diff --git a/hermes_cli/container_boot.py b/hermes_cli/container_boot.py
index 4bec8534008..ed345ecdd9e 100644
--- a/hermes_cli/container_boot.py
+++ b/hermes_cli/container_boot.py
@@ -462,7 +462,7 @@ def _register_service(scandir: Path, profile: str, *, start: bool) -> None:
         run.chmod(0o755)
 
         finish = tmp_dir / "finish"
-        finish.write_text(S6ServiceManager._render_finish_script())
+        finish.write_text(S6ServiceManager._render_finish_script(), encoding="utf-8")
         finish.chmod(0o755)
 
         # Persistent log rotation (OQ8-C).
diff --git a/hermes_cli/main.py b/hermes_cli/main.py
index 46625b0633d..101617de9ad 100644
--- a/hermes_cli/main.py
+++ b/hermes_cli/main.py
@@ -4806,7 +4806,7 @@ def _gateway_prompt(prompt_text: str, default: str = "", timeout: float = 300.0)
         "id": str(_uuid.uuid4()),
     }
     tmp = prompt_path.with_suffix(".tmp")
-    tmp.write_text(_json.dumps(payload))
+    tmp.write_text(_json.dumps(payload), encoding="utf-8")
     tmp.replace(prompt_path)
 
     # Poll for response
@@ -11905,7 +11905,7 @@ def _cmd_update_impl(args, gateway_mode: bool):
         if gateway_mode:
             _exit_code_path = get_hermes_home() / ".update_exit_code"
             try:
-                _exit_code_path.write_text("0")
+                _exit_code_path.write_text("0", encoding="utf-8")
             except OSError:
                 pass
 
diff --git a/hermes_cli/profiles.py b/hermes_cli/profiles.py
index df5c5984d19..0ab0562deae 100644
--- a/hermes_cli/profiles.py
+++ b/hermes_cli/profiles.py
@@ -458,7 +458,7 @@ def create_wrapper_script(name: str, target: Optional[str] = None) -> Optional[P
     if is_windows:
         wrapper_path = wrapper_dir / f"{canon}.bat"
         try:
-            wrapper_path.write_text(f"@echo off\r\nhermes -p {profile} %*\r\n")
+            wrapper_path.write_text(f"@echo off\r\nhermes -p {profile} %*\r\n", encoding="utf-8")
             return wrapper_path
         except OSError as e:
             print(f"⚠ Could not create wrapper at {wrapper_path}: {e}")
@@ -467,7 +467,7 @@ def create_wrapper_script(name: str, target: Optional[str] = None) -> Optional[P
         wrapper_path = wrapper_dir / canon
         try:
             hermes_exe = shutil.which("hermes") or "hermes"
-            wrapper_path.write_text(f'#!/bin/sh\nexec {shlex.quote(hermes_exe)} -p {profile} "$@"\n')
+            wrapper_path.write_text(f'#!/bin/sh\nexec {shlex.quote(hermes_exe)} -p {profile} "$@"\n', encoding="utf-8")
             wrapper_path.chmod(wrapper_path.stat().st_mode | stat.S_IEXEC | stat.S_IXGRP | stat.S_IXOTH)
             return wrapper_path
         except OSError as e:
@@ -1825,7 +1825,7 @@ def set_active_profile(name: str) -> None:
     else:
         # Atomic write
         tmp = path.with_suffix(".tmp")
-        tmp.write_text(canon + "\n")
+        tmp.write_text(canon + "\n", encoding="utf-8")
         tmp.replace(path)
 
 
diff --git a/hermes_cli/service_manager.py b/hermes_cli/service_manager.py
index f213fe2e409..471c6a412cb 100644
--- a/hermes_cli/service_manager.py
+++ b/hermes_cli/service_manager.py
@@ -995,7 +995,7 @@ class S6ServiceManager:
             run_path.chmod(0o755)
 
             finish_path = tmp_dir / "finish"
-            finish_path.write_text(self._render_finish_script())
+            finish_path.write_text(self._render_finish_script(), encoding="utf-8")
             finish_path.chmod(0o755)
 
             # Persistent log rotation (OQ8-C).
diff --git a/hermes_cli/uninstall.py b/hermes_cli/uninstall.py
index c66136cc156..c02fb8cca16 100644
--- a/hermes_cli/uninstall.py
+++ b/hermes_cli/uninstall.py
@@ -87,7 +87,7 @@ def remove_path_from_shell_configs():
                 new_content = new_content.replace('\n\n\n', '\n\n')
             
             if new_content != original_content:
-                config_path.write_text(new_content)
+                config_path.write_text(new_content, encoding="utf-8")
                 removed_from.append(config_path)
                 
         except Exception as e:
diff --git a/tools/skills_hub.py b/tools/skills_hub.py
index 70e72fc5ad6..6a96e41e327 100644
--- a/tools/skills_hub.py
+++ b/tools/skills_hub.py
@@ -1154,7 +1154,7 @@ class GitHubSource(SkillSource):
         index_cache_dir.mkdir(parents=True, exist_ok=True)
         cache_file = index_cache_dir / f"{key}.json"
         try:
-            cache_file.write_text(json.dumps(data, ensure_ascii=False))
+            cache_file.write_text(json.dumps(data, ensure_ascii=False), encoding="utf-8")
         except OSError as e:
             logger.debug("Could not write cache: %s", e)
 
