fix: restore workflow and ultracode on the released binary

packages/coding-agent/package.json

@@ -39,6 +39,7 @@
 		"@step-harness/providers": "^0.84.4",
 		"@step-harness/pi-tui": "^0.84.4",
 		"@step-harness/config": "workspace:*",
+		"@jitl/quickjs-singlefile-mjs-release-sync": "0.32.0",
 		"@modelcontextprotocol/sdk": "1.27.1",
 		"@silvia-odwyer/photon-node": "0.3.4",
 		"chalk": "5.6.2",
@@ -51,6 +52,7 @@
 		"jiti": "2.7.0",
 		"minimatch": "10.2.5",
 		"proper-lockfile": "4.1.2",
+		"quickjs-emscripten-core": "0.32.0",
 		"semver": "7.8.0",
 		"smol-toml": "1.8.0",
 		"typebox": "1.3.7",

packages/coding-agent/src/features/workflow/index.ts

@@ -31,7 +31,12 @@ export {
 	workflowHash,
 } from "./journal.ts";
 export { formatWorkflowStatus, listSavedWorkflows, listWorkflowRuns, WorkflowProgressStore } from "./progress.ts";
-export { WorkflowRuntime, WorkflowSchemaError, workflowToolResult } from "./runtime.ts";
+export {
+	defaultWorkflowVmExecutor,
+	WorkflowRuntime,
+	WorkflowSchemaError,
+	workflowToolResult,
+} from "./runtime.ts";
 export { validateWorkflowSchema } from "./schema.ts";
 export {
 	createStepWorkflowExtension,
@@ -49,3 +54,4 @@ export {
 } from "./tool-profile.ts";
 export type * from "./types.ts";
 export { isIsolatedVmAvailable, loadIsolatedVm, runInIsolatedVm, WORKFLOW_MAX_SCRIPT_BYTES } from "./vm.ts";
+export { isQuickJsVmAvailable, runInQuickJs } from "./vm-quickjs.ts";

packages/coding-agent/src/features/workflow/registration-gate.ts

@@ -7,12 +7,12 @@ function envFlag(value: string | undefined): boolean {
 
 export type WorkflowRegistrationDecision =
 	| { enabled: true }
-	| { enabled: false; reason: "not-enabled" | "disabled-by-env" | "vm-unavailable" | "vm-unsupported-runtime" };
+	| { enabled: false; reason: "not-enabled" | "disabled-by-env" | "vm-unavailable" };
 
 /**
  * Startup warning for the one refusal that contradicts the default-on
- * registration: every other reason honors an explicit "off" or an unfixable
- * runtime fact and stays silent.
+ * registration: every other reason honors an explicit "off" or a runtime that
+ * has a working executor anyway.
  */
 export const WORKFLOW_VM_UNAVAILABLE_WARNING =
 	"Workflow tools are unavailable this session: the isolated-vm native module failed to load. Rebuild or reinstall isolated-vm to restore the workflow tool, /workflows, and /ultraloop, or set STEP_DISABLE_WORKFLOW=1 to silence this warning.";
@@ -31,6 +31,12 @@ export const WORKFLOW_VM_UNAVAILABLE_WARNING =
  * the ultraloop opt-in. An embedder's `enabled: false` or
  * STEP_DISABLE_WORKFLOW=1 turns registration off; STEP_ENABLE_WORKFLOW is no
  * longer read.
+ *
+ * A runtime that cannot host isolated-vm is not a refusal. The V8-native addon
+ * never loads on the shipped executable's JavaScriptCore engine, so that host
+ * runs workflows through the bundled QuickJS WebAssembly executor instead (see
+ * `vm-quickjs.ts`) and registers normally. Only a V8 host whose addon failed to
+ * load is a real, fixable gap — that one warns.
  */
 export function resolveWorkflowRegistration(
 	options: { enabled?: boolean; vmExecutor?: unknown } = {},
@@ -40,9 +46,9 @@ export function resolveWorkflowRegistration(
 	if (envFlag(process.env.STEP_DISABLE_WORKFLOW)) return { enabled: false, reason: "disabled-by-env" };
 	if (options.enabled === false) return { enabled: false, reason: "not-enabled" };
 	if (!vmAvailable && !options.vmExecutor) {
-		// A missing native module is fixable on a V8 runtime (warn so the user can
-		// reinstall it); on a non-V8 runtime it never loads, so refuse silently.
-		return { enabled: false, reason: vmHostable ? "vm-unavailable" : "vm-unsupported-runtime" };
+		// Non-V8 host: QuickJS stands in for isolated-vm, so workflows are available.
+		if (!vmHostable) return { enabled: true };
+		return { enabled: false, reason: "vm-unavailable" };
 	}
 	return { enabled: true };
 }

packages/coding-agent/src/features/workflow/runtime.ts

@@ -49,14 +49,32 @@ import type {
 	WorkflowUsage,
 } from "./types.ts";
 import { emptyWorkflowUsage, mergeWorkflowUsage, workflowUsageTokens } from "./types.ts";
-import { runInIsolatedVm, type WorkflowVmHost, type WorkflowVmOptions, type WorkflowVmResult } from "./vm.ts";
+import {
+	isIsolatedVmAvailable,
+	runInIsolatedVm,
+	type WorkflowVmHost,
+	type WorkflowVmOptions,
+	type WorkflowVmResult,
+} from "./vm.ts";
+import { runInQuickJs } from "./vm-quickjs.ts";
 
 const DEFAULT_MAX_ITERATIONS = 20;
 const MAX_MAX_ITERATIONS = 100;
 const DEFAULT_STAGNATION_LIMIT = 3;
 const DEFAULT_AGENT_TIMEOUT_MS = 30 * 60 * 1_000;
 const MAX_AGENT_TIMEOUT_MS = 60 * 60 * 1_000;
 
+/**
+ * Pick the sandbox for this host. isolated-vm is a V8-native addon, so it is
+ * absent on the shipped executable's JavaScriptCore engine; QuickJS compiled to
+ * WebAssembly runs anywhere and stands in there. A V8 host with the addon
+ * installed keeps using it, so nothing changes for a source/Node run. An
+ * explicit `vmExecutor` still wins over both.
+ */
+export function defaultWorkflowVmExecutor(): NonNullable<WorkflowRuntimeOptions["vmExecutor"]> {
+	return isIsolatedVmAvailable() ? runInIsolatedVm : runInQuickJs;
+}
+
 export interface WorkflowRuntimeOptions {
 	cwd: string;
 	runId: string;
@@ -141,7 +159,7 @@ export class WorkflowRuntime {
 		this.signal = options.signal;
 		this.nestedWorkflow = options.nestedWorkflow;
 		this.now = options.now ?? Date.now;
-		this.vmExecutor = options.vmExecutor ?? runInIsolatedVm;
+		this.vmExecutor = options.vmExecutor ?? defaultWorkflowVmExecutor();
 		const startedAt = this.readNow();
 		this.startedAt = startedAt;
 		const initial: WorkflowProgress = {