diff --git a/README.md b/README.md
index 2e4c2f1..af1028c 100644
--- a/README.md
+++ b/README.md
@@ -120,6 +120,8 @@ npm run dev -- find https://objkt.com/tokens/hicetnunc/111068 --play
 npm run dev -- play "https://example.com/video.mp4" --skip-verify
 ```
 
+> **npm 12+:** `npm ci`/`npm install` fail with `Fetching packages of type "git" have been disabled` because `@feralfile/source-resolver` is a git-URL dependency and npm 12 blocks those by default. Install with `npm ci --allow-git=all` until the resolver is published to the npm registry.
+
 ## Documentation
 
 - Getting started and usage: `./docs/README.md`
diff --git a/docs/CONFIGURATION.md b/docs/CONFIGURATION.md
index 18df944..4c0876e 100644
--- a/docs/CONFIGURATION.md
+++ b/docs/CONFIGURATION.md
@@ -151,7 +151,7 @@ Setup and `device add` both preserve existing devices. Adding a device with the
 Selection rules when sending:
 
 - If you omit `-d`, the first configured device is used.
-- If you pass `-d <name>`, the CLI matches the device by `name` (exact match). If not found, you’ll see an error listing available devices.
+- If you pass `-d <name>`, the CLI matches the device by `name` (case-insensitive) or by host URL — the same rules as `device remove`/`default`/`rename`, so unnamed entries can be targeted by host. If not found, you’ll see an error listing available devices.
 
 Device cast contract:
 
diff --git a/src/commands/device.ts b/src/commands/device.ts
index e3542b3..236924a 100644
--- a/src/commands/device.ts
+++ b/src/commands/device.ts
@@ -1,7 +1,7 @@
 import { Command } from 'commander';
 import chalk from 'chalk';
 import { promises as fs } from 'fs';
-import { findExistingDeviceEntry } from '../utilities/device-lookup';
+import { findConfiguredDeviceIndex, findExistingDeviceEntry } from '../utilities/device-lookup';
 import { normalizeDeviceHost } from '../utilities/device-normalize';
 import { upsertDevice } from '../utilities/device-upsert';
 import { promoteDeviceToDefault } from '../utilities/device-default';
@@ -229,9 +229,13 @@ deviceCommand
       // existingIndex === -1 (no confirmed match, e.g. manual IP → .local migration),
       // a same-name entry is the upsertDevice case-3 migration path — blocking it would
       // prevent the user from retaining their existing device name during host migration.
+      // Case-insensitive: lookups everywhere else ignore case, so "Kitchen"
+      // alongside "kitchen" would make one of them unreachable by name.
       const nameConflict =
         existingIndex !== -1
-          ? existingDevices.find((d, i) => d.name === deviceName && i !== existingIndex)
+          ? existingDevices.find(
+              (d, i) => d.name?.toLowerCase() === deviceName.toLowerCase() && i !== existingIndex
+            )
           : undefined;
       if (nameConflict) {
         if (options.name) {
@@ -253,7 +257,9 @@ deviceCommand
         deviceName = retryAnswer || 'ff1';
         const retryConflict =
           existingIndex !== -1
-            ? existingDevices.find((d, i) => d.name === deviceName && i !== existingIndex)
+            ? existingDevices.find(
+                (d, i) => d.name?.toLowerCase() === deviceName.toLowerCase() && i !== existingIndex
+              )
             : undefined;
         if (retryConflict) {
           console.error(chalk.red(`\nName "${deviceName}" is also taken. No changes made.`));
@@ -296,23 +302,7 @@ deviceCommand
       const config = await readConfigFile(configPath);
       const existingDevices = config.ff1Devices?.devices || [];
 
-      // Match by name (case-insensitive) or by host URL so unnamed legacy/manual
-      // entries (stored without a name field) can still be targeted and removed.
