diff --git a/server/config.js b/server/config.js
index a1a9e54..0e232c0 100644
--- a/server/config.js
+++ b/server/config.js
@@ -1,7 +1,5 @@
 'use strict';
 
-const path = require('path');
-const fs = require('fs');
 const { createStorage } = require('./storage');
 const { resolveLogsDir } = require('./paths');
 
@@ -188,7 +186,6 @@ function joinUpstreamPath(upstream, requestUrl) {
   return basePath + (urlPath.startsWith('/') ? urlPath : `/${urlPath}`);
 }
 const LOGS_DIR = resolveLogsDir();
-const LEGACY_LOGS_DIR = path.join(__dirname, '..', 'logs');
 const RESTORE_DAYS = parseInt(process.env.RESTORE_DAYS || '3', 10);
 const LOG_RETENTION_DAYS = parseInt(process.env.LOG_RETENTION_DAYS || '14', 10);
 // 0 = only session-start anchor; N>0 = force full snapshot every N delta writes
@@ -279,23 +276,11 @@ function inferMaxContext(model, system, usage) {
   return base;
 }
 
-// Ensure logs dir exists; migrate from legacy location if needed
-if (!fs.existsSync(LOGS_DIR)) {
-  fs.mkdirSync(LOGS_DIR, { recursive: true });
-  // One-time migration from old package-relative logs/
-  const legacyIndex = path.join(LEGACY_LOGS_DIR, 'index.ndjson');
-  if (fs.existsSync(legacyIndex)) {
-    try {
-      const files = fs.readdirSync(LEGACY_LOGS_DIR);
-      for (const f of files) {
-        fs.renameSync(path.join(LEGACY_LOGS_DIR, f), path.join(LOGS_DIR, f));
-      }
-      console.log(`Migrated logs from ${LEGACY_LOGS_DIR} → ${LOGS_DIR}`);
-    } catch (e) {
-      console.error(`Log migration failed: ${e.message}`);
-    }
-  }
-}
+// Logs-dir creation and the one-time legacy-logs migration now live in the
+// local storage adapter's init() (server/storage/local.js), invoked once at
+// startup via `await config.storage.init()`. config.js performs no filesystem
+// side effects at require time, and the migration only runs for the local
+// backend (S3/R2 never reads LOGS_DIR).
 
 module.exports = {
   PORT,
diff --git a/server/storage/index.js b/server/storage/index.js
index fa16539..ef8958b 100644
--- a/server/storage/index.js
+++ b/server/storage/index.js
@@ -1,7 +1,14 @@
 'use strict';
 
+const path = require('path');
 const { createLocalStorage } = require('./local');
 
+// Old package-relative logs/ location (<repo>/logs). The local adapter migrates
+// from here into the resolved logs dir on first init(). Resolved here — at the
+// single point where the local adapter is constructed — so it never runs at
+// config-import time and never applies to non-local backends (e.g. S3/R2).
+const LEGACY_LOGS_DIR = path.join(__dirname, '..', '..', 'logs');
+
 // Wraps a storage adapter so every async write is tracked in an in-flight Set.
 // drain() awaits all pending writes — used on shutdown so process.exit doesn't
 // kill the event loop while fs.writeFile is mid-flight, leaving 0-byte files.
@@ -54,7 +61,7 @@ function createStorage() {
     case 'local':
     default: {
       const { resolveLogsDir } = require('../paths');
-      adapter = createLocalStorage(resolveLogsDir());
+      adapter = createLocalStorage(resolveLogsDir(), { legacyDir: LEGACY_LOGS_DIR });
       break;
     }
   }
diff --git a/server/storage/local.js b/server/storage/local.js
index 4e9fbc7..e52c9f4 100644
--- a/server/storage/local.js
+++ b/server/storage/local.js
@@ -7,11 +7,34 @@ const path = require('path');
 /**
  * Local filesystem storage adapter.
  * @param {string} logsDir — absolute path to the logs directory
+ * @param {object} [opts]
+ * @param {string} [opts.legacyDir] — absolute path to a pre-existing
+ *   package-relative logs/ directory to migrate from on first init(). When
+ *   omitted, no legacy migration is attempted. This logic lives only on the
+ *   local adapter, so non-local backends (e.g. S3) never touch the local FS.
  * @returns {import('./interface').StorageAdapter}
  */
-function createLocalStorage(logsDir) {
+function createLocalStorage(logsDir, opts = {}) {
   const sharedDir = path.join(logsDir, 'shared');
   const indexPath = path.join(logsDir, 'index.ndjson');
+  const legacyDir = opts.legacyDir || null;
+
+  // One-time, best-effort migration from the old package-relative logs/
+  // location. Errors are logged and swallowed — a failed migration must never
+  // crash startup (mirrors the original catch-and-log behavior).
+  async function migrateLegacyLogs() {
+    if (!legacyDir) return;
+    const legacyIndex = path.join(legacyDir, 'index.ndjson');
+    if (!fs.existsSync(legacyIndex)) return;
+    try {
+      for (const f of await fsp.readdir(legacyDir)) {
+        await fsp.rename(path.join(legacyDir, f), path.join(logsDir, f));
+      }
+      console.log(`Migrated logs from ${legacyDir} → ${logsDir}`);
+    } catch (e) {
+      console.error(`Log migration failed: ${e.message}`);
+    }
+  }
 
