diff --git a/src/client.ts b/src/client.ts
index 03d9227..fc4a1d6 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -1361,7 +1361,7 @@ export class BetterWright {
         synced: 0,
         selected: extracted.selected,
         skipped: extracted.skipped,
-        source: extracted.source,
+        source: "path" in extracted.source ? { path: "selected" } : extracted.source,
         target: consentTarget || (this.hostTarget ? "host" : "local"),
         warnings: extracted.warnings,
       };
diff --git a/src/cookie-sync.ts b/src/cookie-sync.ts
index 37b9cab..9dfe19e 100644
--- a/src/cookie-sync.ts
+++ b/src/cookie-sync.ts
@@ -205,6 +205,9 @@ export function normalizeCookieSyncOptions(
   if (includeSessionValue !== undefined && !isBoolean(includeSessionValue)) {
     throw new TypeError("syncCookies includeSession must be a boolean.");
   }
+  if (includeSessionValue === true && "path" in source) {
+    throw new TypeError("includeSession is unavailable for explicit cookie paths.");
+  }
   const appBoundValue = untrustedField(value, "windowsAppBound");
   const windowsAppBound = appBoundValue === undefined
     ? "disabled"
diff --git a/src/daemon-client.ts b/src/daemon-client.ts
index 7d99463..25d716b 100644
--- a/src/daemon-client.ts
+++ b/src/daemon-client.ts
@@ -15,6 +15,7 @@
 import { spawn } from "node:child_process";
 import fs from "node:fs";
 import net from "node:net";
+import path from "node:path";
 import readline from "node:readline";
 
 import {
@@ -27,7 +28,7 @@ import {
 } from "./daemon.js";
 import { profileLabel, resolveProfileName } from "./profile-name.js";
 import { bunInheritedExecArgv } from "./runtime.js";
-import type { UntrustedValue } from "./untrusted-value.js";
+import { isRecord, isString, type UntrustedValue, untrustedField } from "./untrusted-value.js";
 
 const CONNECT_TIMEOUT_MS = 1_000;
 const SPAWN_WAIT_MS = 8_000;
@@ -250,6 +251,17 @@ async function waitForSocketGone(socketPath, timeoutMs = 5_000) {
  *   | {ok: false, reason: string}
  * >}
  */
+// The daemon keeps the cwd of whichever CLI spawned it, so a relative
+// cookie path must be resolved here, against the caller's directory.
+function callerRelativeCookieSource(options: UntrustedValue) {
+  const source = isRecord(options) ? untrustedField(options, "source") : undefined;
+  const sourcePath = isRecord(source) ? untrustedField(source, "path") : undefined;
+  if (!isRecord(options) || !isRecord(source) || !isString(sourcePath) || !sourcePath.trim() || path.isAbsolute(sourcePath.trim())) {
+    return options;
+  }
+  return { ...options, source: { ...source, path: path.resolve(sourcePath.trim()) } };
+}
+
 export async function connectSessionDaemon({
   home = defaultDaemonHome(),
   cliPath,
@@ -376,7 +388,7 @@ export function createDaemonBrowser(channel, { session = "default" }: any = {})
     syncCookies: (options?: any) =>
       call(
         "syncCookies",
-        [options],
+        [callerRelativeCookieSource(options)],
         Math.min(
           Math.max(Number(options?.timeoutMs) || 30_000, 1_000) + 45_000,
           180_000,
diff --git a/src/launch-config.ts b/src/launch-config.ts
index 7598faf..532061b 100644
--- a/src/launch-config.ts
+++ b/src/launch-config.ts
@@ -75,7 +75,13 @@ export function launchOptionsFromEnv(home = defaultHome(), env = process.env): L
 }
 
 export function resolveLaunchOptions(options: BetterWrightOptions): BetterWrightOptions {
-  const defaults = launchOptionsFromEnv(options.home || defaultHome());
+  // Lower-priority variables cannot reject a setting the caller supplied.
+  const env = { ...process.env };
+  if (options.headless !== undefined) delete env.BETTERWRIGHT_HEADLESS;
+  if (options.adBlock !== undefined) delete env.BETTERWRIGHT_AD_BLOCK;
+  if (options.profile !== undefined) delete env.BETTERWRIGHT_PROFILE;
+  if (options.downloadPolicy !== undefined) delete env.BETTERWRIGHT_DOWNLOAD_POLICY;
+  const defaults = launchOptionsFromEnv(options.home || defaultHome(), env);
   // A forced display mode must also cancel an inherited off-screen window.
   if (options.headless !== undefined && options.headedInvisible === undefined) defaults.headedInvisible = false;
   return { ...options, ...defaults, ...Object.fromEntries(Object.entries(options).filter(([, value]) => value !== undefined)) };
diff --git a/tests/node/client.test.ts b/tests/node/client.test.ts
index 9d38d06..c500472 100644
--- a/tests/node/client.test.ts
+++ b/tests/node/client.test.ts
@@ -373,6 +373,24 @@ test("the worker rechecks Cookie Sync consent before opening a remote CDP target
   }
 });
 
