diff --git a/tests/tui_gateway/test_make_agent_provider.py b/tests/tui_gateway/test_make_agent_provider.py
index bdc7fecf4..9fc78882e 100644
--- a/tests/tui_gateway/test_make_agent_provider.py
+++ b/tests/tui_gateway/test_make_agent_provider.py
@@ -27,16 +27,22 @@ def test_make_agent_passes_resolved_provider():
         "agent": {"system_prompt": "test"},
     }
 
-    with patch("tui_gateway.server._load_cfg", return_value=fake_cfg), \
-         patch("tui_gateway.server._get_db", return_value=MagicMock()), \
-         patch("tui_gateway.server._load_tool_progress_mode", return_value="compact"), \
-         patch("tui_gateway.server._load_reasoning_config", return_value=None), \
-         patch("tui_gateway.server._load_service_tier", return_value=None), \
-         patch("tui_gateway.server._load_enabled_toolsets", return_value=None), \
-         patch("hermes_cli.runtime_provider.resolve_runtime_provider", return_value=fake_runtime) as mock_resolve, \
-         patch("run_agent.AIAgent") as mock_agent:
+    with (
+        patch("tui_gateway.server._load_cfg", return_value=fake_cfg),
+        patch("tui_gateway.server._get_db", return_value=MagicMock()),
+        patch("tui_gateway.server._load_tool_progress_mode", return_value="compact"),
+        patch("tui_gateway.server._load_reasoning_config", return_value=None),
+        patch("tui_gateway.server._load_service_tier", return_value=None),
+        patch("tui_gateway.server._load_enabled_toolsets", return_value=None),
+        patch(
+            "hermes_cli.runtime_provider.resolve_runtime_provider",
+            return_value=fake_runtime,
+        ) as mock_resolve,
+        patch("run_agent.AIAgent") as mock_agent,
+    ):
 
         from tui_gateway.server import _make_agent
+
         _make_agent("sid-1", "key-1")
 
