New 'Prompt suggestions' feature predicts and can pre-fill your next prompt

What

• A new setting, "Prompt suggestions" (promptSuggestionEnabled), lets Claude Code generate a predicted next prompt after each turn and either suggest it to you or fill it directly into the input box.
• The input draft controller gained fillDraft and suggestDraft methods that write or propose this suggested text, setting a promptSuggestion state (status: 'generated', the suggested text, and a generation request ID) once a turn ends — but only when the input box is empty and no dialog is open.
• Plugins gained two new corresponding actions, prompt.fill and prompt.suggest, added to the plugin action-dispatch table alongside existing actions like prompt.submit, tool.call, agent.spawn, and ui.ask, each with their own budget tracking, letting a plugin programmatically fill the prompt box or suggest text to the user.
• A session-config field promptSuggestions and a telemetry event description ("Predicted next user prompt, emitted after each turn when promptSuggestions is enabled") back the feature.

Why This gives Claude Code the ability to proactively suggest what you might want to type next, saving time on repetitive or predictable follow-up prompts, and gives plugins a supported way to drive the same behavior.