diff --git a/docs/recipe-contract.md b/docs/recipe-contract.md
index b9ceabdc2..dc013969d 100644
--- a/docs/recipe-contract.md
+++ b/docs/recipe-contract.md
@@ -204,7 +204,9 @@ the mounted plugin slug.
 Supported `loadAs` values:
 
 - `plugin`: mount below `/wordpress/wp-content/plugins/<slug>` and activate when
-  `activate` is not `false`.
+  `activate` is not `false`. Composer autoloaders are preloaded only for these
+  active plugin inputs; an inactive plugin is mounted without executing its
+  `vendor/autoload.php`.
 - `mu-plugin`: mount below
   `/wordpress/wp-content/mu-plugins/wp-codebox-runtime/<slug>` and load through
   WP Codebox's generated MU-plugin loader. Use this for sandbox runtime
diff --git a/package.json b/package.json
index 74779eb76..31d59b08d 100644
--- a/package.json
+++ b/package.json
@@ -234,6 +234,7 @@
     "test:composer-package-overlay-revision": "tsx scripts/composer-backed-source-hydration-smoke.ts",
     "test:composer-package-overlay-autoload-layout": "tsx scripts/composer-package-overlay-autoload-layout-smoke.ts",
     "test:composer-installed-versions-loader-order": "tsx scripts/composer-installed-versions-loader-order-smoke.ts",
+    "test:recipe-extra-plugin-composer-autoloaders": "tsx tests/recipe-extra-plugin-composer-autoloaders.test.ts",
     "test:runtime-preset-registry": "tsx tests/runtime-preset-registry.test.ts",
     "test:generic-ability-runtime-run": "tsx tests/generic-ability-runtime-run.test.ts",
     "test:provider-runtime-contracts": "tsx tests/provider-runtime-contracts.test.ts",
diff --git a/packages/cli/src/recipe-sources.ts b/packages/cli/src/recipe-sources.ts
index 5058374ad..7ed060c70 100644
--- a/packages/cli/src/recipe-sources.ts
+++ b/packages/cli/src/recipe-sources.ts
@@ -1796,7 +1796,7 @@ echo wp_json_encode(array('command' => 'install-mu-plugins', 'plugins' => $plugi
 
 export function installPluginComposerAutoloadersCode(extraPlugins: PreparedExtraPlugin[]): string | null {
   const plugins = extraPlugins
-    .filter((plugin) => plugin.loadAs === "plugin")
+    .filter((plugin) => plugin.loadAs === "plugin" && plugin.activate)
     .map((plugin) => plugin.pluginFile)
 
   if (plugins.length === 0) {
@@ -1804,6 +1804,7 @@ export function installPluginComposerAutoloadersCode(extraPlugins: PreparedExtra
   }
 
