[BUG] Quick Entry overlay fails with `custom_3p_not_available` in Bedrock mode (Desktop app)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The Quick Entry overlay (Option double-tap / native overlay) opens correctly in 3P/Bedrock mode, but submitting a prompt always fails with a 503 custom_3p_not_available error. The overlay routes submissions to the claude.ai Chat API (/api/organizations/.../chat_conversations/.../completion) instead of the local Cowork/Code session that already works with Bedrock.

The supported-features-info.json shows nativeQuickEntry: "supported", quickEntryGlobalShortcut: "supported", and chatIn3p: "supported" — so the feature flags are enabled, but the submission code path doesn't handle 3P mode. The overlay opens and accepts input, but the backend it targets (claude.ai API) explicitly rejects 3P sessions.

What Should Happen?

Quick Entry should route the submission through the local Cowork/Code backend (which already works with Bedrock), creating a new Cowork session — the same way a prompt typed directly in the Code tab works.

Error Messages/Logs

Steps to Reproduce

1. Configure Claude Desktop with Bedrock as the 3P provider (enterprise config with CLAUDE_CODE_USE_BEDROCK=1)
2. Open the app — the Cowork/Code tab works correctly with Bedrock
3. Trigger Quick Entry via Option double-tap (or custom global shortcut)
4. Type a prompt and submit
5. Submission fails silently; no response is generated

Note: The overlay opens fine, the issue is purely that the submission routes to the wrong backend.

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.177 (Claude Code CLI) / Claude Desktop 1.13576.0

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Other

Additional Information

This is a Desktop app issue, not a terminal/CLI issue. The Terminal/Shell field is not applicable — the bug is in the Quick Entry overlay of the Claude Desktop app (Electron).

Environment details

• macOS: 15.5 (Darwin 25.5.0), Apple M5, arm64
• Provider: Amazon Bedrock via enterprise config with custom credential helper (~/.claude/aws-gitlab-auth)
• Auth: CLAUDE_CODE_USE_BEDROCK=1 with AWS credentials

Root cause analysis

From supported-features-info.json, these flags are all "supported":

• nativeQuickEntry
• quickEntryGlobalShortcut
• quickEntryDictation
• chatIn3p

The overlay opens fine. The problem is purely routing: Quick Entry submits to the Chat surface (claude.ai API at /api/.../chat_conversations/.../completion), which rejects requests in 3P mode. Meanwhile, the Cowork/Code tab works perfectly with Bedrock because it routes through the local Claude Code process.

Suggested fix

In 3P mode, Quick Entry submissions should route to a local Cowork session (same backend as the Code tab) instead of the claude.ai chat API.