diff --git a/.changeset/gvs-concurrent-slot-import.md b/.changeset/gvs-concurrent-slot-import.md
new file mode 100644
index 0000000000..073463845e
--- /dev/null
+++ b/.changeset/gvs-concurrent-slot-import.md
@@ -0,0 +1,5 @@
+---
+"pacquet": patch
+---
+
+Concurrent installs sharing a global virtual store no longer fail with `failed to remove existing directory ... prior to swap: Directory not empty`, and no longer briefly remove a package directory another process is reading.
diff --git a/.changeset/napi-global-virtual-store.md b/.changeset/napi-global-virtual-store.md
new file mode 100644
index 0000000000..384f2cc73b
--- /dev/null
+++ b/.changeset/napi-global-virtual-store.md
@@ -0,0 +1,5 @@
+---
+"@pnpm/napi": minor
+---
+
+`install` accepts `enableGlobalVirtualStore`, `globalVirtualStoreDir`, `packageExtensions` and `patchedDependencies`, and `readConfig` reports `enableGlobalVirtualStore`, `globalVirtualStoreDir`, `virtualStoreDir` and `effectiveVirtualStoreDir`. Hosts embedding the engine can now use the global virtual store, declare dependencies a package failed to declare, patch a package, and locate the virtual store instead of assuming `node_modules/.pnpm`.
diff --git a/pnpm/crates/cli/src/cli_args/deploy.rs b/pnpm/crates/cli/src/cli_args/deploy.rs
index db3c86257c..e1a9abbeb2 100644
--- a/pnpm/crates/cli/src/cli_args/deploy.rs
+++ b/pnpm/crates/cli/src/cli_args/deploy.rs
@@ -741,7 +741,7 @@ fn copy_project<ReporterT: Reporter>(
         PackageImportMethod::CloneOrCopy,
         dest,
         &output.files_map,
-        ImportIndexedDirOpts { force: true, keep_modules_dir: false },
+        ImportIndexedDirOpts { force: true, ..ImportIndexedDirOpts::default() },
     )
     .map_err(miette::Report::new)
     .wrap_err("copy project files")
diff --git a/pnpm/crates/deps-restorer/src/build_modules.rs b/pnpm/crates/deps-restorer/src/build_modules.rs
index 7957874ed5..4f04d1a4e1 100644
--- a/pnpm/crates/deps-restorer/src/build_modules.rs
+++ b/pnpm/crates/deps-restorer/src/build_modules.rs
@@ -1559,7 +1559,11 @@ fn materialize_side_effects<Reporter: self::Reporter>(
         import_method,
         pkg_dir,
         overlay,
-        ImportIndexedDirOpts { force: true, keep_modules_dir: true },
+        ImportIndexedDirOpts {
+            force: true,
+            keep_modules_dir: true,
+            ..ImportIndexedDirOpts::default()
+        },
     )
     .map_err(BuildModulesError::MaterializeSideEffects)
 }
diff --git a/pnpm/crates/deps-restorer/src/create_virtual_dir_by_snapshot.rs b/pnpm/crates/deps-restorer/src/create_virtual_dir_by_snapshot.rs
index 108d195c0b..6d4529629e 100644
--- a/pnpm/crates/deps-restorer/src/create_virtual_dir_by_snapshot.rs
+++ b/pnpm/crates/deps-restorer/src/create_virtual_dir_by_snapshot.rs
@@ -173,10 +173,12 @@ impl CreateVirtualDirBySnapshot<'_> {
         } else {
             cas_paths
         };
+        // Mutable sources can reuse a slot for different contents, so a complete import may be stale.
