diff --git a/proxy.js b/proxy.js
index 19972ec..6d4ac6e 100644
--- a/proxy.js
+++ b/proxy.js
@@ -196,7 +196,7 @@ async function getContent(httpModule, origReq, origRes) {
   let isHit = '';
 
   const requestDetails = {
-    host: mappedUrl.host || origUrl.host,
+    host: mappedUrl.hostname || origUrl.hostname || mappedUrl.host || origUrl.host,
     port: mappedUrl.port || origUrl.port,
     path: mappedUrl.path || origUrl.path,
     username: origUrl.username,
diff --git a/test/proxy.test.js b/test/proxy.test.js
index f0be4ee..aa23d92 100644
--- a/test/proxy.test.js
+++ b/test/proxy.test.js
@@ -4,7 +4,15 @@ process.env.PROXY_KUTTI_CONFIG = '/nonexistent/proxy-kutti-test-config';
 const os = require('os');
 const fs = require('fs');
 const path = require('path');
+const http = require('http');
+const net = require('net');
+const { spawn } = require('child_process');
 const tmpCacheDir = fs.mkdtempSync(path.join(os.tmpdir(), 'proxy-kutti-test-'));
+const proxyScriptPath = path.resolve(__dirname, '../proxy.js');
+const PROXY_STARTUP_TIMEOUT_MS = 5000;
+const PROXY_REQUEST_TIMEOUT_MS = 3000;
+const PROXY_SHUTDOWN_TIMEOUT_MS = 1000;
+const PROXY_INTEGRATION_TEST_TIMEOUT_MS = 15000;
 process.env.PROXY_KUTTI_cache_dir = tmpCacheDir;
 
 const { describe, it, after } = require('node:test');
@@ -26,6 +34,25 @@ const {
 after(() => fs.rmSync(tmpCacheDir, { recursive: true, force: true }));
 
 const hoursAgo = hours => new Date(Date.now() - hours * 60 * 60 * 1000).toISOString();
+const wait = ms => new Promise(resolve => setTimeout(resolve, ms));
+const waitFor = async (predicate, timeoutMs = 1000, intervalMs = 10) => {
+  const deadline = Date.now() + timeoutMs;
+  while (Date.now() < deadline) {
+    if (predicate()) return;
+    await wait(intervalMs);
+  }
+  throw new Error(`Timed out after ${timeoutMs}ms`);
+};
+
+const getFreePort = () =>
+  new Promise((resolve, reject) => {
+    const server = net.createServer();
+    server.listen(0, '127.0.0.1', () => {
+      const { port } = server.address();
+      server.close(() => resolve(port));
+    });
+    server.on('error', reject);
+  });
 
 describe('parseUrlMappings', () => {
   it('parses a sed-style pattern into search regex and replacement', () => {
@@ -175,6 +202,96 @@ describe('addHoursToDate', () => {
   });
 });
 
