diff --git a/store/store.go b/fs/fs.go
similarity index 75%
rename from store/store.go
rename to fs/fs.go
index f5aa8df..6bdf4f5 100644
--- a/store/store.go
+++ b/fs/fs.go
@@ -1,6 +1,6 @@
 // Package store defines storage interfaces and a filesystem-backed
 // implementation used by the 9P server.
-package store
+package fs
 
 import (
 	"context"
@@ -8,8 +8,8 @@ import (
 	"time"
 )
 
-// StoreEntry is an open handle to a single named blob.
-type StoreEntry interface {
+// File is an open handle to a single named blob.
+type File interface {
 	Stat() (os.FileInfo, error)
 	Read() ([]byte, error)
 	Write(data []byte) error
@@ -22,11 +22,11 @@ type StoreEntry interface {
 	Async() bool
 }
 
-// Store is a named collection of entries.
-type Store interface {
+// FileTree is a named collection of entries.
+type FileTree interface {
 	Stat(name string) (os.FileInfo, error)
 	List() ([]os.DirEntry, error)
-	Open(name string) (StoreEntry, error)
+	Open(name string) (File, error)
 	Create(name string) error
 	Delete(name string) error
 	Rename(oldName, newName string) error
@@ -41,8 +41,8 @@ type Runnable interface {
 	LogInfo() (length int, vers uint32)
 }
 
-// EntryConfig implements StoreEntry via function pointers.
-type EntryConfig struct {
+// FileConfig implements File via function pointers.
+type FileConfig struct {
 	StatFn         func() (os.FileInfo, error)
 	ReadFn         func() ([]byte, error)
 	WriteFn        func([]byte) error
@@ -52,15 +52,15 @@ type EntryConfig struct {
 	Async_         bool
 }
 
-func (e *EntryConfig) Stat() (os.FileInfo, error)                              { return e.StatFn() }
-func (e *EntryConfig) Read() ([]byte, error)                                   { return e.ReadFn() }
-func (e *EntryConfig) Write(data []byte) error                                 { return e.WriteFn(data) }
-func (e *EntryConfig) BlockingRead(ctx context.Context, base string) ([]byte, string, error) {
+func (e *FileConfig) Stat() (os.FileInfo, error)                              { return e.StatFn() }
+func (e *FileConfig) Read() ([]byte, error)                                   { return e.ReadFn() }
+func (e *FileConfig) Write(data []byte) error                                 { return e.WriteFn(data) }
+func (e *FileConfig) BlockingRead(ctx context.Context, base string) ([]byte, string, error) {
 	return e.BlockingReadFn(ctx, base)
 }
-func (e *EntryConfig) OneShot() bool    { return e.OneShot_ }
-func (e *EntryConfig) IsBlocking() bool { return e.IsBlocking_ }
-func (e *EntryConfig) Async() bool      { return e.Async_ }
+func (e *FileConfig) OneShot() bool    { return e.OneShot_ }
+func (e *FileConfig) IsBlocking() bool { return e.IsBlocking_ }
+func (e *FileConfig) Async() bool      { return e.Async_ }
 
 // SyntheticFileInfo implements os.FileInfo for entries with no backing file.
 type SyntheticFileInfo struct {
diff --git a/store/store_test.go b/fs/fs_test.go
similarity index 89%
rename from store/store_test.go
rename to fs/fs_test.go
index 8710d36..5de6a73 100644
--- a/store/store_test.go
+++ b/fs/fs_test.go
@@ -1,4 +1,4 @@
-package store_test
+package fs_test
 
 import (
 	"fmt"
@@ -9,7 +9,7 @@ import (
 	"testing"
 
 	olog "ollie/pkg/log"
-	"olliesrv/store"
+	fs "olliesrv/fs"
 )
 
 // --- stub agent.Core ---
@@ -28,7 +28,7 @@ func seedSkill(t *testing.T, base, name string) {
 }
 
 // storeRead is a test helper: Open + Read.
-func storeRead(t *testing.T, s store.Store, name string) []byte {
+func storeRead(t *testing.T, s fs.FileTree, name string) []byte {
 	t.Helper()
 	e, err := s.Open(name)
 	if err != nil {
@@ -42,7 +42,7 @@ func storeRead(t *testing.T, s store.Store, name string) []byte {
 }
 
 // storeWrite is a test helper: Open + Write.
-func storeWrite(t *testing.T, s store.Store, name string, data []byte) {
+func storeWrite(t *testing.T, s fs.FileTree, name string, data []byte) {
 	t.Helper()
 	e, err := s.Open(name)
 	if err != nil {
@@ -55,7 +55,7 @@ func storeWrite(t *testing.T, s store.Store, name string, data []byte) {
 
 // --- contract checks ---
 
-func checkReadableContract(t *testing.T, s store.Store, name string) {
+func checkReadableContract(t *testing.T, s fs.FileTree, name string) {
 	t.Helper()
 	fi, err := s.Stat(name)
 	if err != nil {
@@ -89,7 +89,7 @@ func checkReadableContract(t *testing.T, s store.Store, name string) {
 	}
 }
 
-func checkReadWriteContract(t *testing.T, s store.Store, name string) {
+func checkReadWriteContract(t *testing.T, s fs.FileTree, name string) {
 	t.Helper()
 	want := []byte("hello")
 	e, err := s.Open(name)
@@ -120,7 +120,7 @@ func checkReadWriteContract(t *testing.T, s store.Store, name string) {
 	checkReadableContract(t, s, name)
 }
 
-func checkStoreContract(t *testing.T, s store.Store, name string) {
+func checkStoreContract(t *testing.T, s fs.FileTree, name string) {
 	t.Helper()
 	if err := s.Create(name); err != nil {
 		t.Fatalf("Create: %v", err)
@@ -157,18 +157,18 @@ func checkStoreContract(t *testing.T, s store.Store, name string) {
 // ===== FlatDir =====
 
 func TestFlatDirContract(t *testing.T) {
-	checkStoreContract(t, store.NewDirStore([]string{t.TempDir()}, 0644), "test-file")
+	checkStoreContract(t, fs.NewTree([]string{t.TempDir()}, 0644), "test-file")
 }
 
 func TestFlatDirCreateMkdirError(t *testing.T) {
-	fd := store.NewDirStore([]string{"/nonexistent/path"}, 0644)
+	fd := fs.NewTree([]string{"/nonexistent/path"}, 0644)
 	if err := fd.Create("f"); err == nil {
 		t.Error("Create should fail when dir doesn't exist")
 	}
 }
 
 func TestFlatDirPutMkdirError(t *testing.T) {
-	fd := store.NewDirStore([]string{"/nonexistent/path"}, 0644)
+	fd := fs.NewTree([]string{"/nonexistent/path"}, 0644)
 	e, err := fd.Open("f")
 	if err != nil {
 		t.Fatalf("Open: %v", err)
@@ -185,7 +185,7 @@ func TestSkillStoreContract(t *testing.T) {
 	t.Setenv("OLLIE_SKILLS_PATH", dir)
 	seedSkill(t, dir, "test-skill")
 
-	s := store.NewSkillStore()
+	s := fs.NewSkillStore()
 
 	// Rename (needs seeded skill with valid front matter)
 	seedSkill(t, dir, "rename-src")
@@ -239,7 +239,7 @@ func TestSkillStoreContract(t *testing.T) {
 
 	// Create calls through injected mkdirAll + writeFile
 	var createdDir, createdFile string
-	s2 := store.NewSkillStoreWith(store.SkillStoreConfig{
+	s2 := fs.NewSkillStoreWith(fs.SkillStoreConfig{
 		Dirs:      []string{dir},
 		MkdirAll:  func(p string, _ os.FileMode) error { createdDir = p; return nil },
 		WriteFile: func(p string, _ []byte, _ os.FileMode) error { createdFile = p; return nil },
@@ -255,7 +255,7 @@ func TestSkillStoreContract(t *testing.T) {
 	}
 
