Feature Request: Plugin hook for filtering session list in /sessions dialog #9553

Design: Session Filtering Hook for Plugin Integration

Goal

Allow plugins to control which sessions appear in the /sessions dialog by returning a filtered list of session IDs.

API Surface

New Plugin Hook

• session.list.filter(input, output)
  • Input: { projectID, directory, sessionID? }
  • Output: { sessionIDs? }
  • Behavior: If sessionIDs is provided, the UI should only display those sessions. If not provided, the UI shows all sessions.

New Server Endpoint

• GET /session/filter?sessionID=...
  • Invokes the hook and returns { sessionIDs? }
  • Tied to current Instance.project.id and Instance.directory

Data Flow

1. /sessions dialog opens in TUI.
2. TUI requests /session/filter using the SDK internal client (so it runs through Server.App().fetch).
3. Server triggers session.list.filter hook.
4. Plugin returns sessionIDs to display.
5. TUI filters the session list to those IDs.

TUI Behavior

• If hook returns sessionIDs, filter the list with a set lookup.
• If hook returns nothing, show all sessions (current behavior).

Backward Compatibility

• If no plugin implements the hook, session list remains unchanged.
• No behavior change for existing sessions or storage formats.

Files Touched (opencode)

• packages/plugin/src/index.ts — hook type definition
• packages/opencode/src/server/routes/session.ts — filter endpoint
• packages/opencode/src/cli/cmd/tui/component/dialog-session-list.tsx — request + UI filtering