+describe('cacheHit', () => {
+  it('returns null for stale entries that match cache_control', async () => {
+    const cachedFile = path.join(tmpCacheDir, 'stale-hit.data');
+    const cachedFileMeta = `${cachedFile}.meta`;
+    fs.writeFileSync(cachedFile, 'stale-content');
+    fs.writeFileSync(
+      cachedFileMeta,
+      JSON.stringify({
+        headers: { 'content-type': 'text/plain' },
+        statusCode: 200,
+        'proxy-kutti-orig-request': { 'cache-date': hoursAgo(25) },
+      })
+    );
+
+    const result = await cacheHit({
+      host: 'registry.npmjs.org',
+      path: '/lodash',
+      method: 'GET',
+      headers: {},
+      state: { cachedFile, cachedFileMeta },
+    });
+    assert.strictEqual(result, null);
+  });
+
+  it('returns an empty body stream for HEAD cache hits', async () => {
+    const cachedFile = path.join(tmpCacheDir, 'head-hit.data');
+    const cachedFileMeta = `${cachedFile}.meta`;
+    fs.writeFileSync(cachedFile, 'should-not-be-read-for-head');
+    fs.writeFileSync(
+      cachedFileMeta,
+      JSON.stringify({
+        headers: { 'content-type': 'application/octet-stream' },
+        statusCode: 204,
+        'proxy-kutti-orig-request': { 'cache-date': hoursAgo(1) },
+      })
+    );
+
+    const proxyRes = await cacheHit({
+      host: 'example.com',
+      path: '/head',
+      method: 'HEAD',
+      headers: {},
+      state: { cachedFile, cachedFileMeta },
+    });
+    assert.notStrictEqual(proxyRes, null);
+    assert.strictEqual(proxyRes.statusCode, 204);
+    let body = '';
+    for await (const chunk of proxyRes) body += chunk;
+    assert.strictEqual(body, '');
+  });
+
+  it('backfills missing proxy-kutti-orig-request in legacy metadata', async () => {
+    const cachedFile = path.join(tmpCacheDir, 'legacy-hit.data');
+    const cachedFileMeta = `${cachedFile}.meta`;
+    fs.writeFileSync(cachedFile, 'legacy-body');
+    fs.writeFileSync(
+      cachedFileMeta,
+      JSON.stringify({
+        headers: { 'content-type': 'text/plain' },
+        statusCode: 200,
+      })
+    );
+
+    const requestDetails = {
+      host: 'legacy.example.com',
+      path: '/legacy-hit',
+      method: 'GET',
+      headers: {},
+      state: { cachedFile, cachedFileMeta },
+    };
+    const proxyRes = await cacheHit(requestDetails);
+    assert.notStrictEqual(proxyRes, null);
+
+    await waitFor(() => {
+      try {
+        const updatedMeta = JSON.parse(fs.readFileSync(cachedFileMeta, 'utf8'));
+        return Boolean(updatedMeta['proxy-kutti-orig-request']);
+      } catch {
+        return false;
+      }
+    });
+
+    const updatedMeta = JSON.parse(fs.readFileSync(cachedFileMeta, 'utf8'));
+    assert.ok(updatedMeta['proxy-kutti-orig-request']);
+    assert.strictEqual(updatedMeta['proxy-kutti-orig-request'].host, requestDetails.host);
+    assert.strictEqual(updatedMeta['proxy-kutti-orig-request'].state, null);
+    assert.ok(updatedMeta['proxy-kutti-orig-request']['cache-date']);
+  });
+});
+
 describe('guessContentType', () => {
   it('maps known extensions case-insensitively', () => {
     assert.strictEqual(guessContentType('foo-1.2.3.zip'), 'application/zip');
@@ -242,4 +359,143 @@ describe('importIntoCache', () => {
     const metaData = JSON.parse(fs.readFileSync(`${cachedFile}.meta`, 'utf8'));
     assert.strictEqual(metaData.headers['content-type'], 'application/x-mystery');
   });
+
+  it('supports --content-type=<mime-type> syntax', async () => {
+    const srcFile = path.join(tmpCacheDir, 'src-asset-equals.bin');
+    fs.writeFileSync(srcFile, 'binary stuff');
+
+    const importUrl = 'https://example.com/downloads/asset-equals.bin';
+    await importIntoCache([importUrl, srcFile, '--content-type=application/x-equals']);
+
+    const { cachedFile } = computeCacheDetails('https', 'GET', importUrl);
+    const metaData = JSON.parse(fs.readFileSync(`${cachedFile}.meta`, 'utf8'));
+    assert.strictEqual(metaData.headers['content-type'], 'application/x-equals');
+  });
+
+  it('supports --content-type before positional args', async () => {
+    const srcFile = path.join(tmpCacheDir, 'src-asset-leading-flag.tgz');
+    fs.writeFileSync(srcFile, 'binary stuff');
+
+    const importUrl = 'https://example.com/downloads/asset-leading-flag.tgz';
+    await importIntoCache(['--content-type', 'application/custom-tgz', importUrl, srcFile]);
+
+    const { cachedFile } = computeCacheDetails('https', 'GET', importUrl);
+    const metaData = JSON.parse(fs.readFileSync(`${cachedFile}.meta`, 'utf8'));
