🤖 Simplify state: derive projects from workspace metadata

[ammar-agent]

Problem

Currently we maintain two sources of truth for workspace lists:

1. workspaceMetadata Map - updated via metadata events from backend
2. projects Map - manually reloaded when workspaces change

This requires careful coordination to keep them in sync. Recent bug: forked workspace didn't appear in sidebar until we added special "detect new workspace" logic.

Proposed Solution

Derive projects from workspace metadata. All information in ProjectConfig exists in WorkspaceMetadata:

function deriveProjectsFromMetadata(
  workspaceMetadata: Map<string, FrontendWorkspaceMetadata>
): Map<string, ProjectConfig> {
  const projects = new Map<string, ProjectConfig>();
  
  for (const metadata of workspaceMetadata.values()) {
    if (!projects.has(metadata.projectPath)) {
      projects.set(metadata.projectPath, {
        path: metadata.projectPath,
        workspaces: [],
      });
    }
    
    projects.get(metadata.projectPath)!.workspaces.push({
      path: metadata.namedWorkspacePath,
      id: metadata.id,
      name: metadata.name,
      createdAt: metadata.createdAt,
    });
  }
  
  return projects;
}

Benefits

• ✅ Single source of truth (workspaceMetadata)
• ✅ Projects always in sync (derived on-demand)
• ✅ Eliminates entire class of synchronization bugs
• ✅ ~155 LoC reduction (remove useProjectManagement, manual reloading)
• ✅ Simpler mental model

Implementation

Phase 1: Add derivation

1. Create src/utils/deriveProjects.ts
2. Use in App.tsx: const projects = useMemo(() => deriveProjectsFromMetadata(workspaceMetadata), [workspaceMetadata])
3. Verify UI works identically

Phase 2: Remove dead code

1. Delete useProjectManagement hook
2. Remove onProjectsUpdate callback machinery
3. Remove manual project reloading from create/remove/rename
4. Remove "detect new workspace" logic (lines 58-75 in useWorkspaceManagement.ts)

Phase 3: Update tests

• Update tests to use derivation
• Document pattern

Unresolved: Empty Projects

Current behavior: Config can have projects with no workspaces, shown in sidebar
New behavior: Projects only appear when they have ≥1 workspace

Question: Is this acceptable?

Arguments for yes:

• Empty projects have no actions, just take space
• Creating first workspace brings project back
• Cleaner UX (only show active projects)

Arguments for no:

• User adds project, expects to see it immediately
• Breaks expectation that "added = visible"

Recommendation: Try it, see if users complain. Empty projects are edge case.

Alternative: Keep Project Registration

If empty projects must be visible:

• Keep project list in config as projects: ['/path/to/project'] (just paths)
• Derive workspaces from metadata
• Show project if in list OR has workspaces
• Smaller win (~80 LoC instead of ~155 LoC) but still valuable

Estimated Effort

1-2 hours, mostly deleting code. Low risk (type system catches issues).

Related

• Current workaround: useWorkspaceManagement detects new workspaces and triggers reload (lines 58-75)
• This issue proposes eliminating the root cause instead of patching symptoms

Generated with cmux

[ammario]

Note: showing empty project is a requirement, but I still think we should derive all state from a single IPC handler.