 	// Create mkdirAll error
-	s3 := store.NewSkillStoreWith(store.SkillStoreConfig{
+	s3 := fs.NewSkillStoreWith(fs.SkillStoreConfig{
 		Dirs:     []string{dir},
 		MkdirAll: func(string, os.FileMode) error { return fmt.Errorf("denied") },
 	})
diff --git a/store/memory.go b/fs/memory.go
similarity index 92%
rename from store/memory.go
rename to fs/memory.go
index 73d7024..21e88ac 100644
--- a/store/memory.go
+++ b/fs/memory.go
@@ -1,4 +1,4 @@
-package store
+package fs
 
 import (
 	"context"
@@ -7,7 +7,7 @@ import (
 	"sync"
 )
 
-// MemoryStore is an in-memory key/value store implementing Store.
+// MemoryStore is an in-memory key/value store implementing FileTree.
 // Values are []byte blobs held in RAM; nothing is persisted to disk.
 // All operations are safe for concurrent use.
 type MemoryStore struct {
@@ -34,7 +34,7 @@ func (m *MemoryStore) Set(key string, value []byte) {
 	m.mu.Unlock()
 }
 
-// --- Store interface ---
+// --- FileTree interface ---
 
 func (m *MemoryStore) Stat(name string) (os.FileInfo, error) {
 	m.mu.RLock()
@@ -57,11 +57,11 @@ func (m *MemoryStore) List() ([]os.DirEntry, error) {
 	return entries, nil
 }
 
-func (m *MemoryStore) Open(name string) (StoreEntry, error) {
+func (m *MemoryStore) Open(name string) (File, error) {
 	notBlocking := func(context.Context, string) ([]byte, string, error) {
 		return nil, "", fmt.Errorf("blocking read not supported")
 	}
-	return &EntryConfig{
+	return &FileConfig{
 		StatFn: func() (os.FileInfo, error) { return m.Stat(name) },
 		ReadFn: func() ([]byte, error) {
 			m.mu.RLock()
diff --git a/store/root.go b/fs/root.go
similarity index 83%
rename from store/root.go
rename to fs/root.go
index cdf99c1..ae3fa51 100644
--- a/store/root.go
+++ b/fs/root.go
@@ -1,4 +1,4 @@
-package store
+package fs
 
 import (
 	"context"
@@ -10,8 +10,8 @@ import (
 	"ollie/pkg/paths"
 )
 
-// NewRootStore returns a read-only Store for synthetic root-level files.
-func NewRootStore() *DirStore {
+// NewRootStore returns a read-only FileTree for synthetic root-level files.
+func NewRootStore() *Tree {
 	helpPath := paths.CfgDir() + "/help.md"
 	entries := map[string]func() ([]byte, error){
 		"backends": func() ([]byte, error) {
@@ -26,7 +26,7 @@ func NewRootStore() *DirStore {
 	}
 	readOnly := func([]byte) error { return fmt.Errorf("read-only") }
 
-	return NewDirStore(nil, 0444,
+	return NewTree(nil, 0444,
 		WithReadOnly(),
 		WithResolver(func(_ []string, name string) (string, error) {
 			if _, ok := entries[name]; ok {
@@ -40,12 +40,12 @@ func NewRootStore() *DirStore {
 				FileEntry("help", 0444),
 			}, nil
 		}),
-		WithOpener(func(_ []string, name string) (StoreEntry, error) {
+		WithOpener(func(_ []string, name string) (File, error) {
 			readFn, ok := entries[name]
 			if !ok {
 				return nil, fmt.Errorf("%s: not found", name)
 			}
-			return &EntryConfig{
+			return &FileConfig{
 				StatFn:         func() (os.FileInfo, error) { return &SyntheticFileInfo{Name_: name, Mode_: 0444}, nil },
 				ReadFn:         readFn,
 				WriteFn:        readOnly,
diff --git a/store/skill.go b/fs/skill.go
similarity index 93%
rename from store/skill.go
rename to fs/skill.go
index 57c6807..8994a01 100644
--- a/store/skill.go
+++ b/fs/skill.go
@@ -1,4 +1,4 @@
-package store
+package fs
 
 import (
 	"fmt"
@@ -11,9 +11,9 @@ import (
 	"ollie/pkg/skills"
 )
 
-// NewSkillStore returns a DirStore configured for the skill directory layout.
+// NewSkillStore returns a Tree configured for the skill directory layout.
 // Skills are directories containing SKILL.md; virtual names are "skillname.md".
-func NewSkillStore() *DirStore {
+func NewSkillStore() *Tree {
 	return NewSkillStoreWith(SkillStoreConfig{})
 }
 
@@ -29,7 +29,7 @@ type SkillStoreConfig struct {
 	Rename    func(string, string) error
 }
 
-func NewSkillStoreWith(cfg SkillStoreConfig) *DirStore {
+func NewSkillStoreWith(cfg SkillStoreConfig) *Tree {
 	if cfg.Dirs == nil {
 		cfg.Dirs = skillDirs()
 	}
@@ -57,7 +57,7 @@ func NewSkillStoreWith(cfg SkillStoreConfig) *DirStore {
 
 	ss := &skillHelper{cfg: cfg}
 
-	return NewDirStore(cfg.Dirs, 0644,
+	return NewTree(cfg.Dirs, 0644,
 		WithIndex(ss.index),
 		WithResolver(ss.resolve),
 		WithLister(ss.list),
@@ -157,7 +157,7 @@ func (ss *skillHelper) rename(_ []string, old, new string) error {
 	return fmt.Errorf("skill not found: %s", oldSkill)
 }
 
-func (ss *skillHelper) index(_ Store) ([]byte, error) {
+func (ss *skillHelper) index(_ FileTree) ([]byte, error) {
 	var sb strings.Builder
 	for _, m := range ss.listSkills() {
 		fmt.Fprintf(&sb, "## %s\n", m.Name)
diff --git a/store/filestore.go b/fs/synth.go
similarity index 86%
rename from store/filestore.go
rename to fs/synth.go
index af70b47..f0317af 100644
--- a/store/filestore.go
+++ b/fs/synth.go
@@ -1,4 +1,4 @@
-package store
+package fs
 
 import (
 	"context"
@@ -6,7 +6,7 @@ import (
 	"os"
 )
 
-// FileSpec describes a single synthetic file exposed by a DirStore.
+// FileSpec describes a single synthetic file exposed by a Tree.
 type FileSpec struct {
 	Name    string
 	Mode    os.FileMode
@@ -18,8 +18,8 @@ type FileSpec struct {
 	Async   bool                                                                               // true = writes dispatched asynchronously
 }
 
-// NewFileStore creates a DirStore backed by a table of FileSpecs (synthetic files).
-func NewFileStore(specs []FileSpec) *DirStore {
+// NewSynth creates a Tree backed by a table of FileSpecs (synthetic files).
+func NewSynth(specs []FileSpec) *Tree {
 	index := make(map[string]int, len(specs))
 	for i, s := range specs {
 		index[s.Name] = i
@@ -33,7 +33,7 @@ func NewFileStore(specs []FileSpec) *DirStore {
 		return &specs[i], true
 	}
 