@@ -3370,12 +3370,12 @@ def _write_index_cache(key: str, data: Any) -> None:
     ignore_file = _hub_dir() / ".ignore"
     if not ignore_file.exists():
         try:
-            ignore_file.write_text("# Exclude hub internals from search tools\n*\n")
+            ignore_file.write_text("# Exclude hub internals from search tools\n*\n", encoding="utf-8")
         except OSError:
             pass
     cache_file = index_cache_dir / f"{key}.json"
     try:
-        cache_file.write_text(json.dumps(data, ensure_ascii=False, default=str))
+        cache_file.write_text(json.dumps(data, ensure_ascii=False, default=str), encoding="utf-8")
     except OSError as e:
         logger.debug("Could not write cache: %s", e)
 
@@ -3415,7 +3415,7 @@ class HubLockFile:
 
     def save(self, data: dict) -> None:
         self.path.parent.mkdir(parents=True, exist_ok=True)
-        self.path.write_text(json.dumps(data, indent=2, ensure_ascii=False) + "\n")
+        self.path.write_text(json.dumps(data, indent=2, ensure_ascii=False) + "\n", encoding="utf-8")
 
     def record_install(
         self,
@@ -3490,7 +3490,7 @@ class TapsManager:
 
     def save(self, taps: List[dict]) -> None:
         self.path.parent.mkdir(parents=True, exist_ok=True)
-        self.path.write_text(json.dumps({"taps": taps}, indent=2) + "\n")
+        self.path.write_text(json.dumps({"taps": taps}, indent=2) + "\n", encoding="utf-8")
 
     def add(self, repo: str, path: str = "skills/") -> bool:
         """Add a tap. Returns False if already exists."""
@@ -3549,11 +3549,11 @@ def ensure_hub_dirs() -> None:
     _quarantine_dir().mkdir(exist_ok=True)
     _index_cache_dir().mkdir(exist_ok=True)
     if not lock_file.exists():
-        lock_file.write_text('{"version": 1, "installed": {}}\n')
+        lock_file.write_text('{"version": 1, "installed": {}}\n', encoding="utf-8")
     if not audit_log.exists():
         audit_log.touch()
     if not taps_file.exists():
-        taps_file.write_text('{"taps": []}\n')
+        taps_file.write_text('{"taps": []}\n', encoding="utf-8")
 
 
 def quarantine_bundle(bundle: SkillBundle) -> Path:
@@ -3857,7 +3857,7 @@ def _load_hermes_index() -> Optional[dict]:
     # Cache locally
     try:
         hermes_index_cache_file.parent.mkdir(parents=True, exist_ok=True)
-        hermes_index_cache_file.write_text(json.dumps(data))
+        hermes_index_cache_file.write_text(json.dumps(data), encoding="utf-8")
     except OSError:
         pass
 
diff --git a/tools/web_tools.py b/tools/web_tools.py
index 7754c386a56..131c0030365 100644
--- a/tools/web_tools.py
+++ b/tools/web_tools.py
@@ -422,7 +422,7 @@ def _web_requires_env() -> list[str]:
 DEFAULT_EXTRACT_CHAR_LIMIT = 15000
 
 # Hard ceiling on the full-text file written to cache/web. The truncate-store
-# path otherwise calls path.write_text(content) with no upper bound, so a
+# path otherwise calls path.write_text(content, encoding="utf-8") with no upper bound, so a
 # multi-MB page (some backends return very large markdown) writes unbounded
 # bytes to disk on every extract. Cap the stored copy; the model only ever
 # sees char_limit anyway, and a 2MB page is already far more than any single
diff --git a/tools/xai_http.py b/tools/xai_http.py
index 8d80ae1bbd4..af820a0baf2 100644
--- a/tools/xai_http.py
+++ b/tools/xai_http.py
@@ -234,7 +234,7 @@ def maybe_mark_xai_storage_notice_seen(section_name: str) -> Optional[str]:
         marker = marker_dir / f"{section_name}_xai_storage_notice_seen"
         if marker.exists():
             return None
-        marker.write_text(datetime.datetime.now(datetime.UTC).isoformat() + "\n")
+        marker.write_text(datetime.datetime.now(datetime.UTC).isoformat() + "\n", encoding="utf-8")
         return notice
     except Exception:
         return notice