diff --git a/cmd/dotagents/hooks.go b/cmd/dotagents/hooks.go
index 5064734..180a705 100644
--- a/cmd/dotagents/hooks.go
+++ b/cmd/dotagents/hooks.go
@@ -304,7 +304,7 @@ func managedMemoryNativeCommands(home string, root string, cfgs ...config) []str
 		}
 	}
 	for _, commandRoot := range []string{root, filepath.Join(home, ".agents")} {
-		for _, script := range []string{"basic-session-start.py", "basic-session-end.py", "session-start.sh", "stop.sh", "session-end.sh"} {
+		for _, script := range []string{"basic-session-start.py", "basic-session-end.py", "session-start.sh", "stop.sh", "session-end.sh", "sync-vault-to-memory.sh", "sync-memory-to-vault.sh"} {
 			add(managedMemoryHookCommand(commandRoot, home, script))
 		}
 	}
diff --git a/cmd/dotagents/hooks_test.go b/cmd/dotagents/hooks_test.go
index 1919945..1fb7b17 100644
--- a/cmd/dotagents/hooks_test.go
+++ b/cmd/dotagents/hooks_test.go
@@ -294,8 +294,11 @@ func TestRemoveNativeManagedMemoryHooksCleansSupportedNativeConfigs(t *testing.T
   }
 }`,
 		filepath.Join(home, ".hermes", "config.yaml"): `hooks:
+  on_session_start:
+    - command: ~/.agents/memory/hooks/sync-vault-to-memory.sh
   on_session_finalize:
     - command: ~/.agents/memory/hooks/session-end.sh
+    - command: ~/.agents/memory/hooks/sync-memory-to-vault.sh
     - command: echo hermes
 `,
 	}
diff --git a/cmd/dotagents/setup_scaffold.go b/cmd/dotagents/setup_scaffold.go
index 54e9621..1e3ccaf 100644
--- a/cmd/dotagents/setup_scaffold.go
+++ b/cmd/dotagents/setup_scaffold.go
@@ -23,9 +23,11 @@ const (
 )
 
 var managedMemoryHookNames = map[string]struct{}{
-	"memory-session-start": {},
-	"memory-stop":          {},
-	"memory-session-end":   {},
+	"memory-session-start":          {},
+	"memory-stop":                   {},
+	"memory-session-end":            {},
+	"memory-hermes-vault-to-memory": {},
+	"memory-hermes-memory-to-vault": {},
 }
 
 type setupIO struct {
@@ -229,6 +231,7 @@ func applyMemoryTier(cfg *config, tier string, root string, home string) error {
 	startTargets := memoryHookAgents(*cfg, "SessionStart")
 	stopTargets := memoryHookAgents(*cfg, "Stop")
 	endTargets := memoryHookAgents(*cfg, "SessionEnd")
+	hermesTargets := enabledAgentNames(*cfg, agentHermes)
 	switch tier {
 	case memoryTierOff:
 		removeManagedMemoryHooks(cfg)
@@ -250,8 +253,11 @@ func applyMemoryTier(cfg *config, tier string, root string, home string) error {
 			return fmt.Errorf("configure memsearch: %w", err)
 		}
 		removeManagedMemoryHooks(cfg)
-		if len(startTargets) > 0 {
-			cfg.Hooks = append(cfg.Hooks, hookConfig{Name: "memory-session-start", Enabled: true, Event: "SessionStart", Command: managedMemoryHookCommand(root, home, "session-start.sh"), Timeout: 15, Agents: startTargets})
+		// session-start.sh delegates to the Claude memsearch plugin, whose
+		// hookSpecificOutput response is not consumed by Hermes. Hermes imports
+		// the shared vault into its built-in memory instead.
+		if targets := withoutAgent(startTargets, agentHermes); len(targets) > 0 {
+			cfg.Hooks = append(cfg.Hooks, hookConfig{Name: "memory-session-start", Enabled: true, Event: "SessionStart", Command: managedMemoryHookCommand(root, home, "session-start.sh"), Timeout: 15, Agents: targets})
 		}
 		if len(stopTargets) > 0 {
 			cfg.Hooks = append(cfg.Hooks, hookConfig{Name: "memory-stop", Enabled: true, Event: "Stop", Command: managedMemoryHookCommand(root, home, "stop.sh"), Timeout: 15, Agents: stopTargets})
@@ -259,6 +265,12 @@ func applyMemoryTier(cfg *config, tier string, root string, home string) error {
 		if len(endTargets) > 0 {
 			cfg.Hooks = append(cfg.Hooks, hookConfig{Name: "memory-session-end", Enabled: true, Event: "SessionEnd", Command: managedMemoryHookCommand(root, home, "session-end.sh"), Timeout: 30, Agents: endTargets})
 		}
+		if len(hermesTargets) > 0 {
+			cfg.Hooks = append(cfg.Hooks,
+				hookConfig{Name: "memory-hermes-vault-to-memory", Enabled: true, Event: "SessionStart", Command: managedMemoryHookCommand(root, home, "sync-vault-to-memory.sh"), Timeout: 30, Agents: hermesTargets},
+				hookConfig{Name: "memory-hermes-memory-to-vault", Enabled: true, Event: "SessionEnd", Command: managedMemoryHookCommand(root, home, "sync-memory-to-vault.sh"), Timeout: 30, Agents: hermesTargets},
+			)
+		}
 		return nil
 	default:
 		return fmt.Errorf("unknown memory tier %q (want off, basic, or memsearch)", tier)
@@ -293,6 +305,27 @@ func memoryHookAgents(cfg config, event string) []string {
 	return agents
 }
 