-	return NewDirStore(nil, 0,
+	return NewTree(nil, 0,
 		WithLister(func(_ []string) ([]os.DirEntry, error) {
 			entries := make([]os.DirEntry, len(specs))
 			for i, s := range specs {
@@ -41,7 +41,7 @@ func NewFileStore(specs []FileSpec) *DirStore {
 			}
 			return entries, nil
 		}),
-		WithOpener(func(_ []string, name string) (StoreEntry, error) {
+		WithOpener(func(_ []string, name string) (File, error) {
 			spec, ok := lookup(name)
 			if !ok {
 				return nil, fmt.Errorf("%s: not found", name)
@@ -56,7 +56,7 @@ func NewFileStore(specs []FileSpec) *DirStore {
 			if spec.Wait != nil {
 				waitFn = spec.Wait
 			}
-			return &EntryConfig{
+			return &FileConfig{
 				StatFn: func() (os.FileInfo, error) {
 					var size int64
 					if spec.Size != nil {
diff --git a/store/tool.go b/fs/tool.go
similarity index 95%
rename from store/tool.go
rename to fs/tool.go
index a90e9e1..05a9d7a 100644
--- a/store/tool.go
+++ b/fs/tool.go
@@ -1,4 +1,4 @@
-package store
+package fs
 
 import (
 	"fmt"
@@ -6,7 +6,7 @@ import (
 )
 
 // ToolIndex generates a tool index from a store's file listing.
-func ToolIndex(s Store) ([]byte, error) {
+func ToolIndex(s FileTree) ([]byte, error) {
 	entries, err := s.List()
 	if err != nil {
 		return nil, err
diff --git a/store/dirstore.go b/fs/tree.go
similarity index 68%
rename from store/dirstore.go
rename to fs/tree.go
index 63d3d89..323a474 100644
--- a/store/dirstore.go
+++ b/fs/tree.go
@@ -1,4 +1,4 @@
-package store
+package fs
 
 import (
 	"context"
@@ -7,103 +7,103 @@ import (
 	"path/filepath"
 )
 
-// DirStore is a configurable filesystem-backed Store.
+// Tree is a configurable filesystem-backed FileTree.
 // It supports single or multiple directories (union), read-only mode,
 // a synthetic index entry, subdirectory operations, custom path resolution,
 // and mounting child DirStores at names (sub-stores).
-type DirStore struct {
-	dirs      []string
+type Tree struct {
+	Tree      []string
 	perm      os.FileMode
 	readOnly  bool
-	indexFn   func(Store) ([]byte, error)
+	indexFn   func(FileTree) ([]byte, error)
 	resolveFn func([]string, string) (string, error)
 	listFn    func([]string) ([]os.DirEntry, error)
 	createFn  func([]string, string, os.FileMode) error
 	deleteFn  func([]string, string) error
 	renameFn  func([]string, string, string) error
-	openFn    func([]string, string) (StoreEntry, error)
+	openFn    func([]string, string) (File, error)
 	statFn    func([]string, string) (os.FileInfo, error)
-	listDirFn func([]string, string) ([]os.DirEntry, error)
-	children  map[string]*DirStore
+	readdirFn func([]string, string) ([]os.DirEntry, error)
+	children  map[string]*Tree
 }
 
-// DirOption configures a DirStore.
-type DirOption func(*DirStore)
+// Option configures a Tree.
+type Option func(*Tree)
 
 // WithReadOnly makes the store reject writes, creates, deletes, and renames.
-func WithReadOnly() DirOption { return func(d *DirStore) { d.readOnly = true } }
+func WithReadOnly() Option { return func(d *Tree) { d.readOnly = true } }
 
 // WithIndex adds a synthetic read-only "idx" entry whose content is
 // generated by calling fn with the store itself.
-func WithIndex(fn func(Store) ([]byte, error)) DirOption {
-	return func(d *DirStore) { d.indexFn = fn }
+func WithIndex(fn func(FileTree) ([]byte, error)) Option {
+	return func(d *Tree) { d.indexFn = fn }
 }
 
 // WithResolver overrides how virtual names map to filesystem paths.
-func WithResolver(fn func(dirs []string, name string) (string, error)) DirOption {
-	return func(d *DirStore) { d.resolveFn = fn }
+func WithResolver(fn func(dirs []string, name string) (string, error)) Option {
+	return func(d *Tree) { d.resolveFn = fn }
 }
 
 // WithLister overrides how the store lists its entries.
-func WithLister(fn func(dirs []string) ([]os.DirEntry, error)) DirOption {
-	return func(d *DirStore) { d.listFn = fn }
+func WithLister(fn func(dirs []string) ([]os.DirEntry, error)) Option {
+	return func(d *Tree) { d.listFn = fn }
 }
 
 // WithCreator overrides file creation logic.
-func WithCreator(fn func(dirs []string, name string, perm os.FileMode) error) DirOption {
-	return func(d *DirStore) { d.createFn = fn }
+func WithCreator(fn func(dirs []string, name string, perm os.FileMode) error) Option {
+	return func(d *Tree) { d.createFn = fn }
 }
 
 // WithDeleter overrides file deletion logic.
-func WithDeleter(fn func(dirs []string, name string) error) DirOption {
-	return func(d *DirStore) { d.deleteFn = fn }
+func WithDeleter(fn func(dirs []string, name string) error) Option {
+	return func(d *Tree) { d.deleteFn = fn }
 }
 
 // WithRenamer overrides rename logic.
-func WithRenamer(fn func(dirs []string, old, new string) error) DirOption {
-	return func(d *DirStore) { d.renameFn = fn }
+func WithRenamer(fn func(dirs []string, old, new string) error) Option {
+	return func(d *Tree) { d.renameFn = fn }
 }
 
 // WithOpener overrides how entries are opened (bypasses filesystem read).
-func WithOpener(fn func(dirs []string, name string) (StoreEntry, error)) DirOption {
-	return func(d *DirStore) { d.openFn = fn }
+func WithOpener(fn func(dirs []string, name string) (File, error)) Option {
+	return func(d *Tree) { d.openFn = fn }
 }
 
 // WithStat overrides how entries are stat'd.
-func WithStat(fn func(dirs []string, name string) (os.FileInfo, error)) DirOption {
-	return func(d *DirStore) { d.statFn = fn }
+func WithStat(fn func(dirs []string, name string) (os.FileInfo, error)) Option {
+	return func(d *Tree) { d.statFn = fn }
 }
 
-// WithListDir overrides subdirectory listing.
-func WithListDir(fn func(dirs []string, name string) ([]os.DirEntry, error)) DirOption {
-	return func(d *DirStore) { d.listDirFn = fn }
+// WithReaddir overrides subdirectory listing.
+func WithReaddir(fn func(dirs []string, name string) ([]os.DirEntry, error)) Option {
+	return func(d *Tree) { d.readdirFn = fn }
 }
 
-// NewDirStore creates a DirStore backed by one or more directories.
+// NewTree creates a Tree backed by one or more directories.
 // The first directory is the write target for unions.
-func NewDirStore(dirs []string, perm os.FileMode, opts ...DirOption) *DirStore {
-	d := &DirStore{dirs: dirs, perm: perm}
+func NewTree(dirs []string, perm os.FileMode, opts ...Option) *Tree {
+	d := &Tree{Tree: dirs, perm: perm}
 	for _, o := range opts {
 		o(d)
 	}
 	return d
 }
 
-// Mount attaches a child DirStore at the given name.
-func (d *DirStore) Mount(name string, child *DirStore) {
+// Mount attaches a child Tree at the given name.
+func (d *Tree) Mount(name string, child *Tree) {
 	if d.children == nil {
-		d.children = make(map[string]*DirStore)
+		d.children = make(map[string]*Tree)
 	}
 	d.children[name] = child
 }
 
 // Unmount removes a mounted child.
-func (d *DirStore) Unmount(name string) {
+func (d *Tree) Unmount(name string) {
 	delete(d.children, name)
 }
 
 // Child returns the child mounted at name, or nil.
-func (d *DirStore) Child(name string) *DirStore {
+func (d *Tree) Child(name string) *Tree {
 	if d.children == nil {
 		return nil
 	}
@@ -112,7 +112,7 @@ func (d *DirStore) Child(name string) *DirStore {
 
