diff --git a/docs/development-workflow.md b/docs/development-workflow.md
index b3ec30cfc..824375074 100644
--- a/docs/development-workflow.md
+++ b/docs/development-workflow.md
@@ -58,24 +58,27 @@ changes can wait for one planned release.
 
 Run from the intended worktree:
 
-- `pnpm dev`: real app; uses the existing `Guild Wars` profile by default.
+- `pnpm dev`: builds and verifies the real launcher; uses the existing `Guild Wars` profile by default.
 - `pnpm dev:signed`: signed Dev package with persistent login; requires Apple signing configuration.
 - `pnpm launcher:fixture fresh`: disposable offline launcher, not a playable client.
 - `pnpm tools:dev`: standalone browser UI, not the application.
 
-For isolated real-app checks, build successfully, then launch with an explicit
-application path and disposable profile:
+For isolated real-app checks:
 
 ```bash
-pnpm build &&
-  dev_profile=$(mktemp -d "${TMPDIR:-/tmp}/gwonmac-dev.XXXXXX") &&
-  test -n "$dev_profile" &&
-  GW_BACKGROUND_LAUNCH=0 GW_EXPECT_USER_DATA="$dev_profile" \
-    pnpm exec electron "$PWD" --user-data-dir="$dev_profile"
+pnpm dev --isolated
 ```
 
-Reuse that profile during the task. It may download game data; saved login is
-memory-only. Do not copy player data without authorization.
+The command owns the app path and profile assertion. It prints `launcher-open`
+only after verifying the actual process, checkout, profile and visible
+`gw://app/launcher/index.html`. A welcome page, identity mismatch or startup
+failure cannot produce that receipt. Launcher verification does not mean that
+the game cache is ready or gameplay passed.
+
+Keep the command running. After closing the app, reuse its printed profile with
+`pnpm dev --profile /absolute/profile/path`. An already-running profile refuses
+before building; preserve that session. The profile may download game data;
+saved login is memory-only. Do not copy player data without authorization.
 
 `GW_EXPECT_USER_DATA` checks the actual profile before client preparation.
 Aliases such as `/var` and `/private/var` resolve to the same existing directory;
@@ -83,8 +86,9 @@ an empty, missing, dangling, or different expected path refuses preparation.
 Do not remove this assertion to work around a profile mismatch.
 
 For a cached-only check, first provision the authorized game artifacts and
-chunks in that profile, then add `GW_REQUIRE_CACHED_CLIENT=1` to the launch.
-Use `pnpm certification doctor --profile "$dev_profile"` to inspect readiness.
+chunks in that profile, then use `pnpm dev --profile /absolute/profile/path --cached-only`.
+Use `pnpm certification doctor --profile /absolute/profile/path` with that same
+printed profile to inspect readiness.
 Cache provisioning does not require copying account settings or credentials.
 Keep logs, screenshots, and the profile path in ignored `test-results/`, outside
 `build/`: the build command deletes that directory. Do not redirect into the
@@ -92,9 +96,11 @@ same file that a command is reading to recover its profile path.
 Playwright suites own only `test-results/electron/` and `test-results/tools-e2e/`.
 Keep development evidence and profiles outside those disposable suite directories.
 
-Use `cua.getState()` for discovery. Confirm the process working directory and
-profile, then attach through its debugger or exact running app path. App lookup
-can launch bare Electron if the process is absent; its welcome page is not gwonmac.
+For UI attachment, first confirm that the receipt's PID is still running with
+the printed checkout and profile. Then use `cua.getState()` for discovery and
+select the exact running app path. `cua.getApp()` starts an absent app: never
+use it to launch or check whether Electron is running. If the process exited,
+repeat the development command and wait for a new receipt before attaching.
 