-      const normalizedArg = name.toLowerCase();
-      let normalizedArgHost = '';
-      try {
-        normalizedArgHost = normalizeDeviceHost(name).toLowerCase();
-      } catch {
-        // not a valid URL — host matching will not apply
-      }
-      const deviceIndex = existingDevices.findIndex(
-        (d) =>
-          (d.name && d.name.toLowerCase() === normalizedArg) ||
-          (d.host && d.host.toLowerCase() === normalizedArg) ||
-          (normalizedArgHost &&
-            d.host &&
-            normalizeDeviceHost(d.host).toLowerCase() === normalizedArgHost)
-      );
+      const deviceIndex = findConfiguredDeviceIndex(existingDevices, name);
 
       if (deviceIndex === -1) {
         console.error(chalk.red(`\nDevice "${name}" not found`));
diff --git a/src/utilities/device-default.ts b/src/utilities/device-default.ts
index 353f7ee..500f246 100644
--- a/src/utilities/device-default.ts
+++ b/src/utilities/device-default.ts
@@ -1,4 +1,4 @@
-import { normalizeDeviceHost } from './device-normalize';
+import { findConfiguredDeviceIndex } from './device-lookup';
 import type { DeviceEntry } from './device-upsert';
 
 export interface PromoteDefaultResult {
@@ -20,22 +20,7 @@ export function promoteDeviceToDefault(
   devices: DeviceEntry[],
   identifier: string
 ): PromoteDefaultResult {
-  const normalizedArg = identifier.toLowerCase();
-  let normalizedArgHost = '';
-  try {
-    normalizedArgHost = normalizeDeviceHost(identifier).toLowerCase();
-  } catch {
-    // not a valid URL — host matching will not apply
-  }
-
-  const index = devices.findIndex(
-    (d) =>
-      (d.name && d.name.toLowerCase() === normalizedArg) ||
-      (d.host && d.host.toLowerCase() === normalizedArg) ||
-      (normalizedArgHost &&
-        d.host &&
-        normalizeDeviceHost(d.host).toLowerCase() === normalizedArgHost)
-  );
+  const index = findConfiguredDeviceIndex(devices, identifier);
 
   if (index === -1) {
     throw new Error(`Device "${identifier}" not found`);
diff --git a/src/utilities/device-lookup.ts b/src/utilities/device-lookup.ts
index 924ee29..b548f69 100644
--- a/src/utilities/device-lookup.ts
+++ b/src/utilities/device-lookup.ts
@@ -1,3 +1,5 @@
+import { normalizeDeviceHost } from './device-normalize';
+
 /**
  * Find an existing configured device that corresponds to a newly discovered host.
  *
@@ -115,3 +117,36 @@ export function findExistingDeviceEntry(
 
   return undefined;
 }
+
+/**
+ * Find the index of a configured device by a user-supplied identifier.
+ *
+ * Matches by friendly name (case-insensitive) or by host URL — raw or
+ * normalized — so unnamed legacy/manual entries (stored without a name field)
+ * can still be targeted. Shared by `device remove`, `device default`,
+ * `device rename`, and runtime `-d` resolution so every surface answers to
+ * the same identifier the same way.
+ *
+ * Returns -1 when nothing matches.
+ */
+export function findConfiguredDeviceIndex(
+  devices: Array<{ host?: string; name?: string }>,
+  identifier: string
+): number {
+  const normalizedArg = identifier.toLowerCase();
+  let normalizedArgHost = '';
+  try {
+    normalizedArgHost = normalizeDeviceHost(identifier).toLowerCase();
+  } catch {
+    // not a valid URL — host matching will not apply
+  }
+
+  return devices.findIndex(
+    (d) =>
+      (d.name && d.name.toLowerCase() === normalizedArg) ||
+      (d.host && d.host.toLowerCase() === normalizedArg) ||
+      (normalizedArgHost &&
+        d.host &&
+        normalizeDeviceHost(d.host).toLowerCase() === normalizedArgHost)
+  );
+}
diff --git a/src/utilities/device-rename.ts b/src/utilities/device-rename.ts
index fc653a9..4c6f31d 100644
--- a/src/utilities/device-rename.ts
+++ b/src/utilities/device-rename.ts
@@ -1,4 +1,4 @@
-import { normalizeDeviceHost } from './device-normalize';
+import { findConfiguredDeviceIndex } from './device-lookup';
 import type { DeviceEntry } from './device-upsert';
 
 export interface RenameDeviceResult {
@@ -33,22 +33,7 @@ export function renameDevice(
     throw new Error('New device name must not be empty');
   }
 
-  const normalizedArg = identifier.toLowerCase();
-  let normalizedArgHost = '';
-  try {
-    normalizedArgHost = normalizeDeviceHost(identifier).toLowerCase();
-  } catch {
-    // not a valid URL — host matching will not apply
-  }
-
-  const index = devices.findIndex(
-    (d) =>
-      (d.name && d.name.toLowerCase() === normalizedArg) ||
-      (d.host && d.host.toLowerCase() === normalizedArg) ||
-      (normalizedArgHost &&
-        d.host &&
-        normalizeDeviceHost(d.host).toLowerCase() === normalizedArgHost)
-  );
+  const index = findConfiguredDeviceIndex(devices, identifier);
 
   if (index === -1) {
     throw new Error(`Device "${identifier}" not found`);
diff --git a/src/utilities/ff1-compatibility.ts b/src/utilities/ff1-compatibility.ts
index cfc43b8..062c197 100644
--- a/src/utilities/ff1-compatibility.ts
+++ b/src/utilities/ff1-compatibility.ts
@@ -3,6 +3,7 @@
  */
 
 import { getFF1DeviceConfig } from '../config';
+import { findConfiguredDeviceIndex } from './device-lookup';
 import type { FF1Device, FF1DeviceConfig } from '../types';
 import * as logger from '../logger';
 
@@ -50,7 +51,8 @@ const FF1_COMMAND_POLICIES: Record<FF1Command, FF1CommandPolicy> = {
 /**
  * Load and validate the configured FF1 device selected by name.