         mock_resolve.assert_called_once_with(requested=None)
@@ -46,3 +52,98 @@ def test_make_agent_passes_resolved_provider():
         assert call_kwargs.kwargs["base_url"] == "https://api.anthropic.com"
         assert call_kwargs.kwargs["api_key"] == "sk-test-key"
         assert call_kwargs.kwargs["api_mode"] == "anthropic_messages"
+
+
+def test_probe_config_health_flags_null_sections():
+    """Bare YAML keys (`agent:` with no value) parse as None and silently
+    drop nested settings; probe must surface them so users can fix."""
+    from tui_gateway.server import _probe_config_health
+
+    assert _probe_config_health({"agent": {"x": 1}}) == ""
+    assert _probe_config_health({}) == ""
+
+    msg = _probe_config_health({"agent": None, "display": None, "model": {}})
+    assert "agent" in msg and "display" in msg
+    assert "model" not in msg
+
+
+def test_probe_config_health_flags_null_personalities_with_active_personality():
+    from tui_gateway.server import _probe_config_health
+
+    msg = _probe_config_health(
+        {
+            "agent": {"personalities": None},
+            "display": {"personality": "kawaii"},
+            "model": {},
+        }
+    )
+    assert "display.personality" in msg
+    assert "agent.personalities" in msg
+
+
+def test_make_agent_tolerates_null_config_sections():
+    """Bare `agent:` / `display:` keys in ~/.hermes/config.yaml parse as
+    None. cfg.get("agent", {}) returns None (default only fires on missing
+    key), so downstream .get() chains must be guarded. Reported via Twitter
+    against the new TUI."""
+
+    fake_runtime = {
+        "provider": "openrouter",
+        "base_url": "https://api.synthetic.new/v1",
+        "api_key": "sk-test",
+        "api_mode": "chat_completions",
+        "command": None,
+        "args": None,
+        "credential_pool": None,
+    }
+    null_cfg = {"agent": None, "display": None, "model": {"default": "glm-5"}}
+
+    with (
+        patch("tui_gateway.server._load_cfg", return_value=null_cfg),
+        patch("tui_gateway.server._get_db", return_value=MagicMock()),
+        patch(
+            "hermes_cli.runtime_provider.resolve_runtime_provider",
+            return_value=fake_runtime,
+        ),
+        patch("run_agent.AIAgent") as mock_agent,
+    ):
+
+        from tui_gateway.server import _make_agent
+
+        _make_agent("sid-null", "key-null")
+
+        assert mock_agent.called
+
+
+def test_make_agent_tolerates_null_personalities_with_active_personality():
+    fake_runtime = {
+        "provider": "openrouter",
+        "base_url": "https://api.synthetic.new/v1",
+        "api_key": "sk-test",
+        "api_mode": "chat_completions",
+        "command": None,
+        "args": None,
+        "credential_pool": None,
+    }
+    cfg = {
+        "agent": {"personalities": None},
+        "display": {"personality": "kawaii"},
+        "model": {"default": "glm-5"},
+    }
+
+    with (
+        patch("tui_gateway.server._load_cfg", return_value=cfg),
+        patch("tui_gateway.server._get_db", return_value=MagicMock()),
+        patch("cli.load_cli_config", return_value={"agent": {"personalities": None}}),
+        patch(
+            "hermes_cli.runtime_provider.resolve_runtime_provider",
+            return_value=fake_runtime,
+        ),
+        patch("run_agent.AIAgent") as mock_agent,
+    ):
+        from tui_gateway.server import _make_agent
+
+        _make_agent("sid-null-personality", "key-null-personality")
+
+        assert mock_agent.called
+        assert mock_agent.call_args.kwargs["ephemeral_system_prompt"] is None
diff --git a/tui_gateway/server.py b/tui_gateway/server.py
index cc2d7b08d..e919c7c98 100644
--- a/tui_gateway/server.py
+++ b/tui_gateway/server.py
@@ -61,7 +61,11 @@ def _panic_hook(exc_type, exc_value, exc_tb):
     # Stderr goes through to the TUI as a gateway.stderr Activity line —
     # the first line here is what the user will see without opening any
     # log files.  Rest of the stack is still in the log for full context.
-    first = str(exc_value).strip().splitlines()[0] if str(exc_value).strip() else exc_type.__name__
+    first = (
+        str(exc_value).strip().splitlines()[0]
+        if str(exc_value).strip()
+        else exc_type.__name__
+    )
     print(f"[gateway-crash] {exc_type.__name__}: {first}", file=sys.stderr, flush=True)
     # Chain to the default hook so the process still terminates normally.
     sys.__excepthook__(exc_type, exc_value, exc_tb)
@@ -593,13 +597,17 @@ def _coerce_statusbar(raw) -> str:
 def _load_reasoning_config() -> dict | None:
     from hermes_constants import parse_reasoning_effort
 
-    effort = str(_load_cfg().get("agent", {}).get("reasoning_effort", "") or "").strip()
+    effort = str(
+        (_load_cfg().get("agent") or {}).get("reasoning_effort", "") or ""
+    ).strip()
     return parse_reasoning_effort(effort)
 
 
 def _load_service_tier() -> str | None:
     raw = (
-        str(_load_cfg().get("agent", {}).get("service_tier", "") or "").strip().lower()
+        str((_load_cfg().get("agent") or {}).get("service_tier", "") or "")
+        .strip()
+        .lower()
     )
     if not raw or raw in {"normal", "default", "standard", "off", "none"}:
         return None
@@ -609,11 +617,11 @@ def _load_service_tier() -> str | None:
 
 
 def _load_show_reasoning() -> bool:
-    return bool(_load_cfg().get("display", {}).get("show_reasoning", False))
+    return bool((_load_cfg().get("display") or {}).get("show_reasoning", False))
 
 
 def _load_tool_progress_mode() -> str:
-    raw = _load_cfg().get("display", {}).get("tool_progress", "all")
+    raw = (_load_cfg().get("display") or {}).get("tool_progress", "all")
     if raw is False:
         return "off"
     if raw is True:
@@ -816,6 +824,39 @@ def _probe_credentials(agent) -> str:
     return ""
 
