diff --git a/docs/en/services.md b/docs/en/services.md
index a6d7be58..b0f420c3 100644
--- a/docs/en/services.md
+++ b/docs/en/services.md
@@ -17,6 +17,9 @@ reme start
 reme start service.host=127.0.0.1 service.port=8181
 ```
 
+IPv6 literals such as `::1` can be used as the host; ReMe formats them correctly when HTTP or MCP clients connect.
+If a service binds to the IPv6 wildcard `::`, in-process clients use the connectable loopback address `::1`.
+
 From another terminal, call a Job through the CLI client:
 
 ```bash
diff --git a/docs/zh/services.md b/docs/zh/services.md
index 44f0b17f..34e6a7ae 100644
--- a/docs/zh/services.md
+++ b/docs/zh/services.md
@@ -17,6 +17,9 @@ reme start
 reme start service.host=127.0.0.1 service.port=8181
 ```
 
+主机地址也可以使用 `::1` 等 IPv6 字面量；HTTP 和 MCP client 会在连接时正确格式化该地址。
+如果服务绑定到 IPv6 通配地址 `::`，ReMe 会向进程内 client 提供可连接的回环地址 `::1`。
+
 在另一个终端通过 CLI client 调用 Job：
 
 ```bash
diff --git a/reme/components/client/base_client.py b/reme/components/client/base_client.py
index a3b34879..e2296d06 100644
--- a/reme/components/client/base_client.py
+++ b/reme/components/client/base_client.py
@@ -5,6 +5,8 @@ import os
 from abc import abstractmethod
 from collections.abc import AsyncGenerator
 
+import httpx
+
 from ..base_component import BaseComponent
 from ...constants import (
     REME_DEFAULT_HOST,
@@ -38,6 +40,11 @@ class BaseClient(BaseComponent):
             port = port or fallback_port
         return normalize_connect_host(host), port
 
+    @staticmethod
+    def _build_service_url(host: str, port: int, path: str = "") -> str:
+        """Build a valid HTTP URL for the resolved service address, including IPv6 literals."""
+        return str(httpx.URL(scheme="http", host=host, port=port, path=path))
+
     async def _start(self) -> None:
         """Initialize the client."""
 
diff --git a/reme/components/client/http_client.py b/reme/components/client/http_client.py
index ccd7ee62..d9ae1b50 100644
--- a/reme/components/client/http_client.py
+++ b/reme/components/client/http_client.py
@@ -26,7 +26,7 @@ class HttpClient(BaseClient):
         super().__init__(**kwargs)
 
         host, port = self._resolve_service_address(host, port)
-        self.base_url = f"http://{host}:{port}"
+        self.base_url = self._build_service_url(host, port)
         self.timeout = timeout
         self.show_metadata = show_metadata
 
diff --git a/reme/components/client/mcp_client.py b/reme/components/client/mcp_client.py
index b3f4277d..4eab90b4 100644
--- a/reme/components/client/mcp_client.py
+++ b/reme/components/client/mcp_client.py
@@ -72,7 +72,7 @@ class MCPClient(BaseClient):
             return cls(command=command, args=args)
 
         path = "/sse" if self.transport == "sse" else "/mcp"
-        url = f"http://{self.host}:{self.port}{path}"
+        url = self._build_service_url(self.host, self.port, path)
         return cls(url=url)
 
     # pylint: disable=unnecessary-dunder-call
diff --git a/reme/components/codex_app_server.py b/reme/components/codex_app_server.py
index 1412b4b1..780359ea 100644
--- a/reme/components/codex_app_server.py
+++ b/reme/components/codex_app_server.py
@@ -429,7 +429,6 @@ class CodexAppServer(BaseComponent):
         ):
             if self._http_url is None:
                 host = normalize_connect_host(service.host)
-                host = "::1" if host == "::" else host
                 # Background jobs can run before uvicorn finishes binding the main listener.
                 async with asyncio.timeout(30):
                     while True:
diff --git a/reme/constants.py b/reme/constants.py
index a3839beb..4e7635af 100644
--- a/reme/constants.py
+++ b/reme/constants.py
@@ -4,17 +4,23 @@ REME_SERVICE_INFO = "REME_SERVICE_INFO"
 
