AskUserQuestion tool closes the panel/screen when used via claude-agent-acp in Zed (Windows + macOS)

Description

When Claude Code invokes the AskUserQuestion tool while running inside Zed (via the claude-agent-acp ACP integration), the panel/screen showing the interactive question closes instead of presenting the question to the user. This has been observed on both Windows and macOS, so it does not appear to be OS-specific.

From the agent's side, this surfaces as a tool-call rejection (as if the user had explicitly declined the tool use), even though the user never actually got to see or respond to the question. The agent has no way to distinguish "user declined" from "UI failed to render," so it silently treats a UI failure as an explicit decision.

Filed in parallel on the Zed side as zed-industries/zed#61984, since it's not yet clear whether the root cause is in Zed's ACP client handling or in how claude-agent-acp sends the AskUserQuestion elicitation request.

Reproduction steps

1. Open a project in Zed with the Claude Code agent (claude-acp) integration enabled.
2. Ask Claude Code to perform a task that leads it to call the AskUserQuestion tool (e.g., asking it to choose between two implementation approaches, or confirm a risky/ambiguous action).
3. Observe that the panel/screen presenting the question closes instead of showing the selectable options.

Expected behavior

The question panel should render with the provided options and wait for the user to select one (or provide free text), the same as it would in the Claude Code CLI/terminal.

Actual behavior

The panel or screen closes without showing the options, on both Windows and macOS.

Environment

• Integration: Claude Code via ACP, using Zed's bundled agent registry entry claude-acp
• Resolved package: @agentclientprotocol/claude-agent-acp@0.64.0 (latest on npm as of 2026-07-30)
• Editor: Zed 1.13.1 (build 20260729.151724) — confirmed latest via Zed's "Check for Updates", macOS (Darwin 25.6.0)
• Also reproduces on Windows (version details not captured at time of original report there)

Root cause

Not confirmed. No crash log/stack trace has been captured yet from either side at the moment the panel closes. Both Zed and claude-agent-acp were on their latest respective versions at the time of the most recent reproduction, so this doesn't look like a simple outdated-software issue.

Impact

• Users lose the ability to use structured multiple-choice confirmations at all inside Zed.
• Current workaround: instructing Claude Code (via project memory/instructions) to never call AskUserQuestion and to confirm everything via plain text instead.