   return `$plugins = ${JSON.stringify(plugins)};
+$autoloaders = array();
 if (!is_dir(WPMU_PLUGIN_DIR) && !mkdir(WPMU_PLUGIN_DIR, 0777, true) && !is_dir(WPMU_PLUGIN_DIR)) {
     throw new RuntimeException('Could not create mu-plugins directory.');
 }
@@ -1828,16 +1829,20 @@ foreach ($plugins as $plugin) {
     }
     $package_autoload = WP_PLUGIN_DIR . '/' . $plugin_dir . '/vendor/autoload_packages.php';
     if (is_file($package_autoload)) {
-        $lines[] = "require_once WP_PLUGIN_DIR . '/" . str_replace("'", "\\'", $plugin_dir) . "/vendor/autoload_packages.php';";
+        $autoload_path = $plugin_dir . '/vendor/autoload_packages.php';
+        $autoloaders[] = $autoload_path;
+        $lines[] = "require_once WP_PLUGIN_DIR . '/" . str_replace("'", "\\'", $autoload_path) . "';";
         continue;
     }
     $autoload = WP_PLUGIN_DIR . '/' . $plugin_dir . '/vendor/autoload.php';
     if (is_file($autoload)) {
-        $lines[] = "require_once WP_PLUGIN_DIR . '/" . str_replace("'", "\\'", $plugin_dir) . "/vendor/autoload.php';";
+        $autoload_path = $plugin_dir . '/vendor/autoload.php';
+        $autoloaders[] = $autoload_path;
+        $lines[] = "require_once WP_PLUGIN_DIR . '/" . str_replace("'", "\\'", $autoload_path) . "';";
     }
 }
 if (false === file_put_contents($loader, implode("\n", $lines) . "\n")) {
     throw new RuntimeException('Could not write WP Codebox Composer autoloader loader.');
 }
-echo wp_json_encode(array('command' => 'install-composer-autoloaders', 'plugins' => $plugins, 'loader' => $loader), JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);`
+echo wp_json_encode(array('command' => 'install-composer-autoloaders', 'plugins' => $plugins, 'autoloaders' => $autoloaders, 'loader' => $loader), JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);`
 }
diff --git a/tests/recipe-extra-plugin-composer-autoloaders.test.ts b/tests/recipe-extra-plugin-composer-autoloaders.test.ts
new file mode 100644
index 000000000..81802e17a
--- /dev/null
+++ b/tests/recipe-extra-plugin-composer-autoloaders.test.ts
@@ -0,0 +1,78 @@
+import assert from "node:assert/strict"
+import { execFile as execFileCallback } from "node:child_process"
+import { mkdir, mkdtemp, rm, writeFile } from "node:fs/promises"
+import { tmpdir } from "node:os"
+import { join } from "node:path"
+import { promisify } from "node:util"
+
+import { installPluginComposerAutoloadersCode, type PreparedExtraPlugin } from "../packages/cli/src/recipe-sources.js"
+
+const execFile = promisify(execFileCallback)
+const root = await mkdtemp(join(tmpdir(), "wp-codebox-extra-plugin-autoloaders-"))
+const pluginsDir = join(root, "plugins")
+const muPluginsDir = join(root, "mu-plugins")
+
+function plugin(slug: string, activate: boolean): PreparedExtraPlugin {
+  return {
+    source: join(pluginsDir, slug),
+    slug,
+    target: `/wordpress/wp-content/plugins/${slug}`,
+    pluginFile: `${slug}/${slug}.php`,
+    activate,
+    loadAs: "plugin",
+    cleanupPaths: [],
+    provenance: { kind: "local", original: join(pluginsDir, slug) },
+  }
+}
+
+try {
+  await mkdir(join(pluginsDir, "active-provider", "vendor"), { recursive: true })
+  await mkdir(join(pluginsDir, "inactive-plugin", "vendor"), { recursive: true })
+  await mkdir(join(pluginsDir, "inactive-plugin", "tests"), { recursive: true })
+  await mkdir(muPluginsDir, { recursive: true })
+
+  await writeFile(join(pluginsDir, "active-provider", "vendor", "autoload.php"), "<?php function wp_codebox_active_provider_loaded() { return true; }\n")
+  await writeFile(join(pluginsDir, "inactive-plugin", "composer.json"), JSON.stringify({
+    autoload: { "psr-4": { "InactivePlugin\\\\": "src/" } },
+    "autoload-dev": { files: ["tests/autoload-dev.php"] },
+  }))
+  await writeFile(join(pluginsDir, "inactive-plugin", "tests", "autoload-dev.php"), "<?php function wp_codebox_inactive_plugin_dev_sentinel() { return true; }\n")
+  await writeFile(join(pluginsDir, "inactive-plugin", "vendor", "autoload.php"), "<?php require_once dirname(__DIR__) . '/tests/autoload-dev.php';\n")
+
+  const installCode = installPluginComposerAutoloadersCode([
+    plugin("active-provider", true),
+    plugin("inactive-plugin", false),
+  ])
+  assert.ok(installCode)
+  assert.doesNotMatch(installCode, /inactive-plugin/, "inactive plugin inputs are absent from the generated preload contract")
+
+  const php = `
+function wp_json_encode($value, $options = 0) { return json_encode($value, $options); }
+define('ABSPATH', ${JSON.stringify(`${root}/`)});
+define('WP_PLUGIN_DIR', ${JSON.stringify(pluginsDir)});
+define('WPMU_PLUGIN_DIR', ${JSON.stringify(muPluginsDir)});
+${installCode}
+echo "\n---RESULT---\n";
+require WPMU_PLUGIN_DIR . '/wp-codebox-composer-autoloaders.php';
+echo json_encode(array(
+    'active_provider_loaded' => function_exists('wp_codebox_active_provider_loaded'),
+    'inactive_dev_sentinel_loaded' => function_exists('wp_codebox_inactive_plugin_dev_sentinel'),
+));
+`
+  const { stdout } = await execFile("php", ["-r", php])
+  const [evidenceJson, resultJson] = stdout.split("\n---RESULT---\n")
+  assert.deepEqual(JSON.parse(evidenceJson), {
+    command: "install-composer-autoloaders",
+    plugins: ["active-provider/active-provider.php"],
+    autoloaders: ["active-provider/vendor/autoload.php"],
+    loader: join(muPluginsDir, "wp-codebox-composer-autoloaders.php"),
+  }, "setup evidence names each intentionally preloaded autoloader")
+  assert.deepEqual(JSON.parse(resultJson), {
+    active_provider_loaded: true,
+    inactive_dev_sentinel_loaded: false,
+  })
+
+  console.log("recipe extra plugin composer autoloaders ok")
+} finally {
+  await rm(root, { recursive: true, force: true })
+}