Salvage merged via PR #23273 (rebase) — your commit shipped on main with your authorship preserved. AUTHOR_MAP entry already existed.

The DB-layer validation approach you took was the right call — it catches the bug at every entry point (CLI, dashboard POST, kanban_create tool, future REST/MCP) instead of needing a per-tool guard. The get_toolset_names() registry lookup is also better than hardcoding the list.

One small follow-up improvement during salvage: the loop now aggregates ALL toolset names found into a single error rather than raising on the first. Agents that confuse skills with toolsets usually pass several at once (skills=["web", "browser", "terminal"]), and listing only the first mistake forces serial fix-then-retry. Plus the error message now explicitly names the toolsets: YAML key and gives concrete examples of both categories so the conceptual gap closes.

Thanks @LeonSGP43!
#23273