Bug: update_work_item state is silently ignored on self-hosted CE (inverse of state_id→state rename)

Problem

update_work_item (and likely create_work_item) accept a state parameter and the official MCP/plane_sdk serialize it as "state" in the PATCH/POST body. On some Plane deployments that works; on others — including self-hosted Plane Community Edition — the REST API expects "state_id" instead.

When the wrong field name is sent, Plane returns HTTP 200 with an updated updated_at, but the work item's state is unchanged. Agents treat this as success and loop or invent wrong explanations (workflow constraints, parent blocking, etc.).

This is the inverse of the field-name mismatch fixed in community forks such as ZethicTech/plane-mcp-server#13 / #14, which renamed state_id → state for API compatibility. That direction fixes Cloud-style APIs but reintroduces a silent no-op on CE instances that only honor state_id.

Reproduction (self-hosted Plane CE)

Against a self-hosted instance (workspace homelab-ops, MCP plane_mcp_server 0.2.10 / plane_sdk 0.2.19):

1. Call MCP update_work_item with a valid full state UUID:

   {
     "project_id": "<project-uuid>",
     "work_item_id": "<work-item-uuid>",
     "state": "ba5e07a3-b2a0-4d45-93bf-8b03b0593e13"
   }
   

2. MCP reports success; response still shows the previous state (e.g. Todo).
3. Same PATCH via the REST API:

Endpoints tested (both behave the same for this field):

• PATCH /api/v1/workspaces/<slug>/projects/<id>/issues/<id>/
• PATCH /api/v1/workspaces/<slug>/projects/<id>/work-items/<id>/

Comments and other updates via MCP work fine on the same token — this is isolated to the state field name.

Root Cause

UpdateWorkItem in plane_sdk exposes state: str | None and serializes that key as "state". The MCP tool mirrors that parameter name. Plane CE's issue/work-item update handler appears to read "state_id" and ignore unknown/extra "state" without erroring.

Cloud (and forks that followed #13-style renames) expect "state". So a single-field rename in either direction breaks the other target.

Suggested Fix

Send both fields when a state UUID is provided, e.g.:

{
  "state": "<uuid>",
  "state_id": "<uuid>"
}

That should satisfy both Cloud (state) and CE (state_id) without version sniffing. Same pattern is worth considering for any other id/rename pairs that have flipped between API generations (parent / parent_id, etc.) if those show the same silent-ignore behavior.

Alternatively: document which field each Plane edition accepts and branch in the SDK — dual-send is simpler and avoids another silent-break cycle.

Impact

Agent clients (Hermes, Cursor, Claude, etc.) cannot reliably move work items between states via official MCP on self-hosted CE. Reads/list/comments succeed; only state transitions fail silently.

Start with the UpdateWorkItem SDK model and the MCP update_work_item tool, which the issue identifies as serializing the state field. Reproduce the PATCH behavior against the listed issue and work-item endpoints, then verify that state updates work on both CE and Cloud-style APIs without changing other fields.