Fixes

.gitea/workflows/ci.yml

@@ -105,6 +105,8 @@ jobs:
             exit 1
           fi
 
+          echo "Testing QVAC enable over native messaging"
+          python3 scripts/qvac-packed-selftest.py "$BIN"
           echo "PASS: smoke test complete"
 
       - name: Generate checksums

.gitea/workflows/release.yml

@@ -72,6 +72,9 @@ jobs:
             exit 1
           fi
 
+          echo "Testing QVAC enable over native messaging"
+          python3 scripts/qvac-packed-selftest.py "$BIN"
+
       - name: List release artifacts
         run: |
           echo "=== releases/ ==="

extension/dashboard.js

@@ -280,7 +280,7 @@ function renderCapabilitiesPage(state) {
         <div class="health-row"><span class="k">Available</span><span class="v">${q.available ? 'yes' : 'no'}</span></div>
         <div class="health-row"><span class="k">Device</span><span class="v">${escapeHtml(q.device || '—')}</span></div>
         <div class="health-row"><span class="k">Backend</span><span class="v">${escapeHtml(q.backend || q.backendId || '—')}</span></div>
-        <div class="health-row"><span class="k">GPU</span><span class="v">${escapeHtml(q.deviceName || '—')}</span></div>
+        <div class="health-row"><span class="k">GPU</span><span class="v">${escapeHtml(q.deviceName || (q.vram ? String(q.vram) : '—'))}</span></div>
         <div class="health-row"><span class="k">Model</span><span class="v">${escapeHtml(q.friendlyId || q.modelId || 'none')}</span></div>
         <div class="health-row"><span class="k">Plugins</span><span class="v">${escapeHtml((q.plugins || []).join(', ') || '—')}</span></div>
         <div class="health-row"><span class="k">OpenAI</span><span class="v">${escapeHtml(q.openaiUrl || 'off')}</span></div>

native-host/index.mjs

@@ -33,6 +33,7 @@ import {
 } from './register-default-packs.mjs';
 import _messenger from './messenger.js';
 import _host from './host.js';
+import selftest from './qvac/selftest.js';
 
 installConsoleToStderr();
 normalizeBareVersions();
@@ -49,6 +50,8 @@ if (process.argv.includes('--extract-addons')) {
     await warmDefaultModules();
     await extractAddons(DEFAULT_ADDON_PACKAGES);
   })();
+} else if (process.argv.includes('--qvac-selftest') || process.env.BRIDGE_SWARM_QVAC_SELFTEST === '1') {
+  selftest.runQvacSelftest(logErr, normalizeBareVersions);
 } else {
   try {
     startHost(_messenger, _host);

native-host/qvac/device.js

@@ -44,7 +44,7 @@ function backendLabel(resources) {
   if (process.platform === 'darwin' || drivers.metal) {
     return { backend: 'metal', backendId: 1, deviceName: gpuName, vram };
   }
-  if (drivers.vulkan || process.platform === 'linux' || process.platform === 'win32') {
+  if (drivers.vulkan || hasGpu(resources)) {
     return { backend: 'vulkan', backendId: 3, deviceName: gpuName, vram };
   }
   return { backend: 'cpu', backendId: 0, deviceName: gpuName, vram };

native-host/qvac/engine.js

@@ -12,6 +12,7 @@ const { ensureQvacRoot } = require('../capabilities/paths.js');
 const catalog = require('./catalog.js');
 const device = require('./device.js');
 const events = require('./events.js');
+const llamacppHost = require('./llamacpp-host.js');
 
 const SKIP = process.env.BRIDGE_SWARM_SKIP_QVAC === '1';
 
@@ -68,7 +69,10 @@ function setUserEnabled(on) {
   if (userEnabled === next) return;
   userEnabled = next;
   initPromise = null;
-  if (!next) initError = 'disabled';
+  if (!next) {
+    initError = 'disabled';
+    lastResources = null;
+  }
 }
 
 function disabledError() {
@@ -108,6 +112,11 @@ async function assembleSdk() {
     return null;
   }
   normalizeBareVersions();
+  try {
+    llamacppHost.patchLlamaInterface(log);
+  } catch (err) {
+    log('llm backends patch skipped: ' + ((err && err.message) || err));
+  }
   ensureQvacRoot();
   if (!process.env.QVAC_CONFIG_PATH) {
     const cfg = path.join(__dirname, '..', 'qvac.config.json');
@@ -120,14 +129,24 @@ async function assembleSdk() {
     await import('@qvac/fabric');
   } catch (_) {}
 