   return {
     supportsDelta: true,
@@ -20,8 +43,13 @@ function createLocalStorage(logsDir) {
     location: logsDir,
 
     async init() {
+      // Snapshot before mkdir so we migrate only into a freshly-created logs
+      // dir — mirrors the original `if (!fs.existsSync(LOGS_DIR))` guard and
+      // never clobbers a populated logs dir.
+      const logsDirExisted = fs.existsSync(logsDir);
       await fsp.mkdir(logsDir, { recursive: true });
       await fsp.mkdir(sharedDir, { recursive: true });
+      if (!logsDirExisted) await migrateLegacyLogs();
     },
 
     async write(id, suffix, data) {
diff --git a/test/legacy-migration.test.js b/test/legacy-migration.test.js
new file mode 100644
index 0000000..30e5368
--- /dev/null
+++ b/test/legacy-migration.test.js
@@ -0,0 +1,150 @@
+'use strict';
+
+// Covers the legacy-logs migration after it was folded into the local storage
+// adapter's init() (it previously ran as a require-time side effect in
+// config.js — fired on every import, ignored STORAGE_BACKEND). Properties:
+//   1. local init() migrates a fresh logs dir from the legacy dir;
+//   2. no legacy index.ndjson → no migration;
+//   3. a pre-existing logs dir blocks migration (never clobbers);
+//   4. no legacyDir wired (the S3/non-local path) → no local migration;
+//   5. migration is best-effort — a rename error is swallowed, init() resolves;
+//   6. requiring config.js has NO migration side effect at import time.
+// All filesystem work is isolated to per-test temp dirs; the real ~/.ccxray is
+// never touched.
+
+const { describe, it } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('fs');
+const path = require('path');
+const os = require('os');
+const { spawn } = require('child_process');
+
+const { createLocalStorage } = require('../server/storage/local');
+
+function mkroot(label) {
+  return fs.mkdtempSync(path.join(os.tmpdir(), `ccxray-legmig-${label}-`));
+}
+
+describe('legacy-logs migration (local storage adapter init)', () => {
+  it('migrates legacy files into a freshly-created logs dir', async () => {
+    const root = mkroot('mig');
+    const logsDir = path.join(root, 'logs');
+    const legacyDir = path.join(root, 'pkglogs');
+    fs.mkdirSync(legacyDir, { recursive: true });
+    fs.writeFileSync(path.join(legacyDir, 'index.ndjson'), '{"id":"old"}\n');
+    fs.writeFileSync(path.join(legacyDir, '2026-01-01_req.json'), '{"model":"x"}');
+    try {
+      await createLocalStorage(logsDir, { legacyDir }).init();
+      assert.equal(fs.readFileSync(path.join(logsDir, 'index.ndjson'), 'utf8'), '{"id":"old"}\n');
+      assert.ok(fs.existsSync(path.join(logsDir, '2026-01-01_req.json')), 'payload file migrated');
+      assert.deepEqual(fs.readdirSync(legacyDir), [], 'legacy dir emptied');
+      assert.ok(fs.existsSync(path.join(logsDir, 'shared')), 'shared/ still created by init');
+    } finally {
+      fs.rmSync(root, { recursive: true, force: true });
+    }
+  });
+
+  it('does NOT migrate when the legacy dir has no index.ndjson', async () => {
+    const root = mkroot('noidx');
+    const logsDir = path.join(root, 'logs');
+    const legacyDir = path.join(root, 'pkglogs');
+    fs.mkdirSync(legacyDir, { recursive: true });
+    fs.writeFileSync(path.join(legacyDir, 'stray.json'), 'orphan');
+    try {
+      await createLocalStorage(logsDir, { legacyDir }).init();
+      assert.ok(!fs.existsSync(path.join(logsDir, 'stray.json')), 'no migration without index.ndjson sentinel');
+      assert.ok(fs.existsSync(path.join(legacyDir, 'stray.json')), 'stray file left in place');
+    } finally {
+      fs.rmSync(root, { recursive: true, force: true });
+    }
+  });
+
+  it('does NOT migrate when the logs dir already existed (no clobber)', async () => {
+    const root = mkroot('exist');
+    const logsDir = path.join(root, 'logs');
+    const legacyDir = path.join(root, 'pkglogs');
+    fs.mkdirSync(logsDir, { recursive: true });
