diff --git a/docsgpt/deploy/commands.py b/docsgpt/deploy/commands.py
index 25a7d9a0..295ae0ac 100644
--- a/docsgpt/deploy/commands.py
+++ b/docsgpt/deploy/commands.py
@@ -215,30 +215,32 @@ def _redis_urls(base: str) -> dict[str, str]:
         parts = urlsplit(base)
     except ValueError as exc:
         # urlsplit raises on things like redis://[::1 ; that is a typo, not a crash.
-        raise DeployError(f"the Redis URL {base!r} could not be read: {exc}") from exc
+        raise DeployError(f"the Redis URL could not be read: {_scrub(str(exc), base)}") from exc
     try:
         port = parts.port  # a non-numeric or out-of-range port raises here, not when the URL is split
     except ValueError as exc:
         raise DeployError(
-            f"the Redis URL {base!r} has an unusable port: {exc}. Pass a URL like "
+            f"the Redis URL ({_endpoint(base)}) has an unusable port: {_scrub(str(exc), base)}. "
+            "Pass a URL like "
             "redis://host:6379 or redis://host:6379/5."
         ) from exc
     if port == 0:
         # urlsplit is happy with it, since 0 is inside the range, but nothing can connect to it.
         raise DeployError(
-            f"the Redis URL {base!r} has an unusable port: 0. Pass a URL like "
+            f"the Redis URL ({_endpoint(base)}) has an unusable port: 0. Pass a URL like "
             "redis://host:6379 or redis://host:6379/5."
         )
     if parts.scheme not in ("redis", "rediss"):
         raise DeployError(
-            f"the Redis URL {base!r} should start with redis:// or rediss://, with any options as "
+            f"the Redis URL ({_endpoint(base)}) should start with redis:// or rediss://, with any options as "
             "query parameters, so the broker, the result backend and the cache can be given a "
             "database each."
         )
     path = parts.path.rstrip("/").lstrip("/")
     if path and not (path.isascii() and path.isdigit()):
         raise DeployError(
-            f"the Redis URL {base!r} has {path!r} where a database number would go. Pass a URL like "
+            f"the Redis URL ({_endpoint(base)}) has {path[:20]!r} where a database number would go. "
+            "Pass a URL like "
             "redis://host:6379 or redis://host:6379/5."
         )
     try:
@@ -247,7 +249,7 @@ def _redis_urls(base: str) -> dict[str, str]:
         # Python refuses to convert a digit string past its conversion limit, and that is a typo
         # rather than a crash.
         raise DeployError(
-            f"the Redis URL {base!r} has a database number too long to read. Pass a URL like "
+            f"the Redis URL ({_endpoint(base)}) has a database number too long to read. Pass a URL like "
             "redis://host:6379 or redis://host:6379/5."
         ) from exc
     return {
@@ -848,6 +850,10 @@ def _endpoint(url: str) -> str:
         return "the configured URL"
     if port:
         host = f"{host}:{port}"
+    # The path is capped: this string is for a person to read, and it goes into terminals, CI logs
+    # and error messages. A 5000-digit database number would otherwise flood all three.
+    if len(path) > 40:
+        path = f"{path[:40]}..."
     return f"{scheme}://{host}{path}" if host else "the configured URL"
 
 
diff --git a/tests/deploy/test_doctor.py b/tests/deploy/test_doctor.py
index eb085038..e3072249 100644
--- a/tests/deploy/test_doctor.py
+++ b/tests/deploy/test_doctor.py
@@ -472,6 +472,28 @@ class TestRedisSelection:
         assert chosen == {"broker": "redis://localhost:6379/0"}
 
 
+class TestRedisUrlErrors:
+    """The validator raises before any check runs, and cli.main prints what it raises."""
+
+    SECRET = "sUpErSeCrEt"
+
+    @pytest.mark.parametrize("url", [
+        "redis://user:sUpErSeCrEt@host:not-a-port/0",
+        "redis://user:sUpErSeCrEt@host:0/0",
+        "redis://user:sUpErSeCrEt@host:6379/queue",
+        "postgres://user:sUpErSeCrEt@host:6379/0",
+        "redis://user:sUpErSeCrEt@host:6379/" + "1" * 5000,
+    ])
+    def test_a_rejected_url_never_carries_its_password_into_the_error(self, tmp_path, url):
+        (tmp_path / ".env").write_text("LLM_PROVIDER=docsgpt\n", encoding="utf-8")
+        with pytest.raises(DeployError) as raised:
+            _run(["doctor", "--dir", str(tmp_path), "--redis-url", url], _context())
+        message = str(raised.value)
+        assert self.SECRET not in message
+        assert "user" not in message
+        assert len(message) < 400, "an over-long database number must not come back in the message"
+
+
 class TestDoctor:
     def _only(self, monkeypatch, postgres, redis):
         monkeypatch.setattr(commands, "_check_postgres", lambda uri: postgres)