Fix long-lived servers mounting volumes as read-only

pkg/gateway/clientpool.go

@@ -352,7 +352,10 @@ func (cp *clientPool) argsAndEnv(serverConfig *catalog.ServerConfig, readOnly *b
 			continue
 		}
 
-		if readOnly != nil && *readOnly && !strings.HasSuffix(mount, ":ro") {
+		// For long-lived servers, never mount volumes as read-only
+		// because the container will be shared across multiple tool calls
+		isLongLived := serverConfig.Spec.LongLived || cp.LongLived
+		if !isLongLived && readOnly != nil && *readOnly && !strings.HasSuffix(mount, ":ro") {
 			args = append(args, "-v", mount+":ro")
 		} else {
 			args = append(args, "-v", mount)

pkg/gateway/clientpool_test.go

@@ -160,6 +160,42 @@ user: "1001:2002"
 	assert.Empty(t, env)
 }
 
+func TestApplyConfigLongLivedIgnoresReadOnly(t *testing.T) {
+	catalogYAML := `
+longLived: true
+volumes:
+  - '/local/data:/data'
+  `
+
+	args, env := argsAndEnv(t, "longlived", catalogYAML, "", nil, readOnly())
+
+	// Even though readOnly is true, volumes should NOT have :ro appended
+	// because long-lived servers share containers across multiple tool calls
+	assert.Equal(t, []string{
+		"run", "--rm", "-i", "--init", "--security-opt", "no-new-privileges", "--cpus", "1", "--memory", "2Gb", "--pull", "never",
+		"-l", "docker-mcp=true", "-l", "docker-mcp-tool-type=mcp", "-l", "docker-mcp-name=longlived", "-l", "docker-mcp-transport=stdio",
+		"-v", "/local/data:/data",
+	}, args)
+	assert.Empty(t, env)
+}
+
+func TestApplyConfigShortLivedRespectsReadOnly(t *testing.T) {
+	catalogYAML := `
+volumes:
+  - '/local/data:/data'
+  `
+
+	args, env := argsAndEnv(t, "shortlived", catalogYAML, "", nil, readOnly())
+
+	// Short-lived servers should respect readOnly flag
+	assert.Equal(t, []string{
+		"run", "--rm", "-i", "--init", "--security-opt", "no-new-privileges", "--cpus", "1", "--memory", "2Gb", "--pull", "never",
+		"-l", "docker-mcp=true", "-l", "docker-mcp-tool-type=mcp", "-l", "docker-mcp-name=shortlived", "-l", "docker-mcp-transport=stdio",
+		"-v", "/local/data:/data:ro",
+	}, args)
+	assert.Empty(t, env)
+}
+
 func argsAndEnv(t *testing.T, name, catalogYAML, configYAML string, secrets map[string]string, readOnly *bool) ([]string, []string) {
 	t.Helper()