[FEATURE] /voice: Add audio input device selection

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Problem:
Bluetooth headphones (e.g. Sony WH-1000XM4) have two profiles:

• A2DP — high quality audio output, no microphone
• Hands-Free (HFP) — lower quality audio with microphone

Users intentionally keep A2DP as default to avoid degraded audio quality. Apps like Discord and browsers automatically switch to HFP when microphone access is needed, or allow selecting the input device
manually.

Claude Code does neither — it only reads the system default input, resulting in "No audio detected from microphone" error.

Expected behavior:

• Allow selecting an audio input device via config (/config) or a prompt when starting /voice
• Or: automatically activate the HFP profile when /voice is started, similar to how Discord/browsers handle this

Environment:

• Windows 11
• Bluetooth headphones (Sony WH-1000XM4)
• Microphone works in Discord and browser voice chats

Proposed Solution

Add an audio input device selection option to /voice mode. Possible implementations (in order of preference):

1. Interactive device picker — when starting /voice, show a list of available input devices and let the user choose (similar to Discord's voice settings)
2. Config option — add voiceInputDevice to settings.json so users can set their preferred microphone once via /config
3. Auto-profile switching — detect Bluetooth HFP devices and activate the microphone profile automatically when /voice starts, restore A2DP when /voice ends

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

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