-  const infMain = await tryImport('@qvac/inference/plugins');
+  let infMain;
+  try {
+    infMain = await import('@qvac/inference/plugins');
+  } catch (err) {
+    infMain = { __error: err };
+  }
   if (infMain.__error) {
     initError = infMain.__error.message || String(infMain.__error);
     log('inference plugins unavailable: ' + initError);
     return null;
   }
 
-  const llmMod = await tryImport('@qvac/inference/llamacpp-completion/plugin');
+  let llmMod;
+  try {
+    llmMod = await import('@qvac/inference/llamacpp-completion/plugin');
+  } catch (err) {
+    llmMod = { __error: err };
+  }
   if (llmMod.__error) {
     initError = llmMod.__error.message || String(llmMod.__error);
     log('llm plugin unavailable: ' + initError);
@@ -182,9 +201,14 @@ function ensureInit() {
   if (initPromise) return initPromise;
   normalizeBareVersions();
   initPromise = assembleSdk()
-    .then((s) => {
+    .then(async (s) => {
       sdk = s;
       if (!s) initPromise = null;
+      else {
+        try {
+          await probeHardware(s);
+        } catch (_) {}
+      }
       return s;
     })
     .catch((err) => {
@@ -195,6 +219,8 @@ function ensureInit() {
 }
 
 function publicStatus() {
+  const hw = lastResources || {};
+  const modelLoaded = !!loaded.modelId;
   return {
     enabled: isUserEnabled(),
     available: isUserEnabled() && !!sdk && !skipped(),
@@ -206,11 +232,11 @@ function publicStatus() {
     constant: loaded.constant,
     modelType: loaded.modelType,
     tools: loaded.tools,
-    device: loaded.device,
-    backend: loaded.backend,
-    backendId: loaded.backendId,
-    deviceName: loaded.deviceName,
-    vram: loaded.vram,
+    device: modelLoaded ? loaded.device : hw.deviceDefault || loaded.device,
+    backend: loaded.backend || hw.backend || null,
+    backendId: loaded.backendId != null ? loaded.backendId : hw.backendId,
+    deviceName: loaded.deviceName || hw.deviceName || null,
+    vram: loaded.vram || hw.vram || null,
     ctxSize: loaded.ctxSize,
     platform: process.platform,
     arch: process.arch,
@@ -230,8 +256,13 @@ const pickDevice = device.pickDevice;
 const backendLabel = device.backendLabel;
 
 async function probeGpuInfo() {
-  const gpuMod = await tryImport('bare-gpu-info');
-  if (gpuMod.__error) return null;
+  let gpuMod;
+  try {
+    gpuMod = await import('bare-gpu-info');
+  } catch (err) {
+    log('bare-gpu-info unavailable: ' + ((err && err.message) || err));
+    return null;
+  }
   try {
     const GPUInfo = gpuMod.default || gpuMod.GPUInfo || gpuMod;
     if (typeof GPUInfo !== 'function') return null;
@@ -243,19 +274,18 @@ async function probeGpuInfo() {
       if (typeof info.destroy === 'function') info.destroy();
     } catch (_) {}
     return { gpus, drivers, length };
-  } catch (_) {
+  } catch (err) {
+    log('gpu probe failed: ' + ((err && err.message) || err));
     return null;
   }
 }
 
-async function resources(opts) {
-  if (!isUserEnabled()) throw disabledError();
-  const s = await ensureInit();
+async function probeHardware(s) {
   const ram = totalmem();
   let qvacRes = null;
   if (s && typeof s.getSystemResources === 'function') {
     try {
-      qvacRes = await s.getSystemResources({ sample: !!(opts && opts.sample) });
+      qvacRes = await s.getSystemResources({ sample: false });
     } catch (err) {
       qvacRes = { error: err.message };
     }
@@ -265,6 +295,7 @@ async function resources(opts) {
   if (gpuProbe && gpuProbe.gpus && gpuProbe.gpus[0] && gpuProbe.gpus[0].memory) {
     merged.vram = gpuProbe.gpus[0].memory;
   }
+  const bl = backendLabel(merged);
   lastResources = {
     totalRamBytes: ram,
     capabilities: qvacRes && qvacRes.capabilities,
@@ -274,11 +305,31 @@ async function resources(opts) {
     drivers: gpuProbe && gpuProbe.drivers,
     suggest: catalog.suggestProfile({ totalRamBytes: ram, vramBytes: merged.vram }),
     deviceDefault: pickDevice('auto', merged).device,
-    ...backendLabel(merged),
+    ...bl,
   };
+  log(
+    'hardware ' +
+      lastResources.deviceDefault +
+      '/' +
+      (lastResources.backend || 'none') +
+      (lastResources.deviceName ? ' ' + lastResources.deviceName : '')
+  );
   return lastResources;
 }
 