+    fs.mkdirSync(legacyDir, { recursive: true });
+    fs.writeFileSync(path.join(legacyDir, 'index.ndjson'), '{"id":"old"}\n');
+    try {
+      await createLocalStorage(logsDir, { legacyDir }).init();
+      assert.ok(!fs.existsSync(path.join(logsDir, 'index.ndjson')), 'pre-existing logs dir must block migration');
+      assert.ok(fs.existsSync(path.join(legacyDir, 'index.ndjson')), 'legacy file stays put');
+    } finally {
+      fs.rmSync(root, { recursive: true, force: true });
+    }
+  });
+
+  it('does NOT migrate when no legacyDir is wired (the S3 / non-local path)', async () => {
+    const root = mkroot('nolegacy');
+    const logsDir = path.join(root, 'logs');
+    const legacyDir = path.join(root, 'pkglogs');
+    fs.mkdirSync(legacyDir, { recursive: true });
+    fs.writeFileSync(path.join(legacyDir, 'index.ndjson'), '{"id":"old"}\n');
+    try {
+      // No opts → no legacyDir. This is exactly how non-local backends are
+      // wired: only the local branch in storage/index.js passes legacyDir.
+      await createLocalStorage(logsDir).init();
+      assert.ok(!fs.existsSync(path.join(logsDir, 'index.ndjson')), 'no legacyDir → no migration');
+      assert.ok(fs.existsSync(path.join(legacyDir, 'index.ndjson')), 'legacy untouched');
+      assert.ok(fs.existsSync(logsDir), 'logs dir still created by init');
+    } finally {
+      fs.rmSync(root, { recursive: true, force: true });
+    }
+  });
+
+  it('is best-effort: a rename error is swallowed and init() still resolves', async () => {
+    const root = mkroot('err');
+    const logsDir = path.join(root, 'logs');
+    const legacyDir = path.join(root, 'pkglogs');
+    fs.mkdirSync(legacyDir, { recursive: true });
+    fs.writeFileSync(path.join(legacyDir, 'index.ndjson'), '{"id":"old"}\n');
+    // A legacy file named 'shared' collides with the shared/ directory that
+    // init() creates → fsp.rename(file → existing dir) fails. The migration
+    // must catch-and-log, not reject init().
+    fs.writeFileSync(path.join(legacyDir, 'shared'), 'collide');
+    try {
+      await assert.doesNotReject(
+        () => createLocalStorage(logsDir, { legacyDir }).init(),
+        'a failed rename must not crash init()',
+      );
+      assert.ok(
+        fs.existsSync(path.join(logsDir, 'shared')) && fs.statSync(path.join(logsDir, 'shared')).isDirectory(),
+        'shared/ dir remains intact after the failed migration',
+      );
+    } finally {
+      fs.rmSync(root, { recursive: true, force: true });
+    }
+  });
+});
+
+describe('config.js has no migration side effect at require time', () => {
+  it('requiring config.js does not create the logs dir', async () => {
+    // Fresh require in a child process with a temp CCXRAY_HOME whose logs/ does
+    // not exist. The act of importing config must not touch the filesystem.
+    const home = fs.mkdtempSync(path.join(os.tmpdir(), 'ccxray-pure-'));
+    const CONFIG = path.resolve(__dirname, '..', 'server', 'config.js');
+    const snippet = `
+      const fsm = require('fs');
+      const c = require(${JSON.stringify(CONFIG)});
+      process.stdout.write(JSON.stringify({ logsDir: c.LOGS_DIR, exists: fsm.existsSync(c.LOGS_DIR) }));
+    `;
+    const env = { ...process.env };
+    delete env.LOGS_DIR;
+    delete env.STORAGE_BACKEND;
+    env.CCXRAY_HOME = home;
+    const out = await new Promise((resolve) => {
+      const ch = spawn(process.execPath, ['-e', snippet], { env, stdio: ['ignore', 'pipe', 'pipe'] });
+      let s = '';
+      ch.stdout.on('data', d => { s += d; });
+      ch.on('exit', code => resolve({ s: s.trim(), code }));
+    });
+    try {
+      assert.equal(out.code, 0, 'child should exit cleanly');
+      const r = JSON.parse(out.s);
+      assert.equal(r.exists, false, 'require(config) must NOT create LOGS_DIR — no require-time side effect');
+    } finally {
+      fs.rmSync(home, { recursive: true, force: true });
+    }
+  });
+});