diff --git a/raven/cli/deep_research_commands.py b/raven/cli/deep_research_commands.py
index a6e796b20..d2cb64033 100644
--- a/raven/cli/deep_research_commands.py
+++ b/raven/cli/deep_research_commands.py
@@ -92,7 +92,7 @@ def configure_deep_research(*, non_interactive: bool = False, warnings: Optional
     """
     warnings = warnings if warnings is not None else []
     from raven.cli._styles import RAVEN_STYLE
-    from raven.cli.onboard_commands import _QMARK, _prompt_api_key, _require_questionary, _t, console
+    from raven.cli.onboard_commands import _BACK, _QMARK, _prompt_api_key, _require_questionary, _t, console
 
     if non_interactive:
         warnings.append("deep_research: skipped (non-interactive; pass --key to configure)")
@@ -142,7 +142,13 @@ def configure_deep_research(*, non_interactive: bool = False, warnings: Optional
     )
 
     while True:
-        key = _prompt_api_key("deep_research")
+        key = _prompt_api_key(
+            "deep_research",
+            allow_back=True,
+            back_label=_t("empty ↵ to cancel", "留空回车取消"),
+        )
+        if key is _BACK:
+            return False  # empty submit cancels configuration
         res = _validate_key(key, current["api_base"])
         if res["ok"]:
             break
diff --git a/raven/cli/onboard_commands.py b/raven/cli/onboard_commands.py
index f92bc9c8d..39052d44c 100644
--- a/raven/cli/onboard_commands.py
+++ b/raven/cli/onboard_commands.py
@@ -373,16 +373,18 @@ def _validate_provider_name(name: str) -> str:
     return candidate
 
 
-def _back_placeholder(allow_back: bool) -> Any:
-    """A faint in-field placeholder telling the user an empty submit rewinds.
+def _back_placeholder(allow_back: bool, label: Optional[str] = None) -> Any:
+    """A faint in-field placeholder telling the user what an empty submit does.
 
     Rendered greyed inside the input (via prompt_toolkit's ``placeholder``),
     it disappears the moment they type and leaves nothing behind once the
-    prompt is answered. Returns ``None`` when back isn't offered.
+    prompt is answered. Returns ``None`` when back isn't offered. ``label``
+    overrides the default "go back" wording for prompts where an empty submit
+    means something else (e.g. cancelling rather than rewinding a step).
     """
     if not allow_back:
         return None
-    return [("fg:#6c6c6c italic", _t("empty ↵ to go back", "留空回车返回上一步"))]
+    return [("fg:#6c6c6c italic", label or _t("empty ↵ to go back", "留空回车返回上一步"))]
 
 
 def _field_placeholder(allow_back: bool, required: bool) -> Any:
@@ -453,18 +455,19 @@ def _select_provider() -> Optional[str]:
     return picked  # None on Ctrl+C
 
 
-def _prompt_api_key(provider: str, *, allow_back: bool = False) -> Any:
+def _prompt_api_key(provider: str, *, allow_back: bool = False, back_label: Optional[str] = None) -> Any:
     """Ask for an API key (hidden input). Returns ``_BACK`` on empty submit
-    when ``allow_back`` is set, else the key string."""
+    when ``allow_back`` is set, else the key string. ``back_label`` overrides
+    the empty-submit hint for callers where it cancels rather than rewinds."""
     questionary = _require_questionary()
     from raven.cli._styles import RAVEN_STYLE
 
     def _validate(v: str) -> Any:
         if allow_back and v == "":
-            return True  # empty is the back signal, not an error
+            return True  # a truly-empty submit is the back/cancel signal
         return (
             True
-            if len(v) >= 8
+            if len(v.strip()) >= 8
             else _t(
                 "API key looks off (empty or too short) — please re-enter (≥ 8 chars).",
                 "API Key 看起来不对(过短或为空),请重新输入(至少 8 位)。",
@@ -474,7 +477,7 @@ def _validate(v: str) -> Any:
     key = questionary.password(
         _t("Paste your API key:", "粘贴你的 API Key:"),
         validate=_validate,
-        placeholder=_back_placeholder(allow_back),
+        placeholder=_back_placeholder(allow_back, back_label),
         style=RAVEN_STYLE,
         qmark=_QMARK,
     ).ask()
diff --git a/tests/test_cli_deep_research_commands.py b/tests/test_cli_deep_research_commands.py
index f3446f036..ece518d46 100644
--- a/tests/test_cli_deep_research_commands.py
+++ b/tests/test_cli_deep_research_commands.py
@@ -183,6 +183,47 @@ def test_configure_validation_fail_then_cancel(tmp_path: Path, monkeypatch):
     assert configure_deep_research(non_interactive=False, warnings=[]) is False  # cancelled, nothing written
 