+async function resources(opts) {
+  if (!isUserEnabled()) throw disabledError();
+  const s = await ensureInit();
+  if (opts && opts.sample && s && typeof s.getSystemResources === 'function') {
+    try {
+      const qvacRes = await s.getSystemResources({ sample: true });
+      if (lastResources) lastResources.sample = qvacRes && qvacRes.sample;
+    } catch (_) {}
+  }
+  if (lastResources && !opts) return lastResources;
+  return probeHardware(s);
+}
+
 async function resolveSrc(s, modelSrc) {
   if (modelSrc && typeof modelSrc === 'object') return modelSrc;
   const constant = catalog.resolveModelConstant(modelSrc);
@@ -307,7 +358,7 @@ async function load(opts, onProgress) {
   const entry = catalog.findCatalogEntry(opts.model || opts.modelSrc || opts.friendlyId);
   const modelSrc = await resolveSrc(s, opts.modelSrc || (entry && entry.constant) || opts.model);
   const res = lastResources || (await resources({ sample: false }));
-  const dev = pickDevice(opts.device || 'auto', res);
+  let dev = pickDevice(opts.device || 'auto', res);
   const tools = opts.tools !== false && (!entry || entry.tools !== false);
   const ctxSize = opts.ctxSize || opts.ctx_size || (entry && entry.ctxSize) || 8192;
   const modelConfig = Object.assign(
@@ -339,8 +390,42 @@ async function load(opts, onProgress) {
   }
   if (opts.delegate) loadOpts.delegate = opts.delegate;
 
-  const modelId = await s.loadModel(loadOpts);
-  const bl = backendLabel(res);
+  log(
+    'load ' +
+      ((entry && entry.id) || opts.model || 'model') +
+      ' device=' +
+      modelConfig.device +
+      ' ngl=' +
+      modelConfig.gpu_layers +
+      ' ctx=' +
+      modelConfig.ctx_size
+  );
+
+  let modelId;
+  try {
+    modelId = await s.loadModel(loadOpts);
+  } catch (err) {
+    const msg = llamacppHost.flattenError(err);
+    log('load failed: ' + msg);
+    const requested = String(opts.device || 'auto').toLowerCase();
+    if (dev.device === 'gpu' && requested !== 'cpu') {
+      log('retrying load on cpu');
+      modelConfig.device = 'cpu';
+      modelConfig.gpu_layers = 0;
+      try {
+        modelId = await s.loadModel(loadOpts);
+        dev = { device: 'cpu', gpu_layers: 0, fallback: 'cpu' };
+      } catch (err2) {
+        throw new Error(llamacppHost.flattenError(err2));
+      }
+    } else {
+      throw new Error(msg);
+    }
+  }
+  const bl =
+    dev.device === 'cpu'
+      ? Object.assign({}, backendLabel(res), { backend: 'cpu', backendId: 0 })
+      : backendLabel(res);
   loaded = {
     modelId,
     friendlyId: (entry && entry.id) || opts.model || null,
@@ -549,6 +634,7 @@ async function close() {
   }
   sdk = null;
   initPromise = null;
+  lastResources = null;
 }
 
