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.agents/skills/