[Feature Request] Add writable MCP tool to assign sessions to sidebar groups

Feature request: let automation assign a session to a sidebar group

Product: Claude Code desktop app (macOS, app 1.40609.1 / claude-code 2.1.255)

Problem

I organize sessions with custom sidebar groups that model my workflow state:
작업 중 (in progress) → 작업 완료 (done) → 리뷰 중 (reviewing) → 리뷰 완료 (review done) → 리뷰 검증/반영 (applying review feedback).

Every new session has to be dragged into the right group by hand, and dragged again on every
state change. With 20+ concurrent sessions this is constant manual bookkeeping, and the state is
almost always derivable (branch name, worktree, which skill is running).

Current state (what I verified)

• The MCP session tools (get_session, list_sessions) expose group read-only.

There is no way to set it.

• Groups and assignments are persisted in

~/Library/Application Support/Claude/claude_desktop_config.json
under preferences.epitaxyPrefs.dframe-group-scopes.<scope>.{groups, assignments},
where assignments map code:<hostSessionId> → <groupId>.

• Editing that file while the app runs does not work: the app holds the state in memory and

rewrote my edit within ~30 seconds.

• set_session_title is writable and applies live, so title-based status prefixes are the

only workaround — but they don't move sessions between groups.

Requested

1. A writable counterpart to the read-only group field, e.g.

mcp__ccd_session_mgmt__set_session_group({ session_id: "self" | <id>, group: <name|id> }),
optionally creating the group if it does not exist.

1. Ideally also settable from a hook, since CLAUDE_CODE_HOST_SESSION_ID (e.g.

local_2d66c0a2-…) is already in the hook environment — a SessionStart hook could file a
session into the right group with zero model round-trips.

Why it matters

Sidebar groups are the only workflow-state UI in the app, but they are the one piece of session
metadata that automation cannot touch. Titles, archiving, and messaging are all scriptable;
grouping is not. Making it writable would let skills move a session to 리뷰 중 when a review
starts and to 작업 완료 when a PR is opened, which is exactly the bookkeeping the groups exist for.