  *
- * @param {string} [deviceName] - Optional device name, exact match required
+ * @param {string} [deviceName] - Optional device name (case-insensitive) or host URL,
+ *   resolved with the same matching rules as `device remove`/`default`/`rename`
  * @param {Object} [options] - Optional dependency overrides
  * @param {Function} [options.getFF1DeviceConfigFn] - Optional config loader override
  * @returns {FF1DeviceSelectionResult} Selected device or reason for failure
@@ -75,7 +77,8 @@ export function resolveConfiguredDevice(
   let device = deviceConfig.devices[0];
 
   if (deviceName) {
-    device = deviceConfig.devices.find((item) => item.name === deviceName) as FF1Device | undefined;
+    const index = findConfiguredDeviceIndex(deviceConfig.devices, deviceName);
+    device = index === -1 ? undefined : (deviceConfig.devices[index] as FF1Device);
     if (!device) {
       const availableNames = deviceConfig.devices
         .map((item) => item.name)
diff --git a/tests/avahi-parse.test.ts b/tests/avahi-parse.test.ts
index cc047a9..d8d7277 100644
--- a/tests/avahi-parse.test.ts
+++ b/tests/avahi-parse.test.ts
@@ -2,8 +2,8 @@
  * Regression tests for parseAvahiBrowseOutput.
  *
  * The Linux mDNS path must preserve original case and handle multi-word service
- * names. resolveConfiguredDevice() does exact-match lookups, so any case
- * mutation or truncation makes a discovered device impossible to target later.
+ * names. Lookups are case-insensitive, but stored names are display labels and
+ * round-trip into config.json — truncation or case mangling corrupts them.
  */
 import assert from 'node:assert/strict';
 import { describe, test } from 'node:test';
diff --git a/tests/device-add-conflict-cli.test.ts b/tests/device-add-conflict-cli.test.ts
new file mode 100644
index 0000000..cc9f2c9
--- /dev/null
+++ b/tests/device-add-conflict-cli.test.ts
@@ -0,0 +1,105 @@
+/**
+ * Integration test for the case-insensitive duplicate-name guard in
+ * `ff1 device add --host --name`.
+ *
+ * Lookups (`-d`, remove, default, rename) ignore case, so allowing "Kitchen"
+ * to be saved alongside "kitchen" would make one of them unreachable by name.
+ */
+import assert from 'node:assert/strict';
+import { describe, test } from 'node:test';
+import { spawnSync } from 'node:child_process';
+import { mkdtempSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join, resolve } from 'node:path';
+
+const projectRoot = resolve(__dirname, '..');
+// Spawn node directly with tsx's JS entry to avoid Windows .cmd shim
+// limitations in spawnSync (Node refuses to execute .bat/.cmd without shell).
+const tsxCli = resolve(projectRoot, 'node_modules/tsx/dist/cli.mjs');
+const cliEntry = resolve(projectRoot, 'index.ts');
+
+function makeConfig() {
+  return {
+    defaultDuration: 10,
+    ff1Devices: {
+      devices: [
+        { name: 'kitchen', host: 'http://192.168.1.10:1111' },
+        { name: 'office', host: 'http://192.168.1.11:1111' },
+      ],
+    },
+  };
+}
+
+function withTempConfig(fn: (dir: string, configPath: string) => void): void {
+  const dir = mkdtempSync(join(tmpdir(), 'ff1-device-add-conflict-'));
+  const configPath = join(dir, 'config.json');
+  writeFileSync(configPath, `${JSON.stringify(makeConfig(), null, 2)}\n`, 'utf-8');
+  try {
+    fn(dir, configPath);
+  } finally {
+    rmSync(dir, { recursive: true, force: true });
+  }
+}
+
+function runDeviceAdd(
+  cwd: string,
+  ...args: string[]
+): { status: number | null; stdout: string; stderr: string } {
+  const result = spawnSync(process.execPath, [tsxCli, cliEntry, 'device', 'add', ...args], {
+    cwd,
+    // XDG_CONFIG_HOME is redirected so the user's real ~/.config/ff1 is never touched
+    // even if cwd-based local config resolution ever changes.