+func enabledAgentNames(cfg config, name string) []string {
+	var names []string
+	for _, agent := range cfg.Agents {
+		if agent.Enabled && normalizeAgentName(agent.Name) == name {
+			names = append(names, agent.Name)
+		}
+	}
+	sort.Strings(names)
+	return names
+}
+
+func withoutAgent(agents []string, excluded string) []string {
+	filtered := make([]string, 0, len(agents))
+	for _, agent := range agents {
+		if normalizeAgentName(agent) != excluded {
+			filtered = append(filtered, agent)
+		}
+	}
+	return filtered
+}
+
 func normalizeMemoryTier(tier string) string {
 	trimmed := strings.ToLower(strings.TrimSpace(tier))
 	if trimmed == "" {
diff --git a/cmd/dotagents/setup_separation_test.go b/cmd/dotagents/setup_separation_test.go
index 145b731..6a754d7 100644
--- a/cmd/dotagents/setup_separation_test.go
+++ b/cmd/dotagents/setup_separation_test.go
@@ -174,7 +174,7 @@ func TestMemoryTierDefinitionsAndMemsearchDependency(t *testing.T) {
 	if err := applyMemoryTier(&cfg, memoryTierMemsearch, root, home); err != nil {
 		t.Fatal(err)
 	}
-	if len(cfg.Hooks) != 4 || cfg.Hooks[1].Command != "~/.agents/memory/hooks/session-start.sh" || !stringSlicesEqual(cfg.Hooks[1].Agents, []string{agentClaudeCode, agentCodex, agentDroid, agentHermes}) || cfg.Hooks[2].Command != "~/.agents/memory/hooks/stop.sh" || !stringSlicesEqual(cfg.Hooks[2].Agents, []string{agentClaudeCode, agentCodex, agentDroid}) || cfg.Hooks[3].Command != "~/.agents/memory/hooks/session-end.sh" || !stringSlicesEqual(cfg.Hooks[3].Agents, []string{agentClaudeCode, agentCodex, agentDroid, agentHermes}) {
+	if len(cfg.Hooks) != 6 || cfg.Hooks[1].Command != "~/.agents/memory/hooks/session-start.sh" || !stringSlicesEqual(cfg.Hooks[1].Agents, []string{agentClaudeCode, agentCodex, agentDroid}) || cfg.Hooks[2].Command != "~/.agents/memory/hooks/stop.sh" || !stringSlicesEqual(cfg.Hooks[2].Agents, []string{agentClaudeCode, agentCodex, agentDroid}) || cfg.Hooks[3].Command != "~/.agents/memory/hooks/session-end.sh" || !stringSlicesEqual(cfg.Hooks[3].Agents, []string{agentClaudeCode, agentCodex, agentDroid, agentHermes}) || cfg.Hooks[4].Name != "memory-hermes-vault-to-memory" || cfg.Hooks[4].Command != "~/.agents/memory/hooks/sync-vault-to-memory.sh" || !stringSlicesEqual(cfg.Hooks[4].Agents, []string{agentHermes}) || cfg.Hooks[5].Name != "memory-hermes-memory-to-vault" || cfg.Hooks[5].Command != "~/.agents/memory/hooks/sync-memory-to-vault.sh" || !stringSlicesEqual(cfg.Hooks[5].Agents, []string{agentHermes}) {
 		t.Fatalf("memsearch hooks = %#v", cfg.Hooks)
 	}
 }
diff --git a/docs/memory.md b/docs/memory.md
index 8e1486c..b7e3121 100644
--- a/docs/memory.md
+++ b/docs/memory.md
@@ -12,6 +12,13 @@ Pick during `setup` (`--memory off|basic|memsearch`):
 | `basic` | appends a bounded digest of each session to `$KNOWLEDGE_DIR/sessions/YYYY-MM-DD.md` and injects recent digests as context at session start | Python 3 |
 | `memsearch` | full-text indexed search over the knowledge vault | `memsearch` on PATH (`uv tool install memsearch`) |
 