 function setIdleUnloadMin(min) {

native-host/qvac/llamacpp-host.js

@@ -0,0 +1,122 @@
+/**
+ * Packed Bare extracts the llama addon .bare + backend .so files under /tmp,
+ * but addon.js still sets backendsDir from bundled __dirname (`bare:/...`).
+ * C++ cannot dlopen that URL; llama.cpp then runs --fit against a broken
+ * backend path and init fails with "Failed to initialize model".
+ *
+ * Point backendsDir at the extracted prebuilds directory before createInstance.
+ */
+
+function posixDirname(p) {
+  const n = String(p || '').replace(/\\/g, '/').replace(/\/+$/, '');
+  const i = n.lastIndexOf('/');
+  if (i < 0) return n;
+  if (i === 0) return '/';
+  return n.slice(0, i);
+}
+
+function flattenError(err) {
+  const parts = [];
+  let cur = err;
+  for (let n = 0; cur && n < 6; n++) {
+    const msg = cur && cur.message ? String(cur.message) : cur ? String(cur) : '';
+    if (msg && parts.indexOf(msg) === -1) parts.push(msg);
+    cur = cur && cur.cause;
+  }
+  return parts.join(' | ') || 'unknown error';
+}
+
+function hrefOf(url) {
+  if (!url) return '';
+  if (typeof url === 'string') return url;
+  if (typeof url.href === 'string') return url.href;
+  try {
+    return String(url);
+  } catch (_) {
+    return '';
+  }
+}
+
+function fileUrlToPath(href) {
+  if (!href || href.indexOf('file:') !== 0) return null;
+  try {
+    const url = require('bare-url');
+    if (url && typeof url.fileURLToPath === 'function') return url.fileURLToPath(href);
+  } catch (_) {}
+  let rest = href.replace(/^file:\/\//, '');
+  if (/^\/[A-Za-z]:\//.test(rest)) rest = rest.slice(1);
+  try {
+    rest = decodeURIComponent(rest);
+  } catch (_) {}
+  return rest;
+}
+
+/**
+ * addon.js uses path.join(packageRoot, 'prebuilds').
+ * Extracted .bare lives at prebuilds/<host>/qvac__llm-llamacpp.bare
+ */
+function backendsDirFromAddonHref(href) {
+  const raw = hrefOf(href);
+  if (!raw || !/qvac__llm-llamacpp|llm-llamacpp/i.test(raw)) return null;
+  const file = raw.indexOf('file:') === 0 ? fileUrlToPath(raw) : raw.indexOf('bare:') === 0 ? null : raw;
+  if (!file) return null;
+  const base = file.replace(/\\/g, '/');
+  if (!/\.(bare|node)$/i.test(base)) return null;
+  return posixDirname(posixDirname(file));
+}
+
+function resolveBackendsDir() {
+  try {
+    const cache = typeof Bare !== 'undefined' && Bare.Addon && Bare.Addon.cache;
+    if (cache) {
+      const hrefs = Object.keys(cache);
+      for (let i = 0; i < hrefs.length; i++) {
+        const dir = backendsDirFromAddonHref(hrefs[i]);
+        if (dir) return dir;
+        const addon = cache[hrefs[i]];
+        const fromUrl = backendsDirFromAddonHref(addon && addon.url);
+        if (fromUrl) return fromUrl;
+      }
+    }
+  } catch (_) {}
+  return null;
+}
+
+function patchLlamaInterface(logFn) {
+  const log = typeof logFn === 'function' ? logFn : function () {};
+  let addon;
+  try {
+    addon = require('@qvac/llm-llamacpp/addon.js');
+  } catch (err) {
+    log('llm addon.js unavailable: ' + ((err && err.message) || err));
+    return false;
+  }
+  const Orig = addon && addon.LlamaInterface;
+  if (!Orig) return false;
+  if (Orig.__bsBackendsPatched) return true;
+  function Wrapped(binding, configurationParams, outputCb) {
+    if (!configurationParams) configurationParams = {};
+    if (!configurationParams.config) configurationParams.config = {};
+    const dir = resolveBackendsDir();
+    if (dir) {
+      configurationParams.config.backendsDir = dir;
+      log('llm backendsDir ' + dir);
+    }
+    return new Orig(binding, configurationParams, outputCb);
+  }
+  Wrapped.prototype = Orig.prototype;
+  try {
+    Object.setPrototypeOf(Wrapped, Orig);
+  } catch (_) {}
+  Wrapped.__bsBackendsPatched = true;
+  Orig.__bsBackendsPatched = true;
+  addon.LlamaInterface = Wrapped;
+  return true;
+}
+
+module.exports = {
+  flattenError,
+  backendsDirFromAddonHref,
+  resolveBackendsDir,
+  patchLlamaInterface,
+};

native-host/qvac/selftest.js

@@ -0,0 +1,21 @@
+function runQvacSelftest(logErr, normalizeBareVersions) {
+  logErr('qvac-selftest starting');
+  try {
+    normalizeBareVersions();
+  } catch (err) {
+    logErr('qvac-selftest normalize fail: ' + ((err && err.message) || err));
+  }
+  logErr('qvac-selftest importing plugins');
+  import('@qvac/inference/plugins')
+    .then((mod) => {
+      logErr('qvac-selftest ok plugins=' + typeof (mod.plugins || mod.default));
+      process.exit(0);
+    })
+    .catch((err) => {
+      const msg = String((err && err.message) || err);
+      logErr('qvac-selftest fail: ' + msg);
+      process.exit(/INVALID_VERSION/i.test(msg) ? 1 : 0);
+    });
+}
+
+module.exports = { runQvacSelftest };

native-host/qvac/semver-patch.js

@@ -15,13 +15,6 @@ function concreteVersion(input) {
   return m ? m[1] : input;
 }
 
-function coerceEnginesMap(engines) {
-  if (!engines || typeof engines !== 'object') return engines;
-  const out = {};
-  for (const key of Object.keys(engines)) out[key] = concreteVersion(engines[key]);
-  return out;
-}
-
 function log(msg) {
   try {
     process.stderr.write('[bridge-swarm-qvac] ' + msg + '\n');
@@ -70,24 +63,6 @@ function normalizeBareVersions() {
   } catch (_) {}
 }
 
-function patchBareModule() {
-  try {
-    const Module = typeof module !== 'undefined' && module.constructor;
-    if (!Module) return;
-    const wrap = (name) => {
-      const orig = Module[name];
-      if (typeof orig !== 'function' || orig.__bsPatched) return;
-      Module[name] = function patchedModuleFn() {
-        normalizeBareVersions();
-        return orig.apply(this, arguments);
-      };
-      Module[name].__bsPatched = true;
-    };
-    wrap('resolve');
-    wrap('asset');
-  } catch (_) {}
-}
-
 function install() {
   try {
     const semver = require('bare-semver');
@@ -103,17 +78,16 @@ function install() {
   try {
     const resolve = require('bare-module-resolve');
     if (typeof resolve.validateEngines === 'function' && !resolve.validateEngines.__bsPatched) {
-      const orig = resolve.validateEngines;
-      resolve.validateEngines = function patchedValidateEngines(packageURL, packageEngines, opts) {
-        const next = Object.assign({}, opts || {});
-        if (next.engines) next.engines = coerceEnginesMap(next.engines);
-        return orig(packageURL, packageEngines, next);
+      resolve.validateEngines = function patchedValidateEngines() {
+        // Packed Bare.versions.bare can be a range; skip engines checks.
+        return;
       };
       resolve.validateEngines.__bsPatched = true;
     }
   } catch (_) {}
 
-  patchBareModule();
+  // Do not wrap Module.resolve: the packed runtime's resolver is inside
+  // bare:/bare.bundle and wrapping module.constructor.resolve can stall imports.
   normalizeBareVersions();
 }
 

native-host/register-default-packs.mjs

@@ -87,6 +87,15 @@ export async function warmDefaultModules() {
   try {
     await import('@qvac/inference');
   } catch (_) {}
+  try {
+    await import('@qvac/inference/plugins');
+  } catch (_) {}
+  try {
+    await import('@qvac/inference/llamacpp-completion/plugin');
+  } catch (_) {}
+  try {
+    await import('@qvac/inference/models');
+  } catch (_) {}
   try {
     await import('bare-gpu-info');
   } catch (_) {}

native-host/test-bare.js

@@ -154,7 +154,6 @@ async function testBareVersionsCoerce() {
 
     const { satisfies } = require('bare-semver');
     ok(satisfies('^1.30.3', '^1.30.3') === true, 'satisfies coerces caret runtime version');
-    ok(!!(module.constructor.resolve && module.constructor.resolve.__bsPatched), 'runtime Module.resolve wrapped');
 
     Object.defineProperty(Bare, 'versions', {
       configurable: true,

scripts/build-distributable.js

@@ -164,6 +164,7 @@ function patchBundle(bundle) {
   }
 
   let jsonFixed = 0;
+  let enginesStripped = 0;
   let keysToProcess = typeof bundle.keys === 'function' ? [...bundle.keys()] : Object.keys(bundle.files || {});
   for (const key of keysToProcess) {
     if (!key.endsWith('.json')) continue;
@@ -195,6 +196,18 @@ function patchBundle(bundle) {
       }
     }
     if (content && content.length > 0) {
+      const keyNormSlash = key.replace(/\\/g, '/');
+      if (/package\.json$/i.test(keyNormSlash)) {
+        try {
+          const json = JSON.parse(content.toString());
+          if (json && json.engines) {
+            delete json.engines;
+            content = Buffer.from(JSON.stringify(json));
+            bundle.write(key, content);
+            enginesStripped++;
+          }
+        } catch (_) {}
+      }
       const keyNoLead = key.replace(/^\/+/, '');
       const prefixSlash = 'runtime.bundle/' + keyNoLead;
       const prefixLead = '/runtime.bundle/' + keyNoLead;
@@ -207,6 +220,11 @@ function patchBundle(bundle) {
   void resolveKey;
 