 // split checks if name routes to a child store. Returns (child, rest, true)
 // if a child handles this path, or (nil, "", false) otherwise.
-func (d *DirStore) split(name string) (*DirStore, string, bool) {
+func (d *Tree) split(name string) (*Tree, string, bool) {
 	if d.children == nil {
 		return nil, "", false
 	}
@@ -139,11 +139,11 @@ func indexOf(s string, b byte) int {
 	return -1
 }
 
-func (d *DirStore) resolve(name string) (string, error) {
+func (d *Tree) resolve(name string) (string, error) {
 	if d.resolveFn != nil {
-		return d.resolveFn(d.dirs, name)
+		return d.resolveFn(d.Tree, name)
 	}
-	for _, dir := range d.dirs {
+	for _, dir := range d.Tree {
 		p := filepath.Join(dir, name)
 		if _, err := os.Stat(p); err == nil {
 			return p, nil
@@ -152,11 +152,11 @@ func (d *DirStore) resolve(name string) (string, error) {
 	return "", fmt.Errorf("%s: not found", name)
 }
 
-func (d *DirStore) writePath(name string) string {
-	return filepath.Join(d.dirs[0], name)
+func (d *Tree) writePath(name string) string {
+	return filepath.Join(d.Tree[0], name)
 }
 
-func (d *DirStore) Stat(name string) (os.FileInfo, error) {
+func (d *Tree) Stat(name string) (os.FileInfo, error) {
 	// Check children first.
 	if child, rest, ok := d.split(name); ok {
 		if rest == "" {
@@ -169,11 +169,11 @@ func (d *DirStore) Stat(name string) (os.FileInfo, error) {
 	}
 	// Custom stat hook.
 	if d.statFn != nil {
-		return d.statFn(d.dirs, name)
+		return d.statFn(d.Tree, name)
 	}
 	// Synthetic files: use opener for stat.
 	if d.openFn != nil {
-		e, err := d.openFn(d.dirs, name)
+		e, err := d.openFn(d.Tree, name)
 		if err != nil {
 			return nil, err
 		}
@@ -193,9 +193,9 @@ func (d *DirStore) Stat(name string) (os.FileInfo, error) {
 	return info, nil
 }
 
-func (d *DirStore) List() ([]os.DirEntry, error) {
+func (d *Tree) List() ([]os.DirEntry, error) {
 	if d.listFn != nil {
-		entries, err := d.listFn(d.dirs)
+		entries, err := d.listFn(d.Tree)
 		if err != nil {
 			return nil, err
 		}
@@ -216,7 +216,7 @@ func (d *DirStore) List() ([]os.DirEntry, error) {
 		result = append(result, FileEntry("idx", 0444))
 		seen["idx"] = true
 	}
-	for _, dir := range d.dirs {
+	for _, dir := range d.Tree {
 		entries, err := os.ReadDir(dir)
 		if err != nil {
 			continue
@@ -236,7 +236,7 @@ func (d *DirStore) List() ([]os.DirEntry, error) {
 	return result, nil
 }
 
-func (d *DirStore) Open(name string) (StoreEntry, error) {
+func (d *Tree) Open(name string) (File, error) {
 	// Delegate to child stores.
 	if child, rest, ok := d.split(name); ok {
 		if rest == "" {
@@ -248,7 +248,7 @@ func (d *DirStore) Open(name string) (StoreEntry, error) {
 		return nil, "", fmt.Errorf("blocking read not supported")
 	}
 	if name == "idx" && d.indexFn != nil {
-		return &EntryConfig{
+		return &FileConfig{
 			StatFn:         func() (os.FileInfo, error) { return &SyntheticFileInfo{Name_: "idx", Mode_: 0444}, nil },
 			ReadFn:         func() ([]byte, error) { return d.indexFn(d) },
 			WriteFn:        func([]byte) error { return fmt.Errorf("idx: read-only") },
@@ -256,7 +256,7 @@ func (d *DirStore) Open(name string) (StoreEntry, error) {
 		}, nil
 	}
 	if d.openFn != nil {
-		return d.openFn(d.dirs, name)
+		return d.openFn(d.Tree, name)
 	}
 	p, err := d.resolve(name)
 	if err != nil {
@@ -276,7 +276,7 @@ func (d *DirStore) Open(name string) (StoreEntry, error) {
 		}
 		return os.WriteFile(wp, data, d.perm)
 	}
-	return &EntryConfig{
+	return &FileConfig{
 		StatFn:         func() (os.FileInfo, error) { return os.Stat(p) },
 		ReadFn:         func() ([]byte, error) { return os.ReadFile(p) },
 		WriteFn:        writeFn,
@@ -284,7 +284,7 @@ func (d *DirStore) Open(name string) (StoreEntry, error) {
 	}, nil
 }
 
-func (d *DirStore) Create(name string) error {
+func (d *Tree) Create(name string) error {
 	if child, rest, ok := d.split(name); ok && rest != "" {
 		return child.Create(rest)
 	}
@@ -292,7 +292,7 @@ func (d *DirStore) Create(name string) error {
 		return fmt.Errorf("read-only store")
 	}
 	if d.createFn != nil {
-		return d.createFn(d.dirs, name, d.perm)
+		return d.createFn(d.Tree, name, d.perm)
 	}
 	p := d.writePath(name)
 	if err := os.MkdirAll(filepath.Dir(p), 0755); err != nil {
@@ -301,7 +301,7 @@ func (d *DirStore) Create(name string) error {
 	return os.WriteFile(p, nil, d.perm)
 }
 
-func (d *DirStore) Delete(name string) error {
+func (d *Tree) Delete(name string) error {
 	if child, rest, ok := d.split(name); ok && rest != "" {
 		return child.Delete(rest)
 	}
@@ -309,7 +309,7 @@ func (d *DirStore) Delete(name string) error {
 		return fmt.Errorf("read-only store")
 	}
 	if d.deleteFn != nil {
-		return d.deleteFn(d.dirs, name)
+		return d.deleteFn(d.Tree, name)
 	}
 	p, err := d.resolve(name)
 	if err != nil {
@@ -318,7 +318,7 @@ func (d *DirStore) Delete(name string) error {
 	return os.Remove(p)
 }
 
-func (d *DirStore) Rename(old, new string) error {
+func (d *Tree) Rename(old, new string) error {
 	if child, rest, ok := d.split(old); ok && rest != "" {
 		return child.Rename(rest, new)
 	}
@@ -326,7 +326,7 @@ func (d *DirStore) Rename(old, new string) error {
 		return fmt.Errorf("read-only store")
 	}
 	if d.renameFn != nil {
-		return d.renameFn(d.dirs, old, new)
+		return d.renameFn(d.Tree, old, new)
 	}
 	p, err := d.resolve(old)
 	if err != nil {
@@ -335,34 +335,34 @@ func (d *DirStore) Rename(old, new string) error {
 	return os.Rename(p, filepath.Join(filepath.Dir(p), new))
 }
 
-// ListDir lists entries in a subdirectory.
-func (d *DirStore) ListDir(rel string) ([]os.DirEntry, error) {
+// Readdir lists entries in a subdirectory.
+func (d *Tree) Readdir(rel string) ([]os.DirEntry, error) {
 	// Check if rel routes to a child.
 	if child, rest, ok := d.split(rel); ok {
 		if rest == "" {
 			return child.List()
 		}
-		return child.ListDir(rest)
+		return child.Readdir(rest)
 	}
-	if d.listDirFn != nil {
-		return d.listDirFn(d.dirs, rel)
+	if d.readdirFn != nil {
+		return d.readdirFn(d.Tree, rel)
 	}
-	if len(d.dirs) == 0 {
+	if len(d.Tree) == 0 {
 		return nil, fmt.Errorf("%s: not found", rel)
 	}
-	return os.ReadDir(filepath.Join(d.dirs[0], rel))
+	return os.ReadDir(filepath.Join(d.Tree[0], rel))
 }
 