 
+def _probe_config_health(cfg: dict) -> str:
+    """Flag bare YAML keys (`agent:` with no value → None) that silently
+    drop nested settings. Returns warning or ''."""
+    if not isinstance(cfg, dict):
+        return ""
+    warnings: list[str] = []
+    null_keys = sorted(k for k, v in cfg.items() if v is None)
+    if not null_keys:
+        pass
+    else:
+        keys = ", ".join(f"`{k}`" for k in null_keys)
+        warnings.append(
+            f"config.yaml has empty section(s): {keys}. "
+            f"Remove the line(s) or set them to `{{}}` — "
+            f"empty sections silently drop nested settings."
+        )
+    display_cfg = cfg.get("display")
+    agent_cfg = cfg.get("agent")
+    if isinstance(display_cfg, dict):
+        personality = str(display_cfg.get("personality", "") or "").strip().lower()
+        if (
+            personality
+            and personality not in {"default", "none", "neutral"}
+            and isinstance(agent_cfg, dict)
+            and agent_cfg.get("personalities") is None
+        ):
+            warnings.append(
+                "`display.personality` is set but `agent.personalities` is empty/null; "
+                "personality overlay will be skipped."
+            )
+    return " ".join(warnings).strip()
+
+
 def _session_info(agent) -> dict:
     info: dict = {
         "model": getattr(agent, "model", ""),
@@ -1104,20 +1145,22 @@ def _wire_callbacks(sid: str):
 
 def _resolve_personality_prompt(cfg: dict) -> str:
     """Resolve the active personality into a system prompt string."""
-    name = (cfg.get("display", {}).get("personality", "") or "").strip().lower()
+    name = ((cfg.get("display") or {}).get("personality", "") or "").strip().lower()
     if not name or name in ("default", "none", "neutral"):
         return ""
     try:
         from cli import load_cli_config
 
-        personalities = load_cli_config().get("agent", {}).get("personalities", {})
+        personalities = (load_cli_config().get("agent") or {}).get("personalities", {}) or {}
     except Exception:
         try:
             from hermes_cli.config import load_config as _load_full_cfg
 
-            personalities = _load_full_cfg().get("agent", {}).get("personalities", {})
+            personalities = (
+                (_load_full_cfg().get("agent") or {}).get("personalities", {}) or {}
+            )
         except Exception:
-            personalities = cfg.get("agent", {}).get("personalities", {})
+            personalities = (cfg.get("agent") or {}).get("personalities", {}) or {}
     pval = personalities.get(name)
     if pval is None:
         return ""
@@ -1139,15 +1182,15 @@ def _available_personalities(cfg: dict | None = None) -> dict:
     try:
         from cli import load_cli_config
 
-        return load_cli_config().get("agent", {}).get("personalities", {}) or {}
+        return (load_cli_config().get("agent") or {}).get("personalities", {}) or {}
     except Exception:
         try:
             from hermes_cli.config import load_config as _load_full_cfg
 
-            return _load_full_cfg().get("agent", {}).get("personalities", {}) or {}
+            return (_load_full_cfg().get("agent") or {}).get("personalities", {}) or {}
         except Exception:
             cfg = cfg or _load_cfg()
-            return cfg.get("agent", {}).get("personalities", {}) or {}
+            return (cfg.get("agent") or {}).get("personalities", {}) or {}
 
 
 def _validate_personality(value: str, cfg: dict | None = None) -> tuple[str, str]:
@@ -1257,7 +1300,7 @@ def _make_agent(sid: str, key: str, session_id: str | None = None):
     from hermes_cli.runtime_provider import resolve_runtime_provider
 