+    env: { ...process.env, XDG_CONFIG_HOME: join(cwd, '.xdg') },
+    encoding: 'utf-8',
+  });
+  return {
+    status: result.status,
+    stdout: result.stdout || '',
+    stderr: result.stderr || '',
+  };
+}
+
+describe('ff1 device add — case-insensitive duplicate-name guard', () => {
+  test('rejects renaming a device to a name that differs only by case from another device', () => {
+    withTempConfig((cwd, configPath) => {
+      const originalBytes = readFileSync(configPath);
+
+      // Host matches "office", so this is an update — but "Kitchen" collides
+      // with the existing "kitchen" on the other row.
+      const { status, stderr } = runDeviceAdd(
+        cwd,
+        '--host',
+        'http://192.168.1.11:1111',
+        '--name',
+        'Kitchen'
+      );
+
+      assert.notEqual(status, 0, 'must exit non-zero on case-insensitive name conflict');
+      assert.match(stderr, /already used/i);
+
+      const afterBytes = readFileSync(configPath);
+      assert.ok(originalBytes.equals(afterBytes), 'config.json must be untouched on conflict');
+    });
+  });
+
+  test('still allows a case-only rename of the same device via add', () => {
+    withTempConfig((cwd, configPath) => {
+      const { status, stdout } = runDeviceAdd(
+        cwd,
+        '--host',
+        'http://192.168.1.11:1111',
+        '--name',
+        'Office'
+      );
+
+      assert.equal(status, 0, `expected exit 0, got ${status}: ${stdout}`);
+
+      const written = JSON.parse(readFileSync(configPath, 'utf-8'));
+      assert.deepEqual(
+        written.ff1Devices.devices.map((d: { name?: string }) => d.name),
+        ['kitchen', 'Office'],
+        'same-row case change is not a conflict'
+      );
+    });
+  });
+});
diff --git a/tests/multi-device.test.ts b/tests/multi-device.test.ts
index 611f894..ea16aec 100644
--- a/tests/multi-device.test.ts
+++ b/tests/multi-device.test.ts
@@ -63,6 +63,28 @@ describe('multi-device resolution', () => {
     assert.equal(result.device?.host, 'http://192.168.1.12:1111');
   });
 
+  test('matches device name case-insensitively', () => {
+    writeDeviceConfig([
+      { name: 'kitchen', host: 'http://192.168.1.10:1111' },
+      { name: 'office', host: 'http://192.168.1.11:1111' },
+    ]);
+
+    const result = resolveConfiguredDevice('OFFICE');
+    assert.equal(result.success, true);
+    assert.equal(result.device?.name, 'office');
+  });
+
+  test('matches by host URL so unnamed entries can be targeted with -d', () => {
+    writeDeviceConfig([
+      { name: 'kitchen', host: 'http://192.168.1.10:1111' },
+      { host: 'http://192.168.1.99:1111' },
+    ]);
+
+    const result = resolveConfiguredDevice('http://192.168.1.99:1111');
+    assert.equal(result.success, true);
+    assert.equal(result.device?.host, 'http://192.168.1.99:1111');
+  });
+
   test('returns error with available device names when requested device not found', () => {
     writeDeviceConfig([
       { name: 'kitchen', host: 'http://192.168.1.10:1111' },
@@ -89,7 +111,10 @@ describe('multi-device resolution', () => {
     assert.equal(result.device?.host, 'http://10.0.0.3:1111');
   });
 
-  test('device name matching is exact (case-sensitive)', () => {
+  test('first match wins for legacy configs with case-duplicate names', () => {
+    // device add/rename reject names that differ only by case, but configs
+    // written before that guard may still contain both. Lookups are
+    // case-insensitive, so the earlier row wins deterministically.
     writeDeviceConfig([
       { name: 'Kitchen', host: 'http://192.168.1.10:1111' },
       { name: 'kitchen', host: 'http://192.168.1.11:1111' },
@@ -97,7 +122,7 @@ describe('multi-device resolution', () => {
 
     const result = resolveConfiguredDevice('kitchen');
     assert.equal(result.success, true);
-    assert.equal(result.device?.host, 'http://192.168.1.11:1111');
+    assert.equal(result.device?.host, 'http://192.168.1.10:1111');
   });
 
   test('preserves device-specific apiKey and stable ID', () => {