+On Hermes, the `memsearch` tier bridges all three stores rather than replacing
+Hermes memory: the vault is imported into `~/.hermes/memories/` at session
+start, the finalized session is captured into the vault, and Hermes durable
+memory is exported back to the vault at finalize. Hermes continues to use its
+built-in memory injector and memory tool; memsearch provides the larger indexed
+history. Run `dotagents doctor --e2e` and `hermes hooks doctor` after setup.
+
 Memory data lives in your knowledge directory (default `~/Workspace/knowledge`, configurable via `KNOWLEDGE_DIR`), never in the tool repository.
 
 ## Tools
diff --git a/memory/lib/sync.py b/memory/lib/sync.py
index 48915e0..1af73e8 100755
--- a/memory/lib/sync.py
+++ b/memory/lib/sync.py
@@ -223,13 +223,14 @@ def rendered_size(entries: list[str]) -> int:
             else:
                 break
 
-        hermes_user_path.write_text(
-            "\n§\n".join(lines) + "\n",
-            encoding="utf-8",
-        )
         added = len(lines) - len(existing_entries)
+        if added:
+            hermes_user_path.write_text(
+                "\n§\n".join(lines) + "\n",
+                encoding="utf-8",
+            )
         print(f"vault->memory: added {added} facts to {hermes_user_path} ({current_size}/{HERMES_USER_LIMIT} chars)")
-        changed = True
+        changed = added > 0
     else:
         print(f"vault->memory: {hermes_user_path} up to date")
 
diff --git a/memory/tests/test_sync.py b/memory/tests/test_sync.py
new file mode 100644
index 0000000..d861913
--- /dev/null
+++ b/memory/tests/test_sync.py
@@ -0,0 +1,42 @@
+import importlib.util
+import tempfile
+import unittest
+from pathlib import Path
+
+
+SYNC_PATH = Path(__file__).parents[1] / "lib" / "sync.py"
+SPEC = importlib.util.spec_from_file_location("dotagents_memory_sync", SYNC_PATH)
+assert SPEC is not None
+SYNC = importlib.util.module_from_spec(SPEC)
+assert SPEC.loader is not None
+SPEC.loader.exec_module(SYNC)
+
+
+class VaultToMemoryTests(unittest.TestCase):
+    def test_full_user_memory_is_not_rewritten_or_reported_changed(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            root = Path(tmp)
+            hermes_user = root / "hermes" / "USER.md"
+            vault_profile = root / "vault" / "profile" / "USER.md"
+            hermes_user.parent.mkdir(parents=True)
+            vault_profile.parent.mkdir(parents=True)
+
+            existing = "x" * (SYNC.HERMES_USER_LIMIT - 1) + "\n"
+            hermes_user.write_text(existing, encoding="utf-8")
+            vault_profile.write_text("# Profile\n\n- a distinct durable fact that cannot fit\n", encoding="utf-8")
+            before_mtime = hermes_user.stat().st_mtime_ns
+
+            changed = SYNC.vault_to_memory(
+                {
+                    "hermes_user": hermes_user,
+                    "vault_profile": vault_profile,
+                }
+            )
+
+            self.assertFalse(changed)
+            self.assertEqual(hermes_user.read_text(encoding="utf-8"), existing)
+            self.assertEqual(hermes_user.stat().st_mtime_ns, before_mtime)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/skills/dotagents/SKILL.md b/skills/dotagents/SKILL.md
index c08ae00..4a40a96 100644
--- a/skills/dotagents/SKILL.md
+++ b/skills/dotagents/SKILL.md
@@ -52,6 +52,18 @@ Memory tiers:
 - `basic` (default): Python-3-only bounded Markdown digests under `$KNOWLEDGE_DIR/sessions/` plus recent context at session start.
 - `memsearch`: the indexed SessionStart, Stop, and SessionEnd pipeline; requires `memsearch` on `PATH`.
 
+For Hermes, the `memsearch` tier also keeps the built-in memory files and the
+knowledge vault in sync: `sync-vault-to-memory.sh` runs at session start,
+`session-end.sh` captures the session digest at finalize, and
+`sync-memory-to-vault.sh` exports durable memory at finalize. The generic
+`session-start.sh` is not registered for Hermes because its Claude-style
+context response is not consumed by Hermes; Hermes injects the synchronized
+built-in memory natively instead.
+
+Verify the complete setup with `dotagents doctor --e2e`, then run
+`hermes hooks doctor`. Hermes hook approval is host-local and may require one
+interactive approval after setup.
+
 ## status
 
 Reports each configured harness as detected or not detected and compares the four managed surfaces with native state: