Add local voice model transcription

[pdufour]

Description

This adds the ability to do transcription using a local LLM model for the in-development transcription
There are already some ways to load local models (i.e. you can run with ollama using --local-provider ollama) so this extends that theme with the ability to also do transcription locally. It can be useful for instance if you are temporarily offline.

output.mp4

Specific Changes

• Add new /voicemodel slash command that lets you switch between remote transcription and local
• Change space to record to use above model section for transcription
• Add ability to download models on the fly with hf_hub

Test Plan

Test recording with onnx model

• Add voice-input feature
• Edit codex-rs/tui/BUILD.bazel
• Add in crate_features voice-input like so:

codex_rust_crate(
    name = "tui",
    crate_name = "codex_tui",
    crate_features = ["voice-input"],

• Run the app with the voice transcription active:

RUST_LOG=error,transcribe_rs=debug,codex_tui::voice=debug bazel run //codex-rs/cli:codex -- --enable voice_transcription --enable realtime_conversation

• Select a voice-model:

/voice-model

• Select Parakeet
• Look at logs in another terminal:

tail -f ~/.codex/log/codex-tui.log

• Hold down space and record something
• See the transcription come through and see that it used Parakeet
• Verify the logs

2026-03-16T00:59:43.065655Z DEBUG codex_tui::voice: transcribe_bytes route: parakeet

Test recording with remote openai selection

• Repeat same steps but select openai model (this is already the default)
• Hold down space and record something
• See the transcription come through and see that it used OpenAI:

Verify the logs:

2026-03-16T00:59:43.065655Z DEBUG codex_tui::voice: transcribe_bytes route: openai

Test recording with no voice-model selected

• Repeat above steps but don't go to the /voice-model input
• See that it selects openai when you record (view logs)
• View logs and see openai logs

2026-03-16T00:59:43.065655Z DEBUG codex_tui::voice: transcribe_bytes route: openai