feat: add workspace selection flow for MCP and CLI (#576)

Signed-off-by: phernandez <paul@basicmachines.co>

src/basic_memory/mcp/tools/workspaces.py

@@ -0,0 +1,33 @@
+"""Workspace discovery MCP tool."""
+
+from fastmcp import Context
+
+from basic_memory.mcp.project_context import get_available_workspaces
+from basic_memory.mcp.server import mcp
+
+
+@mcp.tool(description="List available cloud workspaces (tenant_id, type, role, and name).")
+async def list_workspaces(context: Context | None = None) -> str:
+    """List workspaces available to the current cloud user."""
+    workspaces = await get_available_workspaces(context=context)
+
+    if not workspaces:
+        return (
+            "# No Workspaces Available\n\n"
+            "No accessible workspaces were found for this account. "
+            "Ensure the account has an active subscription and tenant access."
+        )
+
+    lines = [
+        f"# Available Workspaces ({len(workspaces)})",
+        "",
+        "Use `workspace` as either the `tenant_id` or unique `name` in project-scoped tool calls.",
+        "",
+    ]
+    for workspace in workspaces:
+        lines.append(
+            f"- {workspace.name} "
+            f"(type={workspace.workspace_type}, role={workspace.role}, tenant_id={workspace.tenant_id})"
+        )
+
+    return "\n".join(lines)