 
+def test_configure_key_empty_submit_cancels(tmp_path: Path, monkeypatch):
+    """Empty submit at the key prompt (``_prompt_api_key`` returns ``_BACK``)
+    cancels configuration: returns False and writes nothing -- the missing
+    pre-key cancel path that used to force a Ctrl+C / whole-process exit."""
+    import raven.cli.onboard_commands as ob
+
+    p = tmp_path / "config.json"
+    monkeypatch.setattr(ut, "get_config_path", lambda: p)
+    monkeypatch.setattr(ob, "_require_questionary", lambda: _FakeQuestionary(["configure"]))
+
+    captured: dict = {}
+
+    def _fake_prompt(*a, **k):
+        captured.update(k)
+        return ob._BACK
+
+    monkeypatch.setattr(ob, "_prompt_api_key", _fake_prompt)
+
+    assert configure_deep_research(non_interactive=False, warnings=[]) is False
+    assert not p.exists() or "deepResearch" not in json.loads(p.read_text()).get("tools", {})
+    # the prompt is asked with a cancel-worded hint, not the default "go back"
+    assert captured.get("allow_back") is True
+    assert captured.get("back_label")
+
+
+def test_configure_reconfigure_key_empty_submit_cancels(tmp_path: Path, monkeypatch):
+    """Reconfigure path (already configured): empty submit at the key prompt
+    cancels and leaves the existing key untouched, instead of exiting raven --
+    the ``raven deep-research enable`` -> Reconfigure repro."""
+    import raven.cli.onboard_commands as ob
+
+    p = tmp_path / "config.json"
+    monkeypatch.setattr(ut, "get_config_path", lambda: p)
+    ut.set_deep_research({"api_key": "sk-old", "model": "m"}, config_path=p)
+    monkeypatch.setattr(ob, "_require_questionary", lambda: _FakeQuestionary(["reconfigure"]))
+    monkeypatch.setattr(ob, "_prompt_api_key", lambda *a, **k: ob._BACK)
+
+    assert configure_deep_research(non_interactive=False, warnings=[]) is False
+    assert json.loads(p.read_text())["tools"]["deepResearch"]["apiKey"] == "sk-old"  # unchanged
+
+
 def test_configure_validation_retry_then_ok(tmp_path: Path, monkeypatch):
     calls = {"n": 0}
 
diff --git a/tests/test_cli_onboard_commands.py b/tests/test_cli_onboard_commands.py
index da689e8b7..82f6dbbc1 100644
--- a/tests/test_cli_onboard_commands.py
+++ b/tests/test_cli_onboard_commands.py
@@ -666,6 +666,55 @@ def _fake_autocomplete(message, choices, default=None, **kwargs):
     assert data["agents"]["defaults"]["model"] == "claude-haiku-4-5"
 
 
+def _capture_password_validate(monkeypatch: pytest.MonkeyPatch, answer: str) -> dict[str, Any]:
+    """Stub ``questionary.password`` to record the ``validate`` callable the
+    prompt installs and return ``answer`` from ``.ask()``."""
+    import questionary
+
+    captured: dict[str, Any] = {}
+
+    class _FakeQuestion:
+        def ask(self) -> Any:
+            return answer
+
+    def _fake_password(message: Any, *, validate: Any = None, **kwargs: Any) -> Any:
+        captured["validate"] = validate
+        return _FakeQuestion()
+
+    monkeypatch.setattr(questionary, "password", _fake_password)
+    return captured
+
+
+def test_prompt_api_key_validator_rejects_whitespace_only(monkeypatch: pytest.MonkeyPatch) -> None:
+    """An all-whitespace (or empty) key must fail the field validator (which
+    re-prompts) rather than pass the raw length check, strip to empty, and hit
+    ``typer.Exit`` (which quit raven with no message)."""
+    captured = _capture_password_validate(monkeypatch, "sk-realkey123")
+
+    key = onboard_commands._prompt_api_key("deep_research")
+    assert key == "sk-realkey123"
+
+    validate = captured["validate"]
+    assert validate("        ") is not True
+    assert validate("") is not True
+    assert validate("sk-12345678") is True
+
+
+def test_prompt_api_key_empty_is_back_but_whitespace_rejected(monkeypatch: pytest.MonkeyPatch) -> None:
+    """With ``allow_back``, only a truly-empty submit is the back/cancel signal;
+    a whitespace-only entry is still rejected as an invalid key (re-prompt), not
+    silently treated as back."""
+    captured = _capture_password_validate(monkeypatch, "")
+
+    result = onboard_commands._prompt_api_key("deep_research", allow_back=True)
+    assert result is onboard_commands._BACK
+
+    validate = captured["validate"]
+    assert validate("") is True  # truly-empty submit rewinds/cancels
+    assert validate("        ") is not True  # whitespace rejected, not back
+    assert validate("sk-12345678") is True
+
+
 def test_format_model_for_provider_prefix_rules() -> None:
     """Provider's ``litellm_prefix`` is applied unless model_id already has one."""
     from raven.providers.registry import find_by_name