+        let safe_to_skip = layout.enable_global_virtual_store() && !source_is_mutable;
         let import_opts = if interrupted_build || source_is_mutable {
-            ImportIndexedDirOpts { force: true, keep_modules_dir: true }
+            ImportIndexedDirOpts { force: true, keep_modules_dir: true, safe_to_skip }
         } else {
-            ImportIndexedDirOpts::default()
+            ImportIndexedDirOpts { safe_to_skip, ..ImportIndexedDirOpts::default() }
         };
 
         let import_package = || {
diff --git a/pnpm/crates/deps-restorer/src/import_indexed_dir.rs b/pnpm/crates/deps-restorer/src/import_indexed_dir.rs
index d33d173f5b..5f47a1e8c6 100644
--- a/pnpm/crates/deps-restorer/src/import_indexed_dir.rs
+++ b/pnpm/crates/deps-restorer/src/import_indexed_dir.rs
@@ -37,6 +37,10 @@ pub struct ImportIndexedDirOpts {
     /// installed by a sibling pass must not be clobbered when the
     /// parent package is re-imported.
     pub keep_modules_dir: bool,
+    /// Whether an occupied, complete target is equivalent to this import.
+    ///
+    /// Callers must ensure that the target path uniquely identifies its contents.
+    pub safe_to_skip: bool,
 }
 
 /// Error type for [`import_indexed_dir`].
@@ -170,6 +174,7 @@ pub fn import_indexed_dir<Reporter: self::Reporter>(
             dir_path,
             cas_paths,
             opts.keep_modules_dir,
+            opts.safe_to_skip,
         )
         .inspect(|()| unquarantine()),
     }
@@ -261,6 +266,26 @@ fn marker_file(cas_paths: &HashMap<String, PathBuf>) -> Option<&str> {
     cas_paths.keys().map(String::as_str).filter(|path| *path != crate::NEEDS_BUILD_MARKER).min()
 }
 
+// Supported platforms report an occupied directory with different error kinds.
+fn is_occupied_target(error: &io::Error) -> bool {
+    matches!(
+        error.kind(),
+        io::ErrorKind::DirectoryNotEmpty
+            | io::ErrorKind::AlreadyExists
+            | io::ErrorKind::PermissionDenied,
+    )
+}
+
+// The completion marker is placed last. Verify every package file in case a completed import was
+// later damaged. The needs-build marker is transient and does not identify package contents.
+fn is_complete_import(dir_path: &Path, cas_paths: &HashMap<String, PathBuf>) -> bool {
+    marker_present(dir_path, cas_paths)
+        && cas_paths
+            .keys()
+            .filter(|entry| entry.as_str() != crate::NEEDS_BUILD_MARKER)
+            .all(|entry| dir_path.join(entry).exists())
+}
+
 /// Whether `dir_path` holds the completion marker. An empty map has no
 /// marker, so it counts as present — there is nothing to import.
 #[must_use]
@@ -310,6 +335,7 @@ fn stage_and_swap<Reporter: self::Reporter>(
     dir_path: &Path,
     cas_paths: &HashMap<String, PathBuf>,
     keep_modules_dir: bool,
+    safe_to_skip: bool,
 ) -> Result<(), ImportIndexedDirError> {
     let stage = pick_stage_path(dir_path);
     let target_modules = dir_path.join("node_modules");
@@ -370,6 +396,20 @@ fn stage_and_swap<Reporter: self::Reporter>(
         Some(_) | None => false,
     };
 
+    // 3b. Keep a complete content-addressed target instead of removing a directory that another
+    //     importer may be populating or reading. When step 3 moved `node_modules/`, continue with
+    //     the swap so that it can be restored.
