diff --git a/plane_mcp/tools/work_items.py b/plane_mcp/tools/work_items.py
index c4726493..cc591882 100644
--- a/plane_mcp/tools/work_items.py
+++ b/plane_mcp/tools/work_items.py
@@ -25,6 +25,26 @@
 logger = get_logger(__name__)
 
 
+class _CreateWorkItemCompat(CreateWorkItem):
+    """CreateWorkItem that also serializes ``state_id`` for self-hosted CE.
+
+    Plane Cloud accepts ``state``; Community Edition accepts ``state_id``. The
+    wrong key is silently ignored (HTTP 200, state unchanged). Emitting both
+    keeps Cloud and CE working — see issue #183.
+    """
+
+    state_id: str | None = None
+
+
+class _UpdateWorkItemCompat(UpdateWorkItem):
+    """UpdateWorkItem that also serializes ``state_id`` for self-hosted CE.
+
+    See :class:`_CreateWorkItemCompat` and issue #183.
+    """
+
+    state_id: str | None = None
+
+
 def _resolve_description_html(description_html: str | None, description_stripped: str | None) -> str | None:
     """Resolve the description_html to persist.
 
@@ -228,7 +248,7 @@ def create_work_item(
             external_source: External system source name
             external_id: External system identifier
             parent: UUID of the parent work item
-            state: UUID of the state
+            state: UUID of the state (also sent as state_id for CE compatibility)
             estimate_point: Estimate point value
             type: Work item type identifier
 
@@ -241,7 +261,8 @@ def create_work_item(
             priority if priority in get_args(PriorityEnum) else None  # type: ignore[assignment]
         )
 
-        data = CreateWorkItem(
+        # Mirror state onto state_id so Cloud and self-hosted CE both apply it (#183).
+        data = _CreateWorkItemCompat(
             name=name,
             assignees=assignees,
             labels=labels,
@@ -257,6 +278,7 @@ def create_work_item(
             external_id=external_id,
             parent=parent,
             state=state,
+            state_id=state,
             estimate_point=estimate_point,
             type=type,
         )
@@ -411,7 +433,7 @@ def update_work_item(
             external_source: External system source name
             external_id: External system identifier
             parent: UUID of the parent work item
-            state: UUID of the state
+            state: UUID of the state (also sent as state_id for CE compatibility)
             estimate_point: Estimate point value
             type: Work item type identifier
 
@@ -424,7 +446,8 @@ def update_work_item(
             priority if priority in get_args(PriorityEnum) else None  # type: ignore[assignment]
         )
 
-        data = UpdateWorkItem(
+        # Mirror state onto state_id so Cloud and self-hosted CE both apply it (#183).
+        data = _UpdateWorkItemCompat(
             name=name,
             assignees=assignees,
             labels=labels,
@@ -440,6 +463,7 @@ def update_work_item(
             external_id=external_id,
             parent=parent,
             state=state,
+            state_id=state,
             estimate_point=estimate_point,
             type=type,
         )
diff --git a/tests/test_work_item_state_compat.py b/tests/test_work_item_state_compat.py
new file mode 100644
index 00000000..1ac54b08
--- /dev/null
+++ b/tests/test_work_item_state_compat.py
@@ -0,0 +1,78 @@
+"""Unit tests for work item state field Cloud/CE compatibility (#183)."""
+
+import asyncio
+from unittest.mock import MagicMock, patch
+
+from fastmcp import FastMCP
+from plane.models.work_items import WorkItem
+
+from plane_mcp.tools.work_items import (
+    _CreateWorkItemCompat,
+    _UpdateWorkItemCompat,
+    register_work_item_tools,
+)
+
+STATE_UUID = "ba5e07a3-b2a0-4d45-93bf-8b03b0593e13"
+PROJECT_ID = "7ac2e2c6-6057-43e9-88af-59cbda15d1cd"
+WORK_ITEM_ID = "7d61d6dc-8998-409d-b026-6765fc0a7df8"
+
+
+def test_update_compat_emits_state_and_state_id():
+    data = _UpdateWorkItemCompat(state=STATE_UUID, state_id=STATE_UUID)
+    payload = data.model_dump(exclude_none=True)
+    assert payload["state"] == STATE_UUID
+    assert payload["state_id"] == STATE_UUID
+
+
+def test_create_compat_emits_state_and_state_id():
+    data = _CreateWorkItemCompat(name="Task", state=STATE_UUID, state_id=STATE_UUID)
+    payload = data.model_dump(exclude_none=True)
+    assert payload["name"] == "Task"
+    assert payload["state"] == STATE_UUID
+    assert payload["state_id"] == STATE_UUID
+
+
+def test_update_compat_omits_state_fields_when_unset():
+    data = _UpdateWorkItemCompat(name="Renamed")
+    payload = data.model_dump(exclude_none=True)
+    assert payload == {"name": "Renamed"}
+    assert "state" not in payload
+    assert "state_id" not in payload
+
+
+def _tool_fn(mcp: FastMCP, name: str):
+    return asyncio.run(mcp.get_tool(name)).fn
+
+
+def test_update_work_item_tool_passes_dual_state_fields():
+    mcp = FastMCP("test")
+    register_work_item_tools(mcp)
+    update_work_item = _tool_fn(mcp, "update_work_item")
+
+    mock_client = MagicMock()
+    mock_client.work_items.update.return_value = WorkItem(id=WORK_ITEM_ID, name="Task", state=STATE_UUID)
+
+    with patch("plane_mcp.tools.work_items.get_plane_client_context", return_value=(mock_client, "homelab-ops")):
+        update_work_item(project_id=PROJECT_ID, work_item_id=WORK_ITEM_ID, state=STATE_UUID)
+
+    kwargs = mock_client.work_items.update.call_args.kwargs
+    payload = kwargs["data"].model_dump(exclude_none=True)
+    assert payload["state"] == STATE_UUID
+    assert payload["state_id"] == STATE_UUID
+
+
+def test_create_work_item_tool_passes_dual_state_fields():
+    mcp = FastMCP("test")
+    register_work_item_tools(mcp)
+    create_work_item = _tool_fn(mcp, "create_work_item")
+
+    mock_client = MagicMock()
+    mock_client.work_items.create.return_value = WorkItem(id=WORK_ITEM_ID, name="Task", state=STATE_UUID)
+
+    with patch("plane_mcp.tools.work_items.get_plane_client_context", return_value=(mock_client, "homelab-ops")):
+        create_work_item(project_id=PROJECT_ID, name="Task", state=STATE_UUID)
+
+    kwargs = mock_client.work_items.create.call_args.kwargs
+    payload = kwargs["data"].model_dump(exclude_none=True)
+    assert payload["state"] == STATE_UUID
+    assert payload["state_id"] == STATE_UUID