 // MkdirAll creates a directory relative to the first backing dir.
-func (d *DirStore) MkdirAll(rel string) error {
+func (d *Tree) MkdirAll(rel string) error {
 	if child, rest, ok := d.split(rel); ok && rest != "" {
 		return child.MkdirAll(rest)
 	}
 	if d.readOnly {
 		return fmt.Errorf("read-only store")
 	}
-	if len(d.dirs) == 0 {
+	if len(d.Tree) == 0 {
 		return fmt.Errorf("no backing directory")
 	}
-	return os.MkdirAll(filepath.Join(d.dirs[0], rel), 0755)
-}
+	return os.MkdirAll(filepath.Join(d.Tree[0], rel), 0755)
+}
\ No newline at end of file
diff --git a/main_test.go b/main_test.go
index 4a40782..74d9661 100644
--- a/main_test.go
+++ b/main_test.go
@@ -14,7 +14,7 @@ import (
 	"ollie/pkg/backend"
 	olog "ollie/pkg/log"
 	"olliesrv/session"
-	"olliesrv/store"
+	"olliesrv/fs"
 )
 
 // --- stub agent.Core ---
@@ -137,7 +137,7 @@ func newTestSessionManagerWithCore(t *testing.T) *session.Manager {
 	})
 }
 
-func testStoreRead(t *testing.T, s store.Store, name string) []byte {
+func testStoreRead(t *testing.T, s fs.FileTree, name string) []byte {
 	t.Helper()
 	e, err := s.Open(name)
 	if err != nil { t.Fatalf("Open(%s): %v", name, err) }
@@ -146,7 +146,7 @@ func testStoreRead(t *testing.T, s store.Store, name string) []byte {
 	return data
 }
 
-func testStoreWrite(t *testing.T, s store.Store, name string, data []byte) {
+func testStoreWrite(t *testing.T, s fs.FileTree, name string, data []byte) {
 	t.Helper()
 	e, err := s.Open(name)
 	if err != nil { t.Fatalf("Open(%s): %v", name, err) }
@@ -162,7 +162,7 @@ func newTestSessionFileStore(t *testing.T, sess *session.Session) (*session.File
 	t.Helper()
 	sink := testSink()
 	core := sess.Core.(*stubCore)
-	sf := session.NewFileStore(sess, sink.NewLogger("test"),
+	sf := session.NewSynth(sess, sink.NewLogger("test"),
 		func() {},
 		func(id string) error { return nil },
 		func(data []byte) error { return nil },
@@ -173,7 +173,7 @@ func newTestSessionFileStore(t *testing.T, sess *session.Session) (*session.File
 func newTestSessionFileStoreWith(t *testing.T, sess *session.Session, kill func(), rename func(string) error, save func([]byte) error) *session.FileStore {
 	t.Helper()
 	sink := testSink()
-	return session.NewFileStore(sess, sink.NewLogger("test"), kill, rename, save)
+	return session.NewSynth(sess, sink.NewLogger("test"), kill, rename, save)
 }
 // ===== session.Session =====
 
@@ -395,7 +395,7 @@ func TestSessionFileStoreReadableContract(t *testing.T) {
 	sess := testSession("s1")
 	defer sess.Cancel()
 	sink := testSink()
-	_ = session.NewFileStore(sess, sink.NewLogger("test"),
+	_ = session.NewSynth(sess, sink.NewLogger("test"),
 		func() {}, func(string) error { return nil }, func([]byte) error { return nil })
 }
 
@@ -403,7 +403,7 @@ func TestSessionFileStoreList(t *testing.T) {
 	sess := testSession("s1")
 	defer sess.Cancel()
 	sink := testSink()
-	sf := session.NewFileStore(sess, sink.NewLogger("test"),
+	sf := session.NewSynth(sess, sink.NewLogger("test"),
 		func() {}, func(string) error { return nil }, func([]byte) error { return nil })
 
 	entries, err := sf.List()
@@ -420,7 +420,7 @@ func TestSessionFileStoreStatChat(t *testing.T) {
 	defer sess.Cancel()
 	sess.AppendLog([]byte("hello"))
 	sink := testSink()
-	sf := session.NewFileStore(sess, sink.NewLogger("test"),
+	sf := session.NewSynth(sess, sink.NewLogger("test"),
 		func() {}, func(string) error { return nil }, func([]byte) error { return nil })
 
 	fi, err := sf.Stat("chat")
@@ -437,7 +437,7 @@ func TestSessionFileStoreGetChat(t *testing.T) {
 	defer sess.Cancel()
 	sess.AppendLog([]byte("hello"))
 	sink := testSink()
-	sf := session.NewFileStore(sess, sink.NewLogger("test"),
+	sf := session.NewSynth(sess, sink.NewLogger("test"),
 		func() {}, func(string) error { return nil }, func([]byte) error { return nil })
 
 	data := testStoreRead(t, sf, "chat")
@@ -450,7 +450,7 @@ func TestSessionFileStoreGetContent(t *testing.T) {
 	sess := testSession("s1")
 	defer sess.Cancel()
 	sink := testSink()
-	sf := session.NewFileStore(sess, sink.NewLogger("test"),
+	sf := session.NewSynth(sess, sink.NewLogger("test"),
 		func() {}, func(string) error { return nil }, func([]byte) error { return nil })
 
 	for _, name := range []string{"cfg", "offset", "usage", "ctxsz", "models", "systemprompt"} {
@@ -464,7 +464,7 @@ func TestSessionFileStorePutCwd(t *testing.T) {
 	sess := testSession("s1")
 	defer sess.Cancel()
 	sink := testSink()
-	sf := session.NewFileStore(sess, sink.NewLogger("test"),
+	sf := session.NewSynth(sess, sink.NewLogger("test"),
 		func() {}, func(string) error { return nil }, func([]byte) error { return nil })
 
 	testStoreWrite(t, sf, "cfg", []byte("cwd=/new/path"))
@@ -478,7 +478,7 @@ func TestSessionFileStorePutEmpty(t *testing.T) {
 	sess := testSession("s1")
 	defer sess.Cancel()
 	sink := testSink()
-	sf := session.NewFileStore(sess, sink.NewLogger("test"),
+	sf := session.NewSynth(sess, sink.NewLogger("test"),
 		func() {}, func(string) error { return nil }, func([]byte) error { return nil })
 
 	// Empty write is a no-op
@@ -985,7 +985,7 @@ func TestFormatEvent(t *testing.T) {
 // ===== SyntheticFileInfo / SyntheticEntry / FileEntry / DirEntry =====
 
 func TestSyntheticFileInfo(t *testing.T) {
-	fi := &store.SyntheticFileInfo{Name_: "f", Mode_: 0644, Size_: 42, IsDir_: false}
+	fi := &fs.SyntheticFileInfo{Name_: "f", Mode_: 0644, Size_: 42, IsDir_: false}
 	if fi.Name() != "f" || fi.Size() != 42 || fi.Mode() != 0644 || fi.IsDir() || fi.Sys() != nil {
 		t.Error("SyntheticFileInfo field mismatch")
 	}
@@ -995,11 +995,11 @@ func TestSyntheticFileInfo(t *testing.T) {
 }
 
 func TestFileEntryDirEntry(t *testing.T) {
-	fe := store.FileEntry("f", 0644)
+	fe := fs.FileEntry("f", 0644)
 	if fe.Name() != "f" || fe.IsDir() || fe.Type() != 0 {
 		t.Error("FileEntry mismatch")
 	}
-	de := store.DirEntry("d", 0755)
+	de := fs.DirEntry("d", 0755)
 	if de.Name() != "d" || !de.IsDir() || de.Type() != os.ModeDir {
 		t.Error("DirEntry mismatch")
 	}
diff --git a/server/server.go b/server/server.go
index 5dbbd7a..f8ec12c 100644
--- a/server/server.go
+++ b/server/server.go
@@ -20,17 +20,17 @@ import (
 	"ollie/pkg/paths"
 	"ollie/pkg/tools/execute"
 	"olliesrv/session"
-	"olliesrv/store"
+	"olliesrv/fs"
 