+    if safe_to_skip && !nm_moved {
+        match fs::rename(&stage, dir_path) {
+            Ok(()) => return Ok(()),
+            Err(error) if is_occupied_target(&error) && is_complete_import(dir_path, cas_paths) => {
+                let _ = fs::remove_dir_all(&stage);
+                return Ok(());
+            }
+            Err(_) => {}
+        }
+    }
+
     // 4. Remove the old contents. If this fails after step 3, the
     //    staged copy of `node_modules/` is the user's only copy —
     //    try to move it back into place before bailing, and leak
diff --git a/pnpm/crates/deps-restorer/src/import_indexed_dir/tests.rs b/pnpm/crates/deps-restorer/src/import_indexed_dir/tests.rs
index 3232ffbf16..89ecc06eeb 100644
--- a/pnpm/crates/deps-restorer/src/import_indexed_dir/tests.rs
+++ b/pnpm/crates/deps-restorer/src/import_indexed_dir/tests.rs
@@ -24,9 +24,11 @@ fn cas_map(entries: &[(&str, PathBuf)]) -> HashMap<String, PathBuf> {
 }
 
 const FORCE_KEEP: ImportIndexedDirOpts =
-    ImportIndexedDirOpts { force: true, keep_modules_dir: true };
+    ImportIndexedDirOpts { force: true, keep_modules_dir: true, safe_to_skip: false };
 const FORCE_ONLY: ImportIndexedDirOpts =
-    ImportIndexedDirOpts { force: true, keep_modules_dir: false };
+    ImportIndexedDirOpts { force: true, keep_modules_dir: false, safe_to_skip: false };
+const FORCE_SHARED: ImportIndexedDirOpts =
+    ImportIndexedDirOpts { force: true, keep_modules_dir: false, safe_to_skip: true };
 
 #[test]
 fn fresh_target_links_files() {
@@ -679,3 +681,179 @@ fn marker_only_map_creates_target_and_places_marker() {
         );
     }
 }
+
+#[test]
+fn safe_to_skip_keeps_a_target_a_concurrent_importer_already_completed() {
+    let tmp = tempdir().unwrap();
+    let src_root = tmp.path().join("cas");
+    fs::create_dir_all(&src_root).unwrap();
+    let pkg_json = write_source(&src_root, "package.json", b"{\"version\":\"1.0.0\"}");
+    let index = write_source(&src_root, "index.js", b"module.exports = 1");
+    let cas = cas_map(&[("package.json", pkg_json), ("index.js", index)]);
+
+    let target = tmp.path().join("slot");
+    fs::create_dir_all(&target).unwrap();
+    fs::write(target.join("package.json"), b"{\"version\":\"1.0.0\"}").unwrap();
+    fs::write(target.join("index.js"), b"module.exports = 1").unwrap();
+
+    import_indexed_dir::<SilentReporter>(
+        &AtomicU8::new(0),
+        PackageImportMethod::Copy,
+        &target,
+        &cas,
+        FORCE_SHARED,
+    )
+    .expect("a slot another importer already completed is not a conflict");
+
+    assert_eq!(fs::read(target.join("package.json")).unwrap(), b"{\"version\":\"1.0.0\"}");
+    assert_eq!(fs::read(target.join("index.js")).unwrap(), b"module.exports = 1");
+    let strays: Vec<_> = fs::read_dir(tmp.path())
+        .unwrap()
+        .map(|entry| entry.unwrap().file_name().to_string_lossy().into_owned())
+        .filter(|name| name != "cas" && name != "slot")
+        .collect();
+    assert_eq!(strays, Vec::<String>::new(), "staging dir must be cleaned up");
+}
+
+#[test]
+fn safe_to_skip_does_not_accept_a_slot_that_is_still_being_written() {
+    let tmp = tempdir().unwrap();
+    let src_root = tmp.path().join("cas");
+    fs::create_dir_all(&src_root).unwrap();
+    let pkg_json = write_source(&src_root, "package.json", b"{\"version\":\"1.0.0\"}");
+    let index = write_source(&src_root, "index.js", b"module.exports = 1");
+    let cas = cas_map(&[("package.json", pkg_json), ("index.js", index)]);
+
+    let target = tmp.path().join("slot");
+    fs::create_dir_all(&target).unwrap();
+    fs::write(target.join("index.js"), b"half-written").unwrap();
+
+    import_indexed_dir::<SilentReporter>(