   if (jsonFixed > 0) console.log(`  Patched ${jsonFixed} empty/invalid .json entries`);
+  if (enginesStripped > 0) {
+    console.log(
+      `  Stripped engines from ${enginesStripped} package.json files (packed Bare.versions.bare can be a range)`
+    );
+  }
   console.log('  Added runtime.bundle pathname variants for .json entries');
 }
 

scripts/qvac-packed-selftest.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+"""Send qvac.setEnabled over native messaging and fail on INVALID_VERSION."""
+import json
+import os
+import struct
+import subprocess
+import sys
+import threading
+import time
+
+
+def main():
+    binpath = sys.argv[1]
+    env = os.environ.copy()
+    env.setdefault('BRIDGE_SWARM_STORAGE', '/tmp/bs-qvac-packed-selftest')
+    proc = subprocess.Popen(
+        [binpath],
+        stdin=subprocess.PIPE,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        env=env,
+    )
+    err_chunks = []
+
+    def pump_err():
+        while True:
+            line = proc.stderr.readline()
+            if not line:
+                break
+            err_chunks.append(line)
+            sys.stderr.buffer.write(line)
+            sys.stderr.flush()
+
+    threading.Thread(target=pump_err, daemon=True).start()
+    time.sleep(1.5)
+    msg = json.dumps(
+        {
+            'id': 1,
+            'type': 'capability',
+            'payload': {
+                'pack': 'qvac',
+                'cmd': 'setEnabled',
+                'payload': {'enabled': True},
+            },
+        }
+    ).encode()
+    proc.stdin.write(struct.pack('<I', len(msg)) + msg)
+    proc.stdin.flush()
+    hdr = proc.stdout.read(4)
+    if len(hdr) < 4:
+        print('FAIL: no native-messaging reply', file=sys.stderr)
+        proc.kill()
+        return 1
+    n = struct.unpack('<I', hdr)[0]
+    body = proc.stdout.read(n).decode('utf-8', 'replace')
+    print('REPLY', body[:4000])
+    time.sleep(0.5)
+    proc.kill()
+    blob = body + b''.join(err_chunks).decode('utf-8', 'replace')
+    if 'INVALID_VERSION' in blob:
+        print('FAIL: packed host still throws INVALID_VERSION', file=sys.stderr)
+        return 1
+    print('PASS: no INVALID_VERSION')
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())

scripts/test-host-units.js

@@ -182,10 +182,32 @@ function testDeviceFallback() {
   assert.strictEqual(gpuMissing.fallback, 'cpu');
   const metal = device.backendLabel({ drivers: { metal: true }, gpus: [{ name: 'Apple M4', memory: 1 }] });
   assert.strictEqual(metal.backend, 'metal');
+  const vulkan = device.backendLabel({ drivers: { vulkan: true }, gpus: [{ name: 'NVIDIA' }] });
+  assert.strictEqual(vulkan.backend, 'vulkan');
+  assert.strictEqual(vulkan.deviceName, 'NVIDIA');
+  const cpuOnly = device.backendLabel({ drivers: {}, gpus: [] });
+  assert.strictEqual(cpuOnly.backend, 'cpu');
 }
 
 testDeviceFallback();
 
+function testLlamacppHostHelpers() {
+  const host = require('../native-host/qvac/llamacpp-host.js');
+  assert.strictEqual(
+    host.backendsDirFromAddonHref(
+      'file:///tmp/bridge-swarm-host-abc/node_modules/@qvac/llm-llamacpp/prebuilds/linux-x64/qvac__llm-llamacpp.bare'
+    ),
+    '/tmp/bridge-swarm-host-abc/node_modules/@qvac/llm-llamacpp/prebuilds'
+  );
+  assert.strictEqual(host.backendsDirFromAddonHref('bare:/app.bundle/node_modules/@qvac/llm-llamacpp/addon.js'), null);
+  const wrapped = new Error('Failed to load model: Failed to initialize model');
+  wrapped.cause = new Error('failed to load model');
+  assert.ok(host.flattenError(wrapped).indexOf('Failed to initialize model') !== -1);
+  assert.ok(host.flattenError(wrapped).indexOf('failed to load model') !== -1);
+}
+
+testLlamacppHostHelpers();
+
 function testCompletionEventMap() {
   const events = require('../native-host/qvac/events.js');
   assert.deepStrictEqual(events.normalizeCompletionEvent({ type: 'contentDelta', text: 'hi' }), {