+test("an empty Cookie Sync result does not echo an explicit source path", async () => {
+  const hostTarget = {
+    connect: async () => ({ provider: { cdpUrl: "ws://127.0.0.1:9/devtools/browser/unreachable" }, close: async () => {} }),
+  };
+  const browser = new BetterWright({ hostTarget, vault: false });
+  browser._extractCookieSync = async (normalized) => ({
+    cookies: [], selected: 0, skipped: 1, warnings: [], source: { ...normalized.source },
+  });
+  try {
+    const empty = await browser.syncCookies({ source: { path: "/private/fixture/Cookies" }, domains: ["example.test"] });
+    assert.equal(empty.ok, true);
+    assert.deepEqual(empty.source, { path: "selected" });
+    assert.equal(JSON.stringify(empty).includes("/private/fixture"), false);
+  } finally {
+    await browser.close();
+  }
+});
+
 test("Cookie Sync to a host-owned target needs no cloud consent and reports the granted domains", async () => {
   const hostTarget = {
     connect: async () => ({ provider: { cdpUrl: "ws://127.0.0.1:9/devtools/browser/unreachable" }, close: async () => {} }),
diff --git a/tests/node/cookie-sync.test.ts b/tests/node/cookie-sync.test.ts
index 523fabe..c42d4b9 100644
--- a/tests/node/cookie-sync.test.ts
+++ b/tests/node/cookie-sync.test.ts
@@ -82,7 +82,10 @@ test("explicit Chromium sources read plaintext cookies outside the registry with
   }
   assert.throws(() => normalizeCookieSyncOptions({ source: { browser: "chrome", path: profile } }), /cannot be combined/);
   assert.throws(() => normalizeCookieSyncOptions({ source: { path: "\n" } }), /single-line/);
-  await assert.rejects(extractCookieSync(normalizeCookieSyncOptions({ source: { path: profile }, includeSession: true })), /includeSession/);
+  assert.throws(
+    () => normalizeCookieSyncOptions({ source: { path: profile }, includeSession: true }),
+    /includeSession is unavailable for explicit cookie paths/,
+  );
 });
 
 test("Cookie Sync normalizes source, domains, timeout, and secure defaults", () => {
diff --git a/tests/node/daemon.test.ts b/tests/node/daemon.test.ts
index 2971d57..d7c06c4 100644
--- a/tests/node/daemon.test.ts
+++ b/tests/node/daemon.test.ts
@@ -1,6 +1,7 @@
 import assert from "node:assert/strict";
 import fs from "node:fs";
 import net from "node:net";
+import path from "node:path";
 import readline from "node:readline";
 import test from "node:test";
 import {
@@ -355,6 +356,12 @@ test("Cookie Sync crosses the daemon socket as source options, not cookie plaint
     assert.equal(result.synced, 4);
     assert.deepEqual(browser.calls.at(-1), ["syncCookies", options]);
     assert.equal(JSON.stringify(browser.calls.at(-1)).includes('"cookies"'), false);
+    const relative = { source: { path: path.join("profiles", "Default") }, domains: ["example.com"] };
+    assert.equal((await proxy.syncCookies(relative)).ok, true);
+    assert.deepEqual(browser.calls.at(-1), ["syncCookies", {
+      ...relative,
+      source: { path: path.resolve("profiles", "Default") },
+    }]);
     await proxy.close();
   } finally {
     await cleanup();
diff --git a/tests/node/launch-config.test.ts b/tests/node/launch-config.test.ts
index 86509ab..e3d3e4b 100644
--- a/tests/node/launch-config.test.ts
+++ b/tests/node/launch-config.test.ts
@@ -65,6 +65,29 @@ test("environment and explicit constructor options override saved launch default
   }
 });
 
+test("invalid environment values do not reject explicitly supplied constructor options", async () => {
+  const home = makeTempDir("betterwright-launch-explicit-");
+  const invalid = { BETTERWRIGHT_HEADLESS: "maybe", BETTERWRIGHT_AD_BLOCK: "invalid",
+    BETTERWRIGHT_PROFILE: "../escape", BETTERWRIGHT_DOWNLOAD_POLICY: "sometimes" };
+  const previous = Object.fromEntries(Object.keys(invalid).map(key => [key, process.env[key]]));
+  Object.assign(process.env, invalid);
+  try {
+    const browser = new BetterWright({ home, vault: false, headless: true, adBlock: false,
+      profile: "explicit", downloadPolicy: "ask" });
+    assert.equal(browser.headless, true);
+    assert.equal(browser.adBlock, false);
+    assert.equal(browser.profile, "explicit");
+    assert.equal(browser.downloadPolicy, "ask");
+    await browser.close();
+    assert.throws(() => new BetterWright({ home, vault: false, headless: true }), /BETTERWRIGHT_AD_BLOCK/);
+  } finally {
+    for (const [key, value] of Object.entries(previous)) {
+      if (value === undefined) delete process.env[key];
+      else process.env[key] = value;
+    }
+  }
+});
+
 test("CLI daemon config includes saved identity, display and download policy in its signature", () => {
   const home = makeTempDir("betterwright-launch-daemon-");
   const file = path.join(home, "config.json");