+        &AtomicU8::new(0),
+        PackageImportMethod::Copy,
+        &target,
+        &cas,
+        FORCE_SHARED,
+    )
+    .expect("an unfinished slot must be completed, not accepted");
+
+    assert_eq!(fs::read(target.join("package.json")).unwrap(), b"{\"version\":\"1.0.0\"}");
+    assert_eq!(
+        fs::read(target.join("index.js")).unwrap(),
+        b"module.exports = 1",
+        "the half-written file must be replaced, not kept",
+    );
+}
+
+#[test]
+fn safe_to_skip_still_repairs_an_incomplete_target() {
+    let tmp = tempdir().unwrap();
+    let src_root = tmp.path().join("cas");
+    fs::create_dir_all(&src_root).unwrap();
+    let pkg_json = write_source(&src_root, "package.json", b"{\"version\":\"1.0.0\"}");
+    let index = write_source(&src_root, "index.js", b"module.exports = 1");
+    let cas = cas_map(&[("package.json", pkg_json), ("index.js", index)]);
+
+    let target = tmp.path().join("slot");
+    fs::create_dir_all(&target).unwrap();
+    fs::write(target.join("package.json"), b"truncated").unwrap();
+
+    import_indexed_dir::<SilentReporter>(
+        &AtomicU8::new(0),
+        PackageImportMethod::Copy,
+        &target,
+        &cas,
+        FORCE_SHARED,
+    )
+    .expect("an incomplete slot must be repaired");
+
+    assert_eq!(fs::read(target.join("package.json")).unwrap(), b"{\"version\":\"1.0.0\"}");
+    assert_eq!(fs::read(target.join("index.js")).unwrap(), b"module.exports = 1");
+}
+
+// Windows needs retry handling while a competing importer holds file handles.
+#[cfg(unix)]
+#[test]
+fn concurrent_importers_of_one_shared_slot_both_succeed() {
+    use std::sync::{Arc, Barrier};
+
+    let tmp = tempdir().unwrap();
+    let src_root = tmp.path().join("cas");
+    fs::create_dir_all(&src_root).unwrap();
+    let pkg_json = write_source(&src_root, "package.json", b"{\"version\":\"1.0.0\"}");
+    let index = write_source(&src_root, "index.js", b"module.exports = 1");
+    let cas = Arc::new(cas_map(&[("package.json", pkg_json), ("index.js", index)]));
+
+    let target = Arc::new(tmp.path().join("slot"));
+    let barrier = Arc::new(Barrier::new(2));
+
+    let handles: Vec<_> = (0..2)
+        .map(|_| {
+            let cas = Arc::clone(&cas);
+            let target = Arc::clone(&target);
+            let barrier = Arc::clone(&barrier);
+            std::thread::spawn(move || {
+                barrier.wait();
+                import_indexed_dir::<SilentReporter>(
+                    &AtomicU8::new(0),
+                    PackageImportMethod::Copy,
+                    &target,
+                    &cas,
+                    FORCE_SHARED,
+                )
+            })
+        })
+        .collect();
+
+    for handle in handles {
+        handle.join().expect("importer thread panicked").expect("both importers must succeed");
+    }
+
+    assert_eq!(fs::read(target.join("package.json")).unwrap(), b"{\"version\":\"1.0.0\"}");
+    assert_eq!(fs::read(target.join("index.js")).unwrap(), b"module.exports = 1");
+    let strays: Vec<String> = fs::read_dir(tmp.path())
+        .unwrap()
+        .map(|entry| entry.unwrap().file_name().to_string_lossy().into_owned())
+        .filter(|name| name != "cas" && name != "slot")
+        .collect();
+    assert_eq!(strays, Vec::<String>::new(), "neither importer may leak a staging dir");
+}
+
+#[test]
+fn safe_to_skip_keeps_a_slot_whose_build_removed_the_needs_build_marker() {
+    let tmp = tempdir().unwrap();
+    let src_root = tmp.path().join("cas");
+    fs::create_dir_all(&src_root).unwrap();
+    let pkg_json = write_source(&src_root, "package.json", b"{\"version\":\"1.0.0\"}");
+    let index = write_source(&src_root, "index.js", b"module.exports = 1");