 Verify `gw://app/launcher/index.html` before handoff. Starting the game hides the
 launcher; restore it with **Window → Show Launcher**. Do not click Play merely
diff --git a/package.json b/package.json
index b22e9ea5b..39b667328 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,7 @@
   "scripts": {
     "postinstall": "install-electron",
     "build": "node scripts/build.mjs",
-    "dev": "pnpm build && electron-forge start",
+    "dev": "node --import ./scripts/ts-hook.mjs scripts/run-dev.ts",
     "dev:signed": "node --import ./scripts/ts-hook.mjs scripts/run-signed-dev.ts",
     "launcher:fixture": "pnpm build && node --import ./scripts/ts-hook.mjs scripts/launcher-fixture.ts",
     "test:signed-dev": "node --import ./scripts/ts-hook.mjs scripts/run-signed-dev.ts --test-keychain",
diff --git a/scripts/run-dev.ts b/scripts/run-dev.ts
new file mode 100644
index 000000000..362ce0dbc
--- /dev/null
+++ b/scripts/run-dev.ts
@@ -0,0 +1,121 @@
+/** Launch the intended checkout and prove its launcher identity before handoff. */
+import { spawnSync } from "node:child_process";
+import { mkdir, mkdtemp, realpath } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+import type { ElectronApplication } from "playwright";
+import { defaultGuildWarsProfile } from "../src/tools/enhancement-workspace.js";
+import { activeProfileOwner } from "./enhancements-live/profile-lock.js";
+
+const root = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
+const launcherUrl = "gw://app/launcher/index.html";
+
+export async function verifyDevelopmentApp(app: ElectronApplication, expectedRoot: string, expectedProfile: string) {
+  const identity = await app.evaluate(({ app }) => ({
+    root: app.getAppPath(), profile: app.getPath("userData"), pid: process.pid,
+  }));
+  if (await realpath(identity.root) !== await realpath(expectedRoot)
+    || await realpath(identity.profile) !== await realpath(expectedProfile)) {
+    throw new Error("Development app identity mismatch; no launcher handoff.");
+  }
+  const page = await app.firstWindow({ timeout: 30_000 });
+  await page.waitForURL(launcherUrl, { timeout: 30_000 });
+  await page.waitForLoadState("domcontentloaded");
+  const visible = await app.evaluate(({ BrowserWindow }, url) => {
+    const window = BrowserWindow.getAllWindows().find((candidate) => candidate.webContents.getURL() === url);
+    if (!window) return false;
+    if (window.isVisible()) return true;
+    // DOM readiness can precede the native ready-to-show event. Observe the
+    // actual show event instead of declaring success early or racing a snapshot.
+    return new Promise<boolean>((resolve) => {
+      const shown = () => { clearTimeout(timeout); resolve(true); };
+      const timeout = setTimeout(() => {
+        window.removeListener("show", shown);
+        resolve(false);
+      }, 10_000);
+      window.once("show", shown);
+    });
+  }, launcherUrl);
+  if (!visible) throw new Error("Development launcher is not visible; no launcher handoff.");
+  return { ...identity, url: launcherUrl, status: "launcher-open" as const };
+}
+
+export async function launchDevelopmentApp(userData: string, cachedOnly: boolean) {
+  const profile = await realpath(userData);
+  const owner = await activeProfileOwner(profile);
+  if (owner !== null) {
+    throw new Error(`Profile already running (PID ${owner}); preserve that session instead of opening another app.`);
+  }
+  const env: Record<string, string> = {};
+  for (const [key, value] of Object.entries(process.env)) {
+    if (value !== undefined) env[key] = value;
+  }
+  delete env.ELECTRON_RUN_AS_NODE;
+  Object.assign(env, {
+    GW_BACKGROUND_LAUNCH: "0", GW_EXPECT_USER_DATA: profile,
+    GW_REQUIRE_CACHED_CLIENT: cachedOnly ? "1" : "0",
+  });
+  const { _electron: electron } = await import("playwright");
+  const app = await electron.launch({
+    cwd: root, args: [root, `--user-data-dir=${profile}`], env,
+    timeout: 30_000,
+  });
+  try {
+    const receipt = await verifyDevelopmentApp(app, root, profile);
+    return { app, receipt };
+  } catch (error) {
+    await app.close();
+    throw error;
+  }
+}
+
+async function main() {
+  const args = process.argv.slice(2).filter((arg) => arg !== "--");
+  const usage = "usage: pnpm dev [--isolated | --profile PATH] [--cached-only]";
+  if (args.length === 1 && args[0] === "--help") { console.log(usage); return; }
+  let profileInput: string | undefined;
+  let isolated = false;
+  let cachedOnly = process.env.GW_REQUIRE_CACHED_CLIENT === "1";
+  for (let i = 0; i < args.length; i += 1) {
+    const arg = args[i];
+    if (arg === "--isolated" && !isolated && profileInput === undefined) isolated = true;
+    else if (arg === "--profile" && !isolated && profileInput === undefined) {
+      const value = args[++i];
+      if (!value || value.startsWith("--")) throw new Error(usage);
+      profileInput = value;
