This isn’t actually a regression, and Composer 2.5 still has AskQuestion. The limitation you linked (Composer not using AskQuestion) was fixed back in April, so Composer 2.5 shows the structured picker normally in Agent mode now.
What you’re hitting is a different model. The structured AskQuestion picker is currently turned off for Grok 4.5, and Auto can route to it. When that happens, the model asks clarifying questions inline as plain text instead of showing the popup. This is intentional for now (not a quota issue, which is why remaining quota doesn’t bring it back), and it applies in every mode for Grok 4.5, so Plan mode alone won’t restore it while Grok is the model in use.
The reliable fix is what you already found: pick a specific model instead of Auto. Composer 2.5, Claude, or GPT in Agent mode all show the AskQuestion popup normally.
We do plan to bring AskQuestion back for Grok 4.5, but there’s no ETA to share yet. A few others are tracking it here: Grok 4.5 cannot use AskQuestion tool; falls back to inline questions (Composer 2.5 works)