+    let needs_build = write_source(&src_root, "needs-build", b"");
+    let cas = cas_map(&[
+        ("package.json", pkg_json),
+        ("index.js", index),
+        (crate::NEEDS_BUILD_MARKER, needs_build),
+    ]);
+
+    let target = tmp.path().join("slot");
+    fs::create_dir_all(&target).unwrap();
+    fs::write(target.join("package.json"), b"{\"version\":\"1.0.0\"}").unwrap();
+    fs::write(target.join("index.js"), b"module.exports = 1").unwrap();
+    fs::write(target.join("built.node"), b"native addon").unwrap();
+
+    import_indexed_dir::<SilentReporter>(
+        &AtomicU8::new(0),
+        PackageImportMethod::Copy,
+        &target,
+        &cas,
+        FORCE_SHARED,
+    )
+    .expect("a built slot must be left alone");
+
+    assert!(
+        target.join("built.node").exists(),
+        "the build output must survive; the slot was rebuilt from the staging copy",
+    );
+    assert!(
+        !target.join(crate::NEEDS_BUILD_MARKER).exists(),
+        "the consumed needs-build marker must not be put back",
+    );
+}
diff --git a/pnpm/crates/deps-restorer/src/link_hoisted_modules.rs b/pnpm/crates/deps-restorer/src/link_hoisted_modules.rs
index 85d4694273..3f105a6c6e 100644
--- a/pnpm/crates/deps-restorer/src/link_hoisted_modules.rs
+++ b/pnpm/crates/deps-restorer/src/link_hoisted_modules.rs
@@ -289,7 +289,11 @@ fn import_node<Reporter: self::Reporter>(
         opts.import_method,
         &node.dir,
         cas_paths,
-        ImportIndexedDirOpts { force: true, keep_modules_dir: true },
+        ImportIndexedDirOpts {
+            force: true,
+            keep_modules_dir: true,
+            ..ImportIndexedDirOpts::default()
+        },
     )
     .map_err(LinkHoistedModulesError::ImportIndexedDir)
 }
diff --git a/pnpm/crates/napi/src/config.rs b/pnpm/crates/napi/src/config.rs
index 64a34e9e8c..768e747891 100644
--- a/pnpm/crates/napi/src/config.rs
+++ b/pnpm/crates/napi/src/config.rs
@@ -35,7 +35,7 @@ use dashmap::DashMap;
 use indexmap::IndexMap;
 use pacquet_config::{
     Config, GetHomeDir, Host, LinkWorkspacePackages, LoadWorkspaceYamlError, NodeLinker,
-    PackageImportMethod, default_registry,
+    PackageExtension, PackageImportMethod, default_registry,
 };
 use pacquet_network::{AuthHeaders, ProxyConfig, TlsConfig, nerf_dart, normalize_auth_key};
 use pacquet_store_dir::StoreDir;
@@ -59,6 +59,10 @@ pub struct ConfigOverlay {
     pub link_workspace_packages: Option<LinkWorkspacePackages>,
     pub package_import_method: Option<PackageImportMethod>,
     pub virtual_store_dir_max_length: Option<u64>,
+    pub enable_global_virtual_store: Option<bool>,
+    pub global_virtual_store_dir: Option<PathBuf>,
+    pub package_extensions: Option<IndexMap<String, PackageExtension>>,
+    pub patched_dependencies: Option<IndexMap<String, String>>,
     pub hoist_pattern: Option<Vec<String>>,
     pub public_hoist_pattern: Option<Vec<String>>,
     pub external_dependencies: Option<BTreeSet<String>>,
@@ -280,6 +284,24 @@ fn build_config(dir: &Path, overlay: &ConfigOverlay) -> Result<Config, LoadWorks
     if let Some(max_length) = overlay.virtual_store_dir_max_length {
         config.virtual_store_dir_max_length = max_length;
     }
+    if let Some(value) = overlay.enable_global_virtual_store {
+        config.enable_global_virtual_store = value;
+    }
+    if let Some(package_extensions) = &overlay.package_extensions {
+        config.package_extensions = Some(package_extensions.clone());
+    }
+    if let Some(patched_dependencies) = &overlay.patched_dependencies {
+        // Embedded installs resolve relative patch paths from `dir`, even without a workspace file.
