leaked) {
+					t.Fatalf("trace config error leaked %q: %v", leaked, err)
+				}
+			}
+			if !strings.Contains(err.Error(), "failed to parse endpoint URL") {
+				t.Fatalf("expected endpoint context in error, got %v", err)
+			}
+		})
+	}
+}
+
 func TestStartHTTP_DefaultNoEnv_NoEndpoint(t *testing.T) {
 	// ensure env empty
 	origTrace := os.Getenv("OTEL_EXPORTER_OTLP_TRACES_ENDPOINT")