     cfg = _load_cfg()
-    system_prompt = cfg.get("agent", {}).get("system_prompt", "") or ""
+    system_prompt = (cfg.get("agent") or {}).get("system_prompt", "") or ""
     if not system_prompt:
         system_prompt = _resolve_personality_prompt(cfg)
     runtime = resolve_runtime_provider(requested=None)
@@ -1503,6 +1546,10 @@ def _(rid, params: dict) -> dict:
             warn = _probe_credentials(agent)
             if warn:
                 info["credential_warning"] = warn
+            cfg_warn = _probe_config_health(_load_cfg())
+            if cfg_warn:
+                info["config_warning"] = cfg_warn
+                logger.warning(cfg_warn)
             _emit("session.info", sid, info)
         except Exception as e:
             session["agent_error"] = str(e)
@@ -1649,9 +1696,7 @@ def _(rid, params: dict) -> dict:
         return _db_unavailable_error(rid, code=5007)
     title, key = params.get("title", ""), session["session_key"]
     if not title:
-        return _ok(
-            rid, {"title": db.get_session_title(key) or "", "session_key": key}
-        )
+        return _ok(rid, {"title": db.get_session_title(key) or "", "session_key": key})
     try:
         db.set_session_title(key, title)
         return _ok(rid, {"title": title})
@@ -2278,7 +2323,9 @@ def _(rid, params: dict) -> dict:
                     f.write(trace)
             except Exception:
                 pass
-            print(f"[gateway-turn] {type(e).__name__}: {e}", file=sys.stderr, flush=True)
+            print(
+                f"[gateway-turn] {type(e).__name__}: {e}", file=sys.stderr, flush=True
+            )
             _emit("error", sid, {"message": str(e)})
         finally:
             try:
@@ -2701,9 +2748,7 @@ def _(rid, params: dict) -> dict:
         cfg = _load_cfg()
         display = cfg.get("display") if isinstance(cfg.get("display"), dict) else {}
         sections_cfg = (
-            display.get("sections")
-            if isinstance(display.get("sections"), dict)
-            else {}
+            display.get("sections") if isinstance(display.get("sections"), dict) else {}
         )
 
         nv = str(value or "").strip().lower()
@@ -2838,18 +2883,21 @@ def _(rid, params: dict) -> dict:
         return _ok(rid, {"prompt": _load_cfg().get("custom_prompt", "")})
     if key == "skin":
         return _ok(
-            rid, {"value": _load_cfg().get("display", {}).get("skin", "default")}
+            rid, {"value": (_load_cfg().get("display") or {}).get("skin", "default")}
         )
     if key == "personality":
         return _ok(
-            rid, {"value": _load_cfg().get("display", {}).get("personality", "default")}
+            rid,
+            {"value": (_load_cfg().get("display") or {}).get("personality", "default")},
         )
     if key == "reasoning":
         cfg = _load_cfg()
-        effort = str(cfg.get("agent", {}).get("reasoning_effort", "medium") or "medium")
+        effort = str(
+            (cfg.get("agent") or {}).get("reasoning_effort", "medium") or "medium"
+        )
         display = (
             "show"
-            if bool(cfg.get("display", {}).get("show_reasoning", False))
+            if bool((cfg.get("display") or {}).get("show_reasoning", False))
             else "hide"
         )
         return _ok(rid, {"value": effort, "display": display})
@@ -2857,7 +2905,7 @@ def _(rid, params: dict) -> dict:
         allowed_dm = frozenset({"hidden", "collapsed", "expanded"})
         raw = (
             str(
-                _load_cfg().get("display", {}).get("details_mode", "collapsed")
+                (_load_cfg().get("display") or {}).get("details_mode", "collapsed")
                 or "collapsed"
             )
             .strip()
@@ -2868,13 +2916,17 @@ def _(rid, params: dict) -> dict:
     if key == "thinking_mode":
         allowed_tm = frozenset({"collapsed", "truncated", "full"})
         cfg = _load_cfg()
-        raw = str(cfg.get("display", {}).get("thinking_mode", "") or "").strip().lower()
+        raw = (
+            str((cfg.get("display") or {}).get("thinking_mode", "") or "")
+            .strip()
+            .lower()
+        )
         if raw in allowed_tm:
             nv = raw
         else:
             dm = (
                 str(
-                    cfg.get("display", {}).get("details_mode", "collapsed")
+                    (cfg.get("display") or {}).get("details_mode", "collapsed")
                     or "collapsed"
                 )
                 .strip()
@@ -2883,7 +2935,7 @@ def _(rid, params: dict) -> dict:
             nv = "full" if dm == "expanded" else "collapsed"
         return _ok(rid, {"value": nv})
     if key == "compact":
-        on = bool(_load_cfg().get("display", {}).get("tui_compact", False))
+        on = bool((_load_cfg().get("display") or {}).get("tui_compact", False))
         return _ok(rid, {"value": "on" if on else "off"})
     if key == "statusbar":
         display = _load_cfg().get("display")
@@ -3369,7 +3421,16 @@ def _list_repo_files(root: str) -> list[str]:
         if top_result.returncode == 0:
             top = top_result.stdout.decode("utf-8", "replace").strip()
             list_result = subprocess.run(
-                ["git", "-C", top, "ls-files", "-z", "--cached", "--others", "--exclude-standard"],
+                [
+                    "git",
+                    "-C",
+                    top,
+                    "ls-files",
+                    "-z",
+                    "--cached",
+                    "--others",
+                    "--exclude-standard",
+                ],
                 capture_output=True,
                 timeout=2.0,
                 check=False,
@@ -3378,7 +3439,9 @@ def _list_repo_files(root: str) -> list[str]:
                 for p in list_result.stdout.decode("utf-8", "replace").split("\0"):
                     if not p:
                         continue
-                    rel = os.path.relpath(os.path.join(top, p), root).replace(os.sep, "/")
+                    rel = os.path.relpath(os.path.join(top, p), root).replace(
+                        os.sep, "/"
+                    )
                     # Skip parents/siblings of cwd — keep the picker scoped
                     # to root-and-below, matching Cmd-P workspace semantics.
                     if rel.startswith("../"):
@@ -3512,12 +3575,7 @@ def _(rid, params: dict) -> dict:
         # editors like Cursor / VS Code do for Cmd-P. Path-ish queries (with
         # `/`, `./`, `~/`, `/abs`) fall through to the directory-listing
         # path so explicit navigation intent is preserved.
-        if (
-            is_context
-            and path_part
-            and "/" not in path_part
-            and prefix_tag != "folder"
-        ):
+        if is_context and path_part and "/" not in path_part and prefix_tag != "folder":
             root = os.getcwd()
             ranked: list[tuple[tuple[int, int], str, str]] = []
             for rel in _list_repo_files(root):
@@ -3721,7 +3779,7 @@ def _mirror_slash_side_effects(sid: str, session: dict, command: str) -> str:
             _apply_personality_to_session(sid, session, new_prompt)
         elif name == "prompt" and agent:
             cfg = _load_cfg()
-            new_prompt = cfg.get("agent", {}).get("system_prompt", "") or ""
+            new_prompt = (cfg.get("agent") or {}).get("system_prompt", "") or ""
             agent.ephemeral_system_prompt = new_prompt or None
             agent._cached_system_prompt = None
         elif name == "compress" and agent:
@@ -3943,9 +4001,7 @@ def _(rid, params: dict) -> dict:
 