+        config.patched_dependencies = Some(
+            patched_dependencies
+                .iter()
+                .map(|(key, path)| (key.clone(), dir.join(path).display().to_string()))
+                .collect(),
+        );
+        if config.workspace_dir.is_none() {
+            config.workspace_dir = Some(dir.to_path_buf());
+        }
+    }
     if let Some(hoist_pattern) = &overlay.hoist_pattern {
         config.hoist_pattern = Some(hoist_pattern.clone());
     }
@@ -403,6 +425,18 @@ fn build_config(dir: &Path, overlay: &ConfigOverlay) -> Result<Config, LoadWorks
             &overlay_default_registry(overlay),
         )));
     }
+    // Overlay fields may invalidate the path derived by `Config::current`.
+    if let Some(global_virtual_store_dir) = &overlay.global_virtual_store_dir {
+        config.global_virtual_store_dir.clone_from(global_virtual_store_dir);
+    } else if overlay.enable_global_virtual_store.is_some() || overlay.store_dir.is_some() {
+        let virtual_store_dir_explicit = config.explicit_settings.contains_key("virtualStoreDir");
+        let global_virtual_store_dir_explicit =
+            config.explicit_settings.contains_key("globalVirtualStoreDir");
+        config.apply_global_virtual_store_derivation(
+            virtual_store_dir_explicit,
+            global_virtual_store_dir_explicit,
+        );
+    }
     Ok(config)
 }
 
diff --git a/pnpm/crates/napi/src/install.rs b/pnpm/crates/napi/src/install.rs
index 1ef78906f8..9fea2604a6 100644
--- a/pnpm/crates/napi/src/install.rs
+++ b/pnpm/crates/napi/src/install.rs
@@ -90,6 +90,14 @@ pub struct InstallOptions {
     pub prefer_offline: Option<bool>,
     pub offline: Option<bool>,
     pub virtual_store_dir_max_length: Option<u32>,
+    /// Whether to use the shared global virtual store for dependency slots.
+    pub enable_global_virtual_store: Option<bool>,
+    /// Overrides the global virtual store directory.
+    pub global_virtual_store_dir: Option<String>,
+    /// Manifest fields to add to packages selected by name or version range.
+    pub package_extensions: Option<IndexMap<String, PackageExtensionInput>>,
+    /// Patch paths keyed by package selector. Relative paths resolve from `dir`.
+    pub patched_dependencies: Option<IndexMap<String, String>>,
     pub peers_suffix_max_length: Option<u32>,
     pub dedupe_peer_dependents: Option<bool>,
     pub dedupe_peers: Option<bool>,
@@ -171,6 +179,21 @@ pub struct NetworkConfigInput {
     pub user_agent: Option<String>,
 }
 
+/// Manifest fields to add to a matching package.
+#[napi(object)]
+pub struct PackageExtensionInput {
+    pub dependencies: Option<HashMap<String, String>>,
+    pub optional_dependencies: Option<HashMap<String, String>>,
+    pub peer_dependencies: Option<HashMap<String, String>>,
+    pub peer_dependencies_meta: Option<HashMap<String, PeerDependencyMetaInput>>,
+}
+
+/// Metadata for a peer dependency.
+#[napi(object)]
+pub struct PeerDependencyMetaInput {
+    pub optional: Option<bool>,
+}
+
 /// `peerDependencyRules` input. Mirrors `PeerDependencyRules` in `index.d.ts`.
 #[napi(object)]
 pub struct PeerDependencyRulesInput {
@@ -548,6 +571,42 @@ fn build_overlay(options: &InstallOptions) -> napi::Result<ConfigOverlay> {
             .as_deref()
             .and_then(parse_import_method),
         virtual_store_dir_max_length: options.virtual_store_dir_max_length.map(u64::from),
+        enable_global_virtual_store: options.enable_global_virtual_store,
+        global_virtual_store_dir: options.global_virtual_store_dir.as_ref().map(PathBuf::from),
+        package_extensions: options.package_extensions.as_ref().map(|extensions| {
+            extensions
+                .iter()
+                .map(|(selector, extension)| {
+                    let to_sorted = |map: &Option<HashMap<String, String>>| {
+                        map.as_ref()
+                            .map(|map| map.iter().map(|(k, v)| (k.clone(), v.clone())).collect())
+                    };
+                    (
+                        selector.clone(),
+                        pacquet_config::PackageExtension {
+                            dependencies: to_sorted(&extension.dependencies),
+                            optional_dependencies: to_sorted(&extension.optional_dependencies),
+                            peer_dependencies: to_sorted(&extension.peer_dependencies),
+                            peer_dependencies_meta: extension.peer_dependencies_meta.as_ref().map(
+                                |meta| {
+                                    meta.iter()
+                                        .map(|(name, entry)| {
+                                            (
+                                                name.clone(),
+                                                pacquet_config::PeerDependencyMeta {
+                                                    optional: entry.optional,
+                                                },
+                                            )
+                                        })
+                                        .collect()
+                                },
+                            ),
+                        },
+                    )
+                })
+                .collect()
+        }),
+        patched_dependencies: options.patched_dependencies.clone(),
         hoist_pattern: options.hoist_pattern.clone(),
         public_hoist_pattern: options.public_hoist_pattern.clone(),
         external_dependencies: options
diff --git a/pnpm/crates/napi/src/install/tests.rs b/pnpm/crates/napi/src/install/tests.rs
index ef7d379f2b..84f73fad2f 100644
--- a/pnpm/crates/napi/src/install/tests.rs
+++ b/pnpm/crates/napi/src/install/tests.rs
@@ -531,6 +531,10 @@ fn install_options() -> InstallOptions {
         prefer_offline: None,
         offline: None,
         virtual_store_dir_max_length: None,
+        enable_global_virtual_store: None,
+        global_virtual_store_dir: None,
+        package_extensions: None,
+        patched_dependencies: None,
         peers_suffix_max_length: None,
         dedupe_peer_dependents: None,
         dedupe_peers: None,
diff --git a/pnpm/crates/napi/src/read_config.rs b/pnpm/crates/napi/src/read_config.rs
index db40e43086..e38cb803a6 100644
--- a/pnpm/crates/napi/src/read_config.rs
+++ b/pnpm/crates/napi/src/read_config.rs
@@ -57,6 +57,14 @@ pub struct ResolvedConfig {
     pub store_dir: String,
     pub cache_dir: String,
     pub virtual_store_dir_max_length: u32,
+    /// Whether the resolved configuration uses the global virtual store.
+    pub enable_global_virtual_store: bool,
+    /// Shared virtual-store root.
+    pub global_virtual_store_dir: String,
+    /// Project-local virtual-store directory.
+    pub virtual_store_dir: String,
+    /// Virtual-store directory used by this configuration and recorded in `.modules.yaml`.