 	"9fans.net/go/plan9"
 )
 
 // Re-export store types for use in server.go.
 type (
-	StoreEntry = store.StoreEntry
-	Store      = store.Store
+	File = fs.File
+	FileTree      = fs.FileTree
 
-	syntheticFileInfo = store.SyntheticFileInfo
+	syntheticFileInfo = fs.SyntheticFileInfo
 )
 
 const (
@@ -64,17 +64,17 @@ type Server struct {
 	log             *olog.Logger
 	sink            *olog.Sink
 	agentsDir       string // kept for session creation wiring
-	agentStore      Store
-	promptStore     Store
-	memStore        Store
-	toolStore       *store.DirStore
-	utilStore       Store
-	pluginStore     Store
-	skillStore      Store
+	agentStore      FileTree
+	promptStore     FileTree
+	memStore        FileTree
+	toolStore       *fs.Tree
+	utilStore       FileTree
+	pluginStore     FileTree
+	skillStore      FileTree
 	sessionMgr    *session.Manager
-	transcriptStore Store
-	tmpStore        Store
-	rootStore       *store.DirStore
+	transcriptStore FileTree
+	tmpStore        FileTree
+	rootStore       *fs.Tree
 	strict          bool
 	yolo            bool
 	groups          map[string]map[string]bool // group → set of members
@@ -101,16 +101,16 @@ func New(sink *olog.Sink, opts ...Option) *Server {
 		log:             sink.Logger("9p", olog.LevelDebug),
 		sink:            sink,
 		agentsDir:       agentsDir,
-		agentStore:      store.NewDirStore(agentsDirs, 0644),
-		promptStore:     store.NewDirStore(agent.PromptsDirs(), 0444, store.WithReadOnly()),
-		memStore:        store.NewDirStore([]string{memDir}, 0644),
-		toolStore:       store.NewDirStore([]string{execute.ToolsPath()}, 0755, store.WithIndex(store.ToolIndex)),
-		utilStore:       store.NewDirStore([]string{paths.CfgDir() + "/scripts/u"}, 0555, store.WithReadOnly()),
-		pluginStore:     store.NewDirStore([]string{execute.PluginsPath()}, 0555, store.WithReadOnly()),
-		skillStore:      store.NewSkillStore(),
-		transcriptStore: store.NewDirStore([]string{transcriptDir}, 0444, store.WithReadOnly()),
-		tmpStore:        store.NewDirStore([]string{tmpDir}, 0600),
-		rootStore:       store.NewRootStore(),
+		agentStore:      fs.NewTree(agentsDirs, 0644),
+		promptStore:     fs.NewTree(agent.PromptsDirs(), 0444, fs.WithReadOnly()),
+		memStore:        fs.NewTree([]string{memDir}, 0644),
+		toolStore:       fs.NewTree([]string{execute.ToolsPath()}, 0755, fs.WithIndex(fs.ToolIndex)),
+		utilStore:       fs.NewTree([]string{paths.CfgDir() + "/scripts/u"}, 0555, fs.WithReadOnly()),
+		pluginStore:     fs.NewTree([]string{execute.PluginsPath()}, 0555, fs.WithReadOnly()),
+		skillStore:      fs.NewSkillStore(),
+		transcriptStore: fs.NewTree([]string{transcriptDir}, 0444, fs.WithReadOnly()),
+		tmpStore:        fs.NewTree([]string{tmpDir}, 0600),
+		rootStore:       fs.NewRootStore(),
 		groups:          make(map[string]map[string]bool),
 	}
 	for _, o := range opts {
@@ -151,29 +151,29 @@ func New(sink *olog.Sink, opts ...Option) *Server {
 	return s
 }
 
-// storeRoute maps a path prefix to its backing store.
+// storeRoute maps a path prefix to its backing fs.
 type storeRoute struct {
 	prefix string
-	store  func() Store
+	store  func() FileTree
 }
 
 // storeRoutes returns the route table for generic store-backed paths.
 func (s *Server) storeRoutes() []storeRoute {
 	return []storeRoute{
-		{"/a/", func() Store { return s.agentStore }},
-		{"/p/", func() Store { return s.promptStore }},
-		{"/m/", func() Store { return s.memStore }},
-		{"/s/", func() Store { return s.sessionMgr.Store() }},
-		{"/sk/", func() Store { return s.skillStore }},
-		{"/u/", func() Store { return s.utilStore }},
-		{"/x/", func() Store { return s.pluginStore }},
-		{"/tmp/", func() Store { return s.tmpStore }},
-		{"/tr/", func() Store { return s.transcriptStore }},
+		{"/a/", func() FileTree { return s.agentStore }},
+		{"/p/", func() FileTree { return s.promptStore }},
+		{"/m/", func() FileTree { return s.memStore }},
+		{"/s/", func() FileTree { return s.sessionMgr.Store() }},
+		{"/sk/", func() FileTree { return s.skillStore }},
+		{"/u/", func() FileTree { return s.utilStore }},
+		{"/x/", func() FileTree { return s.pluginStore }},
+		{"/tmp/", func() FileTree { return s.tmpStore }},
+		{"/tr/", func() FileTree { return s.transcriptStore }},
 	}
 }
 
 // routeStore returns the store and entry name for a path, or nil if no route matches.
-func (s *Server) routeStore(path string) (Store, string) {
+func (s *Server) routeStore(path string) (FileTree, string) {
 	for _, r := range s.storeRoutes() {
 		if strings.HasPrefix(path, r.prefix) {
 			return r.store(), strings.TrimPrefix(path, r.prefix)
@@ -189,8 +189,8 @@ func (s *Server) routeStore(path string) (Store, string) {
 	return nil, ""
 }
 
-// openEntry opens a StoreEntry for the given path.
-func (s *Server) openEntry(path string) (StoreEntry, error) {
+// openEntry opens a File for the given path.
+func (s *Server) openEntry(path string) (File, error) {
 	st, name := s.routeStore(path)
 	if st == nil {
 		return nil, fmt.Errorf("%s: not found", path)
@@ -199,7 +199,7 @@ func (s *Server) openEntry(path string) (StoreEntry, error) {
 }
 
 // routeDir returns the store for a directory path (e.g. "/a" → agentStore).
-func (s *Server) routeDir(path string) Store {
+func (s *Server) routeDir(path string) FileTree {
 	for _, r := range s.storeRoutes() {
 		if path+"/" == r.prefix {
 			return r.store()
@@ -328,7 +328,7 @@ func defaultTmpDir() string {
 
 
 // storeRead opens an entry in a store and reads it.
-func storeRead(s store.Store, name string) ([]byte, error) {
+func storeRead(s fs.FileTree, name string) ([]byte, error) {
 	e, err := s.Open(name)
 	if err != nil {
 		return nil, err
@@ -337,7 +337,7 @@ func storeRead(s store.Store, name string) ([]byte, error) {
 }
 
 // storeWrite opens an entry in a store and writes to it.
-func storeWrite(s store.Store, name string, data []byte) error {
+func storeWrite(s fs.FileTree, name string, data []byte) error {
 	e, err := s.Open(name)
 	if err != nil {
 		return err
@@ -665,7 +665,7 @@ func (s *Server) create(cs *connState, fc *plan9.Fcall) *plan9.Fcall {
 
 	s.log.Debug("Tcreate parent=%q name=%q", f.path, fc.Name)
 