+    assert.strictEqual(metaData.headers['content-type'], 'application/custom-tgz');
+  });
+
+  it('falls back to inferred content type when --content-type has no value', async () => {
+    const srcFile = path.join(tmpCacheDir, 'src-asset-missing-override.tgz');
+    fs.writeFileSync(srcFile, 'binary stuff');
+
+    const importUrl = 'https://example.com/downloads/asset-missing-override.tgz';
+    await importIntoCache([importUrl, srcFile, '--content-type']);
+
+    const { cachedFile } = computeCacheDetails('https', 'GET', importUrl);
+    const metaData = JSON.parse(fs.readFileSync(`${cachedFile}.meta`, 'utf8'));
+    assert.strictEqual(metaData.headers['content-type'], 'application/gzip');
+  });
+});
+
+describe('proxy integration cache behavior', () => {
+  it(
+    'serves identical second request from cache without hitting origin again',
+    { timeout: PROXY_INTEGRATION_TEST_TIMEOUT_MS },
+    async () => {
+    const e2eCacheDir = fs.mkdtempSync(path.join(os.tmpdir(), 'proxy-kutti-e2e-'));
+    const originPort = await getFreePort();
+    const proxyPort = await getFreePort();
+    let originRequestCount = 0;
+    const originServer = http.createServer((req, res) => {
+      originRequestCount++;
+      const body = JSON.stringify({ requestCount: originRequestCount, path: req.url });
+      res.writeHead(200, {
+        'content-type': 'application/json',
+        'content-length': Buffer.byteLength(body),
+      });
+      res.end(body);
+    });
+    await new Promise(resolve => originServer.listen(originPort, '127.0.0.1', resolve));
+
+    const proxyProcess = spawn('node', [proxyScriptPath], {
+      cwd: path.dirname(proxyScriptPath),
+      env: {
+        ...process.env,
+        PROXY_KUTTI_CONFIG: '/nonexistent/proxy-kutti-e2e-config',
+        PROXY_KUTTI_host: '127.0.0.1',
+        PROXY_KUTTI_port: String(proxyPort),
+        PROXY_KUTTI_cache_dir: e2eCacheDir,
+      },
+      stdio: ['ignore', 'pipe', 'pipe'],
+    });
+
+    const waitForProxyReady = new Promise((resolve, reject) => {
+      const timeout = setTimeout(() => reject(new Error('Timed out waiting for proxy to start')), PROXY_STARTUP_TIMEOUT_MS);
+      proxyProcess.stdout.on('data', data => {
+        if (data.toString().includes('Proxy-kutti is running')) {
+          clearTimeout(timeout);
+          resolve();
+        }
+      });
+      proxyProcess.on('exit', code => {
+        clearTimeout(timeout);
+        reject(new Error(`Proxy exited early with code ${code}`));
+        }
+      );
+    });
+
+    const requestViaProxy = pathName =>
+      new Promise((resolve, reject) => {
+        const req = http.request(
+          {
+            hostname: '127.0.0.1',
+            port: proxyPort,
+            method: 'GET',
+            path: `http://127.0.0.1:${originPort}${pathName}`,
+          },
+          res => {
+            let body = '';
+            res.on('data', chunk => (body += chunk));
+            res.on('end', () => resolve({ statusCode: res.statusCode, body }));
+          }
+        );
+        req.setTimeout(PROXY_REQUEST_TIMEOUT_MS, () => req.destroy(new Error('Timed out waiting for proxy response')));
+        req.on('error', reject);
+        req.end();
+      });
+
+    try {
+      await waitForProxyReady;
+      const first = await requestViaProxy('/api/e2e-cache-hit');
+      const countAfterFirst = originRequestCount;
+      const second = await requestViaProxy('/api/e2e-cache-hit');
+
+      assert.strictEqual(first.statusCode, 200);
+      assert.strictEqual(second.statusCode, 200);
+      assert.strictEqual(originRequestCount, countAfterFirst);
+      assert.strictEqual(
+        JSON.parse(first.body).requestCount,
+        JSON.parse(second.body).requestCount
+      );
+
+      const cachedFile = `${e2eCacheDir}/http/127.0.0.1:${originPort}/GET/api/e2e-cache-hit.data`;
+      assert.ok(fs.existsSync(cachedFile));
+      assert.ok(fs.existsSync(`${cachedFile}.meta`));
+    } finally {
+      await new Promise(resolve => originServer.close(resolve));
+      const proxyExit = new Promise(resolve => proxyProcess.once('exit', resolve));
+      if (proxyProcess.exitCode === null) {
+        proxyProcess.kill('SIGTERM');
+      }
+      const exitedAfterTerm = await Promise.race([
+        proxyExit.then(() => true),
+        wait(PROXY_SHUTDOWN_TIMEOUT_MS).then(() => false),
+      ]);
+      if (!exitedAfterTerm && proxyProcess.exitCode === null) {
+        proxyProcess.kill('SIGKILL');
+        await proxyExit;
+      }
+      fs.rmSync(e2eCacheDir, { recursive: true, force: true });
+    }
+  });
 });