 # Loopback address used by services and clients unless a host is configured.
 REME_DEFAULT_HOST = "127.0.0.1"
+REME_IPV6_LOOPBACK_HOST = "::1"
 
 # Wildcard address accepted when a service is explicitly configured to listen
 # on every IPv4 interface.
 REME_WILDCARD_BIND_HOST = "0.0.0.0"
+REME_IPV6_WILDCARD_BIND_HOST = "::"
 
 REME_DEFAULT_PORT = 2333
 
 
 def normalize_connect_host(host: str) -> str:
-    """Return a local destination for an address used only for binding."""
-    return REME_DEFAULT_HOST if host == REME_WILDCARD_BIND_HOST else host
+    """Return a local destination for a configured bind address."""
+    if host == REME_WILDCARD_BIND_HOST:
+        return REME_DEFAULT_HOST
+    if host == REME_IPV6_WILDCARD_BIND_HOST:
+        return REME_IPV6_LOOPBACK_HOST
+    return host
 
 
 # CRUD steps: file IO limits and truncation marker (shared across CRUD steps).
diff --git a/reme/utils/service_utils.py b/reme/utils/service_utils.py
index 9e79187d..cdce6ecf 100644
--- a/reme/utils/service_utils.py
+++ b/reme/utils/service_utils.py
@@ -24,10 +24,12 @@ async def find_reme(host: str, port: int) -> str:
         return "reme"
     except Exception:
         pass
-    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+    family = socket.AF_INET6 if ":" in host else socket.AF_INET
+    probe_host = normalize_connect_host(host)
+    with socket.socket(family, socket.SOCK_STREAM) as s:
         s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
         try:
-            s.bind((host, port))
+            s.bind((probe_host, port))
             return "free"
         except OSError:
             return "occupied"
diff --git a/tests/unit/test_base_client.py b/tests/unit/test_base_client.py
index ada9e8a2..a535be37 100644
--- a/tests/unit/test_base_client.py
+++ b/tests/unit/test_base_client.py
@@ -31,6 +31,19 @@ def test_explicit_host_only_keeps_host_and_defaults_port():
     assert client.port == REME_DEFAULT_PORT
 
 
+def test_ipv6_host_builds_a_valid_http_base_url():
+    """IPv6 literals are bracketed by URL construction rather than string interpolation."""
+    assert HttpClient(host="::1", port=8123).base_url == "http://[::1]:8123"
+
+
+def test_ipv6_wildcard_bind_host_resolves_to_loopback_destination():
+    """An IPv6 wildcard listener advertises a connectable IPv6 loopback address."""
+    assert HttpClient(host="::", port=8123).base_url == "http://[::1]:8123"
+
+    client = MCPClient(host="::", port=8123)
+    assert client.host == "::1"
+
+
 def test_explicit_fields_win_over_service_discovery(monkeypatch):
     """Discovery fills only the missing field; explicit fields are kept."""
     monkeypatch.setenv(REME_SERVICE_INFO, '{"host": "10.0.0.1", "port": 9000}')
@@ -59,6 +72,13 @@ def test_service_discovery_fills_both_fields_when_nothing_is_explicit(monkeypatc
     assert client.port == 9000
 
 
+def test_ipv6_service_discovery_builds_a_valid_http_base_url(monkeypatch):
+    """Discovered IPv6 service addresses use the same URL-safe construction."""
+    monkeypatch.setenv(REME_SERVICE_INFO, '{"host": "::1", "port": 9000}')
+
+    assert HttpClient().base_url == "http://[::1]:9000"
+
+
 def test_invalid_service_info_keeps_explicit_fields_and_defaults_the_rest(monkeypatch):
     """An undecodable discovery payload still preserves explicit fields."""
     monkeypatch.setenv(REME_SERVICE_INFO, "not-json")
diff --git a/tests/unit/test_mcp_client.py b/tests/unit/test_mcp_client.py
index e96a1d3d..78558c7d 100644
--- a/tests/unit/test_mcp_client.py
+++ b/tests/unit/test_mcp_client.py
@@ -28,6 +28,17 @@ def test_mcp_client_converts_wildcard_bind_address_to_loopback():
     assert client.port == 8123
 
 
+@pytest.mark.parametrize(
+    ("transport", "expected_path"),
+    [("sse", "/sse"), ("streamable-http", "/mcp")],
+)
+def test_mcp_client_brackets_ipv6_service_addresses(transport, expected_path):
+    """Both network MCP transports construct valid URLs for IPv6 literals."""
+    client = MCPClient(transport=transport, host="::1", port=8123)
+
+    assert client._build_transport().url == f"http://[::1]:8123{expected_path}"
+
+
 @pytest.mark.asyncio
 async def test_mcp_catalog_uses_sdk_field_names():
     """Tool catalogs expose SDK 2 fields while preserving schemas and user metadata."""
diff --git a/tests/unit/test_service.py b/tests/unit/test_service.py
index 07b45d94..106ec560 100644
--- a/tests/unit/test_service.py
+++ b/tests/unit/test_service.py
@@ -231,6 +231,8 @@ def test_network_services_accept_explicit_wildcard_bind():
     """Remote access remains available through explicit service configuration."""
     assert HttpService(host="0.0.0.0").host == "0.0.0.0"
     assert MCPService(host="0.0.0.0").host == "0.0.0.0"
+    assert HttpService(host="::").host == "::"
+    assert MCPService(host="::").host == "::"
 
 
 def test_service_lifespan_advertises_loopback_for_wildcard_bind(monkeypatch):
@@ -244,3 +246,16 @@ def test_service_lifespan_advertises_loopback_for_wildcard_bind(monkeypatch):
             assert json.loads(os.environ[REME_SERVICE_INFO]) == {"host": "127.0.0.1", "port": 8123}
 
     asyncio.run(run())
+
+
+def test_service_lifespan_advertises_ipv6_loopback_for_ipv6_wildcard(monkeypatch):
+    """IPv6 wildcard binds are translated to a connectable in-process address."""
+    monkeypatch.delenv(REME_SERVICE_INFO, raising=False)
+
+    async def run():
+        app = _dummy_app()
+        lifespan = HttpService()._lifespan(app, "::", 8123)  # pylint: disable=protected-access
+        async with lifespan(None):
+            assert json.loads(os.environ[REME_SERVICE_INFO]) == {"host": "::1", "port": 8123}
+
+    asyncio.run(run())
diff --git a/tests/unit/test_service_utils.py b/tests/unit/test_service_utils.py
index fbed446a..5c6df774 100644
--- a/tests/unit/test_service_utils.py
+++ b/tests/unit/test_service_utils.py
@@ -174,9 +174,55 @@ def test_scan_reme_procs_skips_access_denied(monkeypatch):
 
 def test_connect_host_converts_wildcard_bind_address():
     assert normalize_connect_host("0.0.0.0") == "127.0.0.1"
+    assert normalize_connect_host("::") == "::1"
     assert normalize_connect_host("192.0.2.10") == "192.0.2.10"
 
 
+@pytest.mark.asyncio
+async def test_find_reme_uses_ipv6_for_wildcard_listener_probe(monkeypatch):
+    """IPv6 listener probes use IPv6 sockets and clients connect through loopback."""
+    probed_hosts = []
+
+    class FailedProbeClient:
+        """Client probe that simulates no running service."""
+
+        def __init__(self, *, host, **_kwargs):
+            probed_hosts.append(host)
+
+        async def __aenter__(self):
+            raise OSError("no running service")
+
+        async def __aexit__(self, *_args):
+            return None
+
+    socket_families = []
+
+    class FakeSocket:
+        """Socket probe that records the selected address family."""
+
+        def __init__(self, family, _kind):
+            socket_families.append(family)
+
+        def __enter__(self):
+            return self
+
+        def __exit__(self, *_args):
+            return None
+
+        def setsockopt(self, *_args):
+            return None
+
+        def bind(self, address):
+            assert address == ("::1", 8123)
+
+    monkeypatch.setattr("reme.components.client.http_client.HttpClient", FailedProbeClient)
+    monkeypatch.setattr(su.socket, "socket", FakeSocket)
+
+    assert await su.find_reme("::", 8123) == "free"
+    assert probed_hosts == ["::1"]
+    assert socket_families == [socket.AF_INET6]
+
+
 def test_running_app_config_preserves_plugins(monkeypatch):
     """Process replay exposes the full config while the compatibility helper returns service only."""
     monkeypatch.setattr(su, "_reme_start_argv", lambda: [["config=example"]])