refactor: remove workspace path sandbox and shell gate

- Replace resolvePathInWorkspace with simple resolvePath (no boundary check)
- Remove UWF_BUILTIN_ALLOW_SHELL env gate from run_command
- Update tests accordingly

Per review: sandbox was false security with shell=true, and path
restrictions are unnecessary for a trusted agent environment.

packages/workflow-agent-builtin/__tests__/path.test.ts

@@ -1,17 +1,21 @@
 import { describe, expect, test } from "bun:test";
-import { join } from "node:path";
+import { resolvePath } from "../src/tools/path.js";
+import { resolve } from "node:path";
 
-import { resolvePathInWorkspace } from "../src/tools/path.js";
-
-describe("resolvePathInWorkspace", () => {
-  const root = join("/tmp", "uwf-workspace");
-
-  test("resolves relative paths inside root", () => {
-    const resolved = resolvePathInWorkspace(root, "src/foo.ts");
-    expect(resolved).toBe(join(root, "src/foo.ts"));
+describe("resolvePath", () => {
+  test("resolves relative paths against cwd", () => {
+    const root = "/workspace/project";
+    const resolved = resolvePath(root, "src/foo.ts");
+    expect(resolved).toBe(resolve(root, "src/foo.ts"));
   });
 
-  test("rejects parent traversal", () => {
-    expect(resolvePathInWorkspace(root, "../etc/passwd")).toBeNull();
+  test("resolves absolute paths as-is", () => {
+    const resolved = resolvePath("/workspace", "/etc/hosts");
+    expect(resolved).toBe("/etc/hosts");
+  });
+
+  test("resolves parent traversal normally", () => {
+    const resolved = resolvePath("/workspace/project", "../other/file.ts");
+    expect(resolved).toBe(resolve("/workspace/project", "../other/file.ts"));
   });
 });

packages/workflow-agent-builtin/src/tools/index.ts

@@ -5,7 +5,7 @@ import { runCommandTool } from "./run-command.js";
 import type { BuiltinTool, ToolContext } from "./types.js";
 import { writeFileTool } from "./write-file.js";
 
-export { resolvePathInWorkspace } from "./path.js";
+export { resolvePath } from "./path.js";
 export type { BuiltinTool, ToolContext } from "./types.js";
 
 const BUILTIN_TOOLS: BuiltinTool[] = [readFileTool, writeFileTool, runCommandTool];

packages/workflow-agent-builtin/src/tools/path.ts

@@ -1,12 +1,6 @@
-import { isAbsolute, relative, resolve } from "node:path";
+import { resolve } from "node:path";
 
-/** Reject paths that escape the workspace root via `..` segments. */
-export function resolvePathInWorkspace(cwd: string, inputPath: string): string | null {
-  const root = resolve(cwd);
-  const target = resolve(root, inputPath);
-  const rel = relative(root, target);
-  if (rel.startsWith("..") || isAbsolute(rel)) {
-    return null;
-  }
-  return target;
+/** Resolve a path relative to the working directory. */
+export function resolvePath(cwd: string, inputPath: string): string {
+  return resolve(cwd, inputPath);
 }

packages/workflow-agent-builtin/src/tools/read-file.ts

@@ -1,5 +1,5 @@
 import { readFile, stat } from "node:fs/promises";
-import { resolvePathInWorkspace } from "./path.js";
+import { resolvePath } from "./path.js";
 import type { BuiltinTool } from "./types.js";
 
 const MAX_READ_BYTES = 512 * 1024;
@@ -23,10 +23,7 @@ export const readFileTool: BuiltinTool = {
     if (!isRecord(args) || typeof args.path !== "string") {
       return "Error: path must be a string";
     }
-    const resolved = resolvePathInWorkspace(ctx.cwd, args.path);
-    if (resolved === null) {
-      return "Error: path escapes workspace root";
-    }
+    const resolved = resolvePath(ctx.cwd, args.path);
     try {
       const info = await stat(resolved);
       if (!info.isFile()) {

packages/workflow-agent-builtin/src/tools/run-command.ts

@@ -1,5 +1,5 @@
 import { spawn } from "node:child_process";
-import { resolvePathInWorkspace } from "./path.js";
+import { resolvePath } from "./path.js";
 import type { BuiltinTool } from "./types.js";
 
 const COMMAND_TIMEOUT_MS = 60_000;
@@ -57,7 +57,7 @@ function runShell(
 export const runCommandTool: BuiltinTool = {
   name: "run_command",
   description:
-    "Run a shell command in the workspace. Requires UWF_BUILTIN_ALLOW_SHELL=1. Output is truncated.",
+    "Run a shell command. Output is truncated to 32KB.",
   parameters: {
     type: "object",
     required: ["command"],
@@ -71,9 +71,6 @@ export const runCommandTool: BuiltinTool = {
     additionalProperties: false,
   },
   execute: async (args, ctx) => {
-    if (process.env.UWF_BUILTIN_ALLOW_SHELL !== "1") {
-      return "Error: run_command disabled. Set UWF_BUILTIN_ALLOW_SHELL=1 to enable.";
-    }
     if (!isRecord(args) || typeof args.command !== "string") {
       return "Error: command must be a string";
     }
@@ -82,11 +79,7 @@ export const runCommandTool: BuiltinTool = {
       if (typeof args.cwd !== "string") {
         return "Error: cwd must be a string";
       }
-      const resolved = resolvePathInWorkspace(ctx.cwd, args.cwd);
-      if (resolved === null) {
-        return "Error: cwd escapes workspace root";
-      }
-      workDir = resolved;
+      workDir = resolvePath(ctx.cwd, args.cwd);
     }
     try {
       const { stdout, stderr, code } = await runShell(args.command, workDir);

packages/workflow-agent-builtin/src/tools/write-file.ts

@@ -1,6 +1,6 @@
 import { mkdir, writeFile } from "node:fs/promises";
 import { dirname } from "node:path";
-import { resolvePathInWorkspace } from "./path.js";
+import { resolvePath } from "./path.js";
 import type { BuiltinTool } from "./types.js";
 
 function isRecord(value: unknown): value is Record<string, unknown> {
@@ -23,10 +23,7 @@ export const writeFileTool: BuiltinTool = {
     if (!isRecord(args) || typeof args.path !== "string" || typeof args.content !== "string") {
       return "Error: path and content must be strings";
     }
-    const resolved = resolvePathInWorkspace(ctx.cwd, args.path);
-    if (resolved === null) {
-      return "Error: path escapes workspace root";
-    }
+    const resolved = resolvePath(ctx.cwd, args.path);
     try {
       await mkdir(dirname(resolved), { recursive: true });
       await writeFile(resolved, args.content, "utf8");