Elicitation: First highlighted option not actually selected — submitting immediately gives 'field is missing'

[m-nash]

Problem

When an MCP elicitation renders an enum field with multiple choices, the first option appears visually highlighted/selected by default. However, if the user immediately presses Ctrl+S (or Enter, now that #1863 is fixed) without first navigating away and back, the submission fails with a "a field is missing" error.

Workaround

To select the first (already-highlighted) option, the user must:

1. Press ↓ (arrow down) to move to a different option
2. Press Enter to select it
3. Press ↑ (arrow up) back to the first option
4. Press Ctrl+S / Enter to submit

This defeats the purpose of having the first option pre-highlighted — it should already count as selected.

Expected Behavior

If the first option is visually highlighted by default, submitting the form immediately (via Ctrl+S or Enter) should select that first option without requiring the user to manually navigate to it first.

Related

• Elicitation: Allow Enter key to submit forms, not just Ctrl+S #1863 — Enter key now submits elicitation forms (fixed). With that fix in place, pressing Enter alone on the pre-highlighted first option should just work.

Environment

• Copilot CLI v0.0.422
• Windows, PowerShell
• MCP elicitation with TitledSingleSelectEnumSchema (C# SDK v1.0.0)