fix(config): write config.yaml as UTF-8 to stop emoji/personality corruption (#51676)

atomic_yaml_write (and two sibling config writers) called yaml.dump
without allow_unicode=True. The default personalities shipped in cli.py
contain emoji/kaomoji, so PyYAML escaped astral-plane chars as 8-digit
\\UXXXXXXXX sequences inside multi-line double-quoted strings wrapped
with \\ line-continuations. Stricter/non-PyYAML parsers, editors, and
hand-edits break that structure into unclosed quotes, failing the whole
config parse -> silent fallback to defaults -> custom_providers lost.

Add allow_unicode=True to the canonical writer plus tui_gateway/server.py
and the telegram adapter's atomic config write so config is written as
readable UTF-8 with no escape/fold artifacts.

Fixes #51356

plugins/platforms/telegram/adapter.py

@@ -2030,7 +2030,13 @@ class TelegramAdapter(BasePlatformAdapter):
                 )
                 try:
                     with os.fdopen(fd, "w", encoding="utf-8") as f:
-                        _yaml.dump(config, f, default_flow_style=False, sort_keys=False)
+                        _yaml.dump(
+                            config,
+                            f,
+                            default_flow_style=False,
+                            sort_keys=False,
+                            allow_unicode=True,
+                        )
                         f.flush()
                         os.fsync(f.fileno())
                     atomic_replace(tmp_path, config_path)

tests/hermes_cli/test_atomic_yaml_write.py

@@ -41,3 +41,36 @@ class TestAtomicYamlWrite:
         text = target.read_text(encoding="utf-8")
         assert "key: value" in text
         assert "# comment" in text
+
+    def test_writes_unicode_unescaped_and_round_trips(self, tmp_path):
+        """Emoji/kaomoji are written as real UTF-8, not fragile escape sequences.
+
+        Regression for GitHub #51356: without allow_unicode=True, PyYAML emitted
+        astral-plane chars (emoji) as 8-digit `\\UXXXXXXXX` escapes inside
+        multi-line double-quoted strings wrapped with `\\` continuations, which
+        stricter/non-PyYAML parsers and hand-edits broke into unclosed quotes,
+        corrupting the entire config.
+        """
+        target = tmp_path / "config.yaml"
+        # Mirrors the default personalities + skin cursor shipped in cli.py.
+        data = {
+            "personalities": {
+                "kawaii": "kawaii desu~! (◕‿◕) ★ ♪ ヽ(>∀<☆)ノ",
+                "catgirl": "nya~! (=^･ω･^=) ฅ^•ﻌ•^ฅ",
+                "surfer": "Cowabunga! 🤙 totally rad bro",
+                "hype": "LET'S GOOOO!!! 🔥 LEGENDARY!",
+            },
+            "display": {"cursor": " ▉"},
+        }
+
+        atomic_yaml_write(target, data)
+
+        text = target.read_text(encoding="utf-8")
+        # No escape artifacts of any kind — real characters on disk.
+        assert "\\U" not in text
+        assert "\\u" not in text
+        # Real glyphs are present verbatim.
+        assert "🔥" in text
+        assert "(=^･ω･^=)" in text
+        # And it reloads to exactly what was written.
+        assert yaml.safe_load(text) == data

tui_gateway/server.py

@@ -1541,7 +1541,7 @@ def _save_cfg(cfg: dict):
 
     path = _hermes_home / "config.yaml"
     with open(path, "w", encoding="utf-8") as f:
-        yaml.safe_dump(cfg, f)
+        yaml.safe_dump(cfg, f, allow_unicode=True)
     with _cfg_lock:
         _cfg_cache = copy.deepcopy(cfg)
         _cfg_path = path

utils.py

@@ -211,7 +211,20 @@ def atomic_yaml_write(
     )
     try:
         with os.fdopen(fd, "w", encoding="utf-8") as f:
-            yaml.dump(data, f, default_flow_style=default_flow_style, sort_keys=sort_keys)
+            # allow_unicode=True writes emoji/kaomoji (e.g. personalities, skin
+            # cursors) as real UTF-8 instead of fragile escape sequences. Without
+            # it, PyYAML emits astral-plane chars as `\UXXXXXXXX` (8-digit) escapes
+            # inside multi-line double-quoted strings wrapped with `\`
+            # continuations — a structure that stricter/non-PyYAML parsers and
+            # hand-edits routinely break into unclosed quotes, corrupting the whole
+            # config (GitHub #51356).
+            yaml.dump(
+                data,
+                f,
+                default_flow_style=default_flow_style,
+                sort_keys=sort_keys,
+                allow_unicode=True,
+            )
             if extra_content:
                 f.write(extra_content)
             f.flush()