             voice_cfg = _load_cfg().get("voice", {})
             start_continuous(
-                on_transcript=lambda t: _voice_emit(
-                    "voice.transcript", {"text": t}
-                ),
+                on_transcript=lambda t: _voice_emit("voice.transcript", {"text": t}),
                 on_status=lambda s: _voice_emit("voice.status", {"state": s}),
                 on_silent_limit=lambda: _voice_emit(
                     "voice.transcript", {"no_speech_limit": True}
diff --git a/ui-tui/src/app/useSessionLifecycle.ts b/ui-tui/src/app/useSessionLifecycle.ts
index acd10135e..baaf3fc3c 100644
--- a/ui-tui/src/app/useSessionLifecycle.ts
+++ b/ui-tui/src/app/useSessionLifecycle.ts
@@ -142,6 +142,10 @@ export function useSessionLifecycle(opts: UseSessionLifecycleOptions) {
         sys(`warning: ${info.credential_warning}`)
       }
 
+      if (info?.config_warning) {
+        sys(`warning: ${info.config_warning}`)
+      }
+
       if (msg) {
         sys(msg)
       }
diff --git a/ui-tui/src/gatewayTypes.ts b/ui-tui/src/gatewayTypes.ts
index a38e06804..91fced32a 100644
--- a/ui-tui/src/gatewayTypes.ts
+++ b/ui-tui/src/gatewayTypes.ts
@@ -93,7 +93,7 @@ export interface SetupStatusResponse {
 // ── Session lifecycle ────────────────────────────────────────────────
 
 export interface SessionCreateResponse {
-  info?: SessionInfo & { credential_warning?: string }
+  info?: SessionInfo & { config_warning?: string; credential_warning?: string }
   session_id: string
 }