+    pub effective_virtual_store_dir: String,
     pub network_concurrency: u32,
     pub max_sockets: Option<u32>,
     pub fetch_retries: u32,
@@ -148,6 +156,10 @@ fn project_config(config: &pacquet_config::Config) -> ResolvedConfig {
         cache_dir: config.cache_dir.display().to_string(),
         virtual_store_dir_max_length: u32::try_from(config.virtual_store_dir_max_length)
             .unwrap_or(u32::MAX),
+        enable_global_virtual_store: config.enable_global_virtual_store,
+        global_virtual_store_dir: config.global_virtual_store_dir.display().to_string(),
+        virtual_store_dir: config.virtual_store_dir.display().to_string(),
+        effective_virtual_store_dir: config.effective_virtual_store_dir().display().to_string(),
         network_concurrency: u32::try_from(config.network_concurrency).unwrap_or(u32::MAX),
         max_sockets: config.max_sockets.map(|value| u32::try_from(value).unwrap_or(u32::MAX)),
         fetch_retries: config.fetch_retries,
diff --git a/pnpm/crates/package-manager/src/patch.rs b/pnpm/crates/package-manager/src/patch.rs
index 97c9d5cb1d..1781c1c3fc 100644
--- a/pnpm/crates/package-manager/src/patch.rs
+++ b/pnpm/crates/package-manager/src/patch.rs
@@ -282,7 +282,7 @@ impl WritePackageForPatch<'_> {
                 PackageImportMethod::CloneOrCopy,
                 dest,
                 &cas_paths,
-                ImportIndexedDirOpts { force: true, keep_modules_dir: false },
+                ImportIndexedDirOpts { force: true, ..ImportIndexedDirOpts::default() },
             )
             .map_err(WritePackageForPatchError::ImportIndexedDir)
         }
diff --git a/pnpm/npm/napi/index.d.ts b/pnpm/npm/napi/index.d.ts
index ac62ea6972..cce26b1906 100644
--- a/pnpm/npm/napi/index.d.ts
+++ b/pnpm/npm/napi/index.d.ts
@@ -104,6 +104,14 @@ export interface SharedEngineOptions {
   cacheDir?: string
 }
 
+/** Manifest fields to add to a matching package. */
+export interface PackageExtension {
+  dependencies?: Record<string, string>
+  optionalDependencies?: Record<string, string>
+  peerDependencies?: Record<string, string>
+  peerDependenciesMeta?: Record<string, { optional?: boolean }>
+}
+
 export interface InstallOptions extends SharedEngineOptions {
   /** Lockfile / workspace root directory. */
   dir: string
@@ -132,6 +140,14 @@ export interface InstallOptions extends SharedEngineOptions {
   preferOffline?: boolean
   offline?: boolean
   virtualStoreDirMaxLength?: number
+  /** Whether to use the shared global virtual store for dependency slots. */
+  enableGlobalVirtualStore?: boolean
+  /** Overrides the global virtual store directory. */
+  globalVirtualStoreDir?: string
+  /** Manifest fields to add to packages selected by name or version range. */
+  packageExtensions?: Record<string, PackageExtension>
+  /** Patch paths keyed by package selector. Relative paths resolve from `dir`. */
+  patchedDependencies?: Record<string, string>
   peersSuffixMaxLength?: number
   dedupePeerDependents?: boolean
   /**
@@ -386,6 +402,14 @@ export interface ResolvedConfig {
   storeDir: string
   cacheDir: string
   virtualStoreDirMaxLength: number
+  /** Whether the resolved configuration uses the global virtual store. */
+  enableGlobalVirtualStore: boolean
+  /** Shared virtual-store root. */
+  globalVirtualStoreDir: string
+  /** Project-local virtual-store directory. */
+  virtualStoreDir: string
+  /** Virtual-store directory used by this configuration and recorded in `.modules.yaml`. */
+  effectiveVirtualStoreDir: string
   networkConcurrency: number
   maxSockets?: number
   fetchRetries: number