fix(harness): make env.ts side-effect-free on module load for edge runtimes

Move .env file discovery and loadEnvFileCompat call out of module top level
into an exported loadDotEnvFilesIfAvailable() helper. The module now loads
cleanly in edge runtimes (Cloudflare Workers, Vercel Edge) without node:fs
access.

Node.js callers that relied on automatic .env loading must now call
loadDotEnvFilesIfAvailable() explicitly from their entry point. The
createAgentRuntime() function already does this.

Author: minpeter

packages/harness/CHANGELOG.md

@@ -1,5 +1,10 @@
 # @ai-sdk-tool/harness
 
+## 1.3.2
+
+### Fixes
+- `env.ts`: moved `.env` file discovery side-effects out of module top level into `loadDotEnvFilesIfAvailable()` helper. The module now loads safely in edge runtimes (Cloudflare Workers, Vercel Edge) without `node:fs` access. Callers that relied on the automatic `.env` loading must explicitly call `loadDotEnvFilesIfAvailable()` from their Node.js entry point.
+
 ## 1.3.1
 
 ### Patch Changes

packages/harness/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ai-sdk-tool/harness",
-  "version": "1.3.1",
+  "version": "1.3.2",
   "type": "module",
   "main": "./dist/index.js",
   "types": "./dist/index.d.ts",

packages/harness/src/env.ts

@@ -1,36 +1,42 @@
-import { existsSync } from "node:fs";
-import { dirname, resolve } from "node:path";
 import { createEnv } from "@t3-oss/env-core";
 import { z } from "zod";
 import { loadEnvFileCompat } from "./env-file";
 
-const findWorkspaceRootEnv = (startDir: string): string | null => {
-  let current = resolve(startDir);
-
-  while (true) {
-    if (existsSync(resolve(current, "pnpm-workspace.yaml"))) {
-      return resolve(current, ".env");
+/** Call this only from Node.js entry points (CLI, test harness). Safe to omit in edge runtimes. */
+export const loadDotEnvFilesIfAvailable = (): void => {
+  // eslint-disable-next-line @typescript-eslint/no-require-imports
+  const { existsSync } = require("node:fs") as typeof import("node:fs");
+  // eslint-disable-next-line @typescript-eslint/no-require-imports
+  const { dirname, resolve } = require("node:path") as typeof import("node:path");
+
+  const findWorkspaceRootEnv = (startDir: string): string | null => {
+    let current = resolve(startDir);
+
+    while (true) {
+      if (existsSync(resolve(current, "pnpm-workspace.yaml"))) {
+        return resolve(current, ".env");
+      }
+
+      const parent = dirname(current);
+      if (parent === current) {
+        return null;
+      }
+      current = parent;
     }
+  };
+
+  const envFileCandidates = [
+    resolve(process.cwd(), ".env"),
+    findWorkspaceRootEnv(process.cwd()),
+  ].filter((envPath): envPath is string => envPath !== null);
 
-    const parent = dirname(current);
-    if (parent === current) {
-      return null;
+  for (const envPath of new Set(envFileCandidates)) {
+    if (existsSync(envPath)) {
+      loadEnvFileCompat(envPath);
     }
-    current = parent;
   }
 };
 
-const ENV_FILE_CANDIDATES = [
-  resolve(process.cwd(), ".env"),
-  findWorkspaceRootEnv(process.cwd()),
-].filter((envPath): envPath is string => envPath !== null);
-
-for (const envPath of new Set(ENV_FILE_CANDIDATES)) {
-  if (existsSync(envPath)) {
-    loadEnvFileCompat(envPath);
-  }
-}
-
 export const env = createEnv({
   server: {
     /** Enable compaction debug logging to stderr. */

packages/harness/src/runtime/create-runtime.ts

@@ -1,6 +1,7 @@
 import { createAgent } from "../agent";
 import { CheckpointHistory } from "../checkpoint-history";
 import { createModelSummarizer } from "../compaction-prompts";
+import { loadDotEnvFilesIfAvailable } from "../env";
 import { SessionManager } from "../session";
 import { SkillsEngine } from "../skills";
 import type { Agent } from "../types";
@@ -42,6 +43,8 @@ export async function createAgentRuntime<
 >(
   config: AgentRuntimeConfig<TAgents, TContext>
 ): Promise<AgentRuntime<TAgents, TContext>> {
+  loadDotEnvFilesIfAvailable();
+
   const agentMap = new Map<string, DefinedAgent<TContext>>();
   for (const definition of config.agents as readonly DefinedAgent<TContext>[]) {
     if (agentMap.has(definition.name)) {