+    } else if (arg === "--cached-only") cachedOnly = true;
+    else throw new Error(usage);
+  }
+  // Reject bad or active explicit profiles before paying for a build. Recheck
+  // ownership during launch because another process may start while building.
+  let profile = profileInput === undefined ? undefined : await realpath(profileInput);
+  if (!isolated) {
+    profile ??= defaultGuildWarsProfile();
+    const owner = await activeProfileOwner(profile);
+    if (owner !== null) throw new Error(`Profile already running (PID ${owner}); preserve that session.`);
+  }
+  const build = spawnSync(process.execPath, ["scripts/build.mjs"], {
+    cwd: root, stdio: "inherit",
+  });
+  if (build.error || build.status !== 0) throw new Error("Development build failed; app was not launched.");
+  profile ??= await mkdtemp(path.join(tmpdir(), "gwonmac-dev-"));
+  await mkdir(profile, { recursive: true });
+  const { app, receipt } = await launchDevelopmentApp(profile, cachedOnly);
+  // These are local developer coordinates, never production diagnostics.
+  console.log(JSON.stringify(receipt));
+  console.log("Launcher verified. Keep this command running. Reuse the printed profile on the next launch.");
+  const close = () => { void app.close(); };
+  process.once("SIGINT", close);
+  process.once("SIGTERM", close);
+  await app.waitForEvent("close", { timeout: 0 });
+  process.removeListener("SIGINT", close);
+  process.removeListener("SIGTERM", close);
+}
+
+if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
+  main().catch((error: unknown) => {
+    console.error(error instanceof Error ? error.message : "Development launch failed.");
+    process.exitCode = 1;
+  });
+}
diff --git a/tests/electron/development-launch.spec.ts b/tests/electron/development-launch.spec.ts
new file mode 100644
index 000000000..cbc88ac3d
--- /dev/null
+++ b/tests/electron/development-launch.spec.ts
@@ -0,0 +1,33 @@
+import assert from "node:assert/strict";
+import { mkdtemp, realpath, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { _electron as electron, test } from "@playwright/test";
+import { launchDevelopmentApp, verifyDevelopmentApp } from "../../scripts/run-dev.js";
+import { root } from "./fixtures.mjs";
+
+test("development launch proves the real visible launcher and refuses a second profile owner", async () => {
+  const profile = await mkdtemp(path.join(tmpdir(), "gwonmac-dev-proof-"));
+  try {
+    const { app, receipt } = await launchDevelopmentApp(profile, true);
+    try {
+      assert.equal(receipt.root, root);
+      assert.equal(receipt.profile, await realpath(profile));
+      assert.equal(receipt.pid, app.process().pid);
+      assert.equal(receipt.url, "gw://app/launcher/index.html");
+      assert.equal(receipt.status, "launcher-open");
+      await assert.rejects(launchDevelopmentApp(profile, true), /Profile already running/);
+      assert.equal(app.process().exitCode, null, "refusal preserves the original app");
+    } finally { await app.close(); }
+  } finally { await rm(profile, { recursive: true, force: true }); }
+});
+
+test("bare Electron cannot be reported as the project launcher", async () => {
+  const profile = await mkdtemp(path.join(tmpdir(), "gwonmac-bare-electron-"));
+  try {
+    const app = await electron.launch({ args: [`--user-data-dir=${profile}`] });
+    try {
+      await assert.rejects(verifyDevelopmentApp(app, root, profile), /identity mismatch/);
+    } finally { await app.close(); }
+  } finally { await rm(profile, { recursive: true, force: true }); }
+});
diff --git a/tests/unit/feature-discovery.test.ts b/tests/unit/feature-discovery.test.ts
index 713306ec4..459e28ca9 100644
--- a/tests/unit/feature-discovery.test.ts
+++ b/tests/unit/feature-discovery.test.ts
@@ -141,3 +141,22 @@ test("live execution retains opt-in and cannot launch after a failed build", ()
   assert.equal(failed.status, 9, failed.stderr);
   assert.match(failed.stderr, /build failed/);
 });
+
+test("development launch rejects ambiguous profiles before build or Electron import", () => {
+  assert.equal(run("scripts/run-dev.ts", ["--help"]).status, 0);
+  for (const args of [["--profile"], ["--profile", ""], ["--isolated", "--profile", "/tmp"], ["--unknown"]]) {
+    const result = run("scripts/run-dev.ts", args);
+    assert.equal(result.status, 1);
+    assert.match(result.stderr, /usage:/);
+  }
+  const missing = run("scripts/run-dev.ts", ["--profile", path.join(temporary, "absent")]);
+  assert.equal(missing.status, 1);
+  assert.match(missing.stderr, /ENOENT/);
+});
+
+test("development launch cannot import Electron or report success after a failed build", () => {
+  const result = run("scripts/run-dev.ts", ["--isolated"], { DISCOVERY_TEST_BUILD_FAILURE: "1" });
+  assert.equal(result.status, 1);
+  assert.match(result.stderr, /build failed/);
+  assert.doesNotMatch(result.stdout, /launcher-open/);
+});