-	// File create: route to the parent directory's store.
+	// File create: route to the parent directory's fs.
 	if st := s.routeDir(f.path); st != nil {
 		if err := st.Create(fc.Name); err != nil {
 			return errFcall(fc, err.Error())
@@ -975,10 +975,10 @@ func (s *Server) readDir(path string, offset uint64, count uint32) []byte {
 	} else if st, name := s.routeStore(path); st != nil {
 		// Subdirectory within a store (e.g. /s/mysession, /s/mysession/t).
 		type dirLister interface {
-			ListDir(string) ([]os.DirEntry, error)
+			Readdir(string) ([]os.DirEntry, error)
 		}
 		if dl, ok := st.(dirLister); ok {
-			entries, _ := dl.ListDir(name)
+			entries, _ := dl.Readdir(name)
 			for _, e := range entries {
 				fpath := path + "/" + e.Name()
 				d := s.makeStat(fpath)
@@ -1135,7 +1135,7 @@ func (s *Server) makeStat(path string) plan9.Dir {
 		}
 	}
 
-	// For memory and plan files, report real size and timestamps from the store.
+	// For memory and plan files, report real size and timestamps from the fs.
 	if strings.HasPrefix(path, "/m/") {
 		if info, err := s.memStore.Stat(base); err == nil {
 			dir.Length = uint64(info.Size())
diff --git a/session/session.go b/session/session.go
index de7adf9..521dced 100644
--- a/session/session.go
+++ b/session/session.go
@@ -16,7 +16,7 @@ import (
 	"ollie/pkg/paths"
 	"ollie/pkg/tools"
 	"ollie/pkg/tools/execute"
-	"olliesrv/store"
+	"olliesrv/fs"
 )
 
 // Session holds all state for one agent session.
@@ -113,7 +113,7 @@ type ManagerConfig struct {
 	OnRename       func(oldID, newID string)
 	SaveTranscript func([]byte) error
 	// ToolStore provides access to the shared tool directory.
-	ToolStore store.Store
+	ToolStore fs.FileTree
 	// NewCore, if non-nil, replaces the default backend.New + agent.NewAgentCore
 	// path. It receives the session ID, agent name, and cwd, and returns a Core.
 	NewCore func(sessionID, agentName, cwd string) (agent.Core, error)
@@ -123,17 +123,17 @@ type ManagerConfig struct {
 	Yolo bool
 }
 
-// Manager manages session lifecycle and exposes sessions as a DirStore.
+// Manager manages session lifecycle and exposes sessions as a Tree.
 type Manager struct {
-	store     *store.DirStore
+	store     *fs.Tree
 	cfg       ManagerConfig
 	mu        sync.RWMutex
 	sessions  map[string]*Session
 	nextUID   atomic.Uint32 // incrementing principal counter
 }
 
-// Store returns the DirStore view of the session namespace.
-func (s *Manager) Store() *store.DirStore { return s.store }
+// Store returns the Tree view of the session namespace.
+func (s *Manager) Store() *fs.Tree { return s.store }
 
 // nextUname generates the next uname atomically.
 func (s *Manager) nextUname() string {
@@ -152,19 +152,19 @@ func NewManager(cfg ManagerConfig) *Manager {
 		sessions: make(map[string]*Session),
 	}
 	ss.nextUID.Store(9999)
-	ss.store = store.NewDirStore(nil, 0,
-		store.WithStat(func(_ []string, name string) (os.FileInfo, error) { return ss.stat(name) }),
-		store.WithOpener(func(_ []string, name string) (store.StoreEntry, error) { return ss.openEntry(name) }),
-		store.WithLister(func(_ []string) ([]os.DirEntry, error) { return ss.list() }),
-		store.WithListDir(func(_ []string, name string) ([]os.DirEntry, error) { return ss.ListDir(name) }),
-		store.WithDeleter(func(_ []string, name string) error { return ss.del(name) }),
-		store.WithCreator(func(_ []string, name string, _ os.FileMode) error { return ss.create(name) }),
-		store.WithRenamer(func(_ []string, old, new string) error { return ss.renameSession(old, new) }),
+	ss.store = fs.NewTree(nil, 0,
+		fs.WithStat(func(_ []string, name string) (os.FileInfo, error) { return ss.stat(name) }),
+		fs.WithOpener(func(_ []string, name string) (fs.File, error) { return ss.openEntry(name) }),
+		fs.WithLister(func(_ []string) ([]os.DirEntry, error) { return ss.list() }),
+		fs.WithReaddir(func(_ []string, name string) ([]os.DirEntry, error) { return ss.Readdir(name) }),
+		fs.WithDeleter(func(_ []string, name string) error { return ss.del(name) }),
+		fs.WithCreator(func(_ []string, name string, _ os.FileMode) error { return ss.create(name) }),
+		fs.WithRenamer(func(_ []string, old, new string) error { return ss.renameSession(old, new) }),
 	)
 	return ss
 }
 
-// AddSession inserts a pre-built session into the store.
+// AddSession inserts a pre-built session into the fs.
 func (s *Manager) AddSession(sess *Session) {
 	s.mu.Lock()
 	s.sessions[sess.RunnableID()] = sess
@@ -174,18 +174,18 @@ func (s *Manager) AddSession(sess *Session) {
 func (s *Manager) list() ([]os.DirEntry, error) {
 	entries := make([]os.DirEntry, 0, len(sessionStoreOrder))
 	for _, name := range sessionStoreOrder {
-		entries = append(entries, store.FileEntry(name, sessionStoreFiles[name]))
+		entries = append(entries, fs.FileEntry(name, sessionStoreFiles[name]))
 	}
 	s.mu.RLock()
 	for id := range s.sessions {
-		entries = append(entries, store.DirEntry(id, 0555))
+		entries = append(entries, fs.DirEntry(id, 0555))
 	}
 	s.mu.RUnlock()
 	return entries, nil
 }
 
-// ListDir lists entries in a subdirectory (e.g. "{id}", "{id}/t", "{id}/t/{subdir}").
-func (s *Manager) ListDir(name string) ([]os.DirEntry, error) {
+// Readdir lists entries in a subdirectory (e.g. "{id}", "{id}/t", "{id}/t/{subdir}").
+func (s *Manager) Readdir(name string) ([]os.DirEntry, error) {
 	parts := strings.SplitN(name, "/", 3)
 	sessID := parts[0]
 	sess := s.Session(sessID)
@@ -202,7 +202,7 @@ func (s *Manager) ListDir(name string) ([]os.DirEntry, error) {
 		if err != nil {
 			return nil, err
 		}
-		entries = append(entries, store.DirEntry("t", 0500))
+		entries = append(entries, fs.DirEntry("t", 0500))
 		return entries, nil
 	}
 	// {id}/t — list tools (filtered by allowTools)
@@ -210,12 +210,12 @@ func (s *Manager) ListDir(name string) ([]os.DirEntry, error) {
 		if len(parts) == 2 {
 			return s.cfg.ToolStore.List()
 		}
-		// {id}/t/{subdir} — delegate to ToolStore.ListDir if available
+		// {id}/t/{subdir} — delegate to ToolStore.Readdir if available
 		type listDirer interface {
-			ListDir(string) ([]os.DirEntry, error)
+			Readdir(string) ([]os.DirEntry, error)
 		}
 		if ld, ok := s.cfg.ToolStore.(listDirer); ok {
-			return ld.ListDir(parts[2])
+			return ld.Readdir(parts[2])
 		}
 	}
 	return nil, fmt.Errorf("%s: not a directory", name)
@@ -224,7 +224,7 @@ func (s *Manager) ListDir(name string) ([]os.DirEntry, error) {
 func (s *Manager) stat(name string) (os.FileInfo, error) {
 	// Top-level fixed files (new, idx, sh, etc.)
 	if mode, ok := sessionStoreFiles[name]; ok {
-		return &store.SyntheticFileInfo{Name_: name, Mode_: mode}, nil
+		return &fs.SyntheticFileInfo{Name_: name, Mode_: mode}, nil
 	}
 	parts := strings.SplitN(name, "/", 3)
 	sessID := parts[0]
@@ -236,12 +236,12 @@ func (s *Manager) stat(name string) (os.FileInfo, error) {
 	}
 	// Session directory: {id}
 	if len(parts) == 1 {
-		return &store.SyntheticFileInfo{Name_: sessID, Mode_: 0555, IsDir_: true}, nil
+		return &fs.SyntheticFileInfo{Name_: sessID, Mode_: 0555, IsDir_: true}, nil
 	}
 	// Tools directory: {id}/t
 	if parts[1] == "t" {
 		if len(parts) == 2 {
-			return &store.SyntheticFileInfo{Name_: "t", Mode_: 0500, IsDir_: true}, nil
+			return &fs.SyntheticFileInfo{Name_: "t", Mode_: 0500, IsDir_: true}, nil
 		}
 		// Tool file: {id}/t/{rel}
 		if s.cfg.ToolStore != nil {
@@ -257,7 +257,7 @@ func (s *Manager) stat(name string) (os.FileInfo, error) {
 	return sfs.Stat(parts[1])
 }
 
-func (s *Manager) openEntry(name string) (store.StoreEntry, error) {
+func (s *Manager) openEntry(name string) (fs.File, error) {
 	notBlocking := func(context.Context, string) ([]byte, string, error) {
 		return nil, "", fmt.Errorf("blocking read not supported")
 	}
@@ -265,8 +265,8 @@ func (s *Manager) openEntry(name string) (store.StoreEntry, error) {
 	// Top-level fixed files.
 	switch name {
 	case "new":
-		return &store.EntryConfig{
-			StatFn: func() (os.FileInfo, error) { return &store.SyntheticFileInfo{Name_: "new", Mode_: 0666}, nil },
+		return &fs.FileConfig{
+			StatFn: func() (os.FileInfo, error) { return &fs.SyntheticFileInfo{Name_: "new", Mode_: 0666}, nil },
 			ReadFn: func() ([]byte, error) {
 				return []byte("name=\ncwd=\nbackend=\nmodel=\nagent=\nmaxTokens=\nmaxCompletionTokens=\ntemperature=\ntopP=\ntopK=\nminP=\ntopA=\nfrequencyPenalty=\npresencePenalty=\nrepetitionPenalty=\nreasoning=\nreasoningEffort=\nincludeReasoning=\nresponseFormat=\nstop=\nverbosity=\n"), nil
 			},
@@ -276,16 +276,16 @@ func (s *Manager) openEntry(name string) (store.StoreEntry, error) {
 			BlockingReadFn: notBlocking,
 		}, nil
 	case "idx":
-		return &store.EntryConfig{
-			StatFn:         func() (os.FileInfo, error) { return &store.SyntheticFileInfo{Name_: "idx", Mode_: 0444}, nil },
+		return &fs.FileConfig{
+			StatFn:         func() (os.FileInfo, error) { return &fs.SyntheticFileInfo{Name_: "idx", Mode_: 0444}, nil },
 			ReadFn:         func() ([]byte, error) { return s.index(), nil },
 			WriteFn:        func([]byte) error { return fmt.Errorf("idx: read-only") },
 			BlockingReadFn: notBlocking,
 		}, nil
 	}
 	if _, ok := sessionStoreFiles[name]; ok {
-		return &store.EntryConfig{
-			StatFn: func() (os.FileInfo, error) { return &store.SyntheticFileInfo{Name_: name, Mode_: sessionStoreFiles[name]}, nil },
+		return &fs.FileConfig{
+			StatFn: func() (os.FileInfo, error) { return &fs.SyntheticFileInfo{Name_: name, Mode_: sessionStoreFiles[name]}, nil },
 			ReadFn: func() ([]byte, error) {
 				return s.cfg.ReadFile(paths.CfgDir() + "/scripts/s/" + name)
 			},
@@ -332,12 +332,12 @@ func (s *Manager) openEntry(name string) (store.StoreEntry, error) {
 }
 
 
-func (s *Manager) openFilteredToolIdx(allowed map[string]bool) (store.StoreEntry, error) {
+func (s *Manager) openFilteredToolIdx(allowed map[string]bool) (fs.File, error) {
 	base, err := s.cfg.ToolStore.Open("idx")
 	if err != nil {
 		return nil, err
 	}
-	return &store.EntryConfig{
+	return &fs.FileConfig{
 		StatFn: base.Stat,
 		ReadFn: func() ([]byte, error) {
 			data, err := base.Read()
@@ -375,7 +375,7 @@ func (s *Manager) create(name string) error {
 	return fmt.Errorf("create not supported: %s", name)
 }
 
-// MkdirAll creates a directory within the session's tool store.
+// MkdirAll creates a directory within the session's tool fs.
 func (s *Manager) MkdirAll(name string) error {
 	parts := strings.SplitN(name, "/", 3)
 	if len(parts) == 3 && parts[1] == "t" {
@@ -433,17 +433,17 @@ func (s *Manager) SessionByUname(uname string) *Session {
 	return nil
 }
 
-// OpenStore returns a DirStore for the given session ID.
-func (s *Manager) OpenStore(id string) (*store.DirStore, error) {
+// OpenStore returns a Tree for the given session ID.
+func (s *Manager) OpenStore(id string) (*fs.Tree, error) {
 	if sess := s.Session(id); sess != nil {
 		return s.openStore(sess)
 	}
 	return nil, fmt.Errorf("session not found: %s", id)
 }
 
-func (s *Manager) openStore(sess *Session) (*store.DirStore, error) {
+func (s *Manager) openStore(sess *Session) (*fs.Tree, error) {
 	id := sess.RunnableID()
-	return NewFileStore(
+	return NewSynth(
 		sess,
 		s.cfg.Log,
 		func() { s.KillSession(id) },
diff --git a/session/sessionfile.go b/session/sessionfile.go
index ba2c12e..454f608 100644
--- a/session/sessionfile.go
+++ b/session/sessionfile.go
@@ -11,7 +11,7 @@ import (
 	"ollie/pkg/agent"
 	"ollie/pkg/backend"
 	olog "ollie/pkg/log"
-	"olliesrv/store"
+	"olliesrv/fs"
 )
 
 // FileList defines the fixed set of files in a session directory.
@@ -42,18 +42,18 @@ var FileList = []struct {
 	{"context", 0444, false, false},
 }
 
-// FileStore is a DirStore for a session directory.
-type FileStore = store.DirStore
+// FileStore is a Tree for a session directory.
+type FileStore = fs.Tree
 
-func NewFileStore(sess *Session, log *olog.Logger, kill func(), rename func(newID string) error, saveTranscript func([]byte) error) *FileStore {
+func NewSynth(sess *Session, log *olog.Logger, kill func(), rename func(newID string) error, saveTranscript func([]byte) error) *FileStore {
 	h := &sessionHelper{sess: sess, log: log, kill: kill, rename: rename, saveTranscript: saveTranscript}
-	specs := make([]store.FileSpec, len(FileList))
+	specs := make([]fs.FileSpec, len(FileList))
 	for i, f := range FileList {
 		specs[i] = h.fileSpec(f.Name, f.Mode)
 		specs[i].OneShot = f.OneShot
 		specs[i].Async = f.Async
 	}
-	return store.NewFileStore(specs)
+	return fs.NewSynth(specs)
 }
 
 // sessionHelper holds the dependencies needed to build session FileSpecs.
@@ -65,8 +65,8 @@ type sessionHelper struct {
 	saveTranscript func([]byte) error
 }
 
-func (h *sessionHelper) fileSpec(name string, mode os.FileMode) store.FileSpec {
-	fs := store.FileSpec{Name: name, Mode: mode}
+func (h *sessionHelper) fileSpec(name string, mode os.FileMode) fs.FileSpec {
+	fs := fs.FileSpec{Name: name, Mode: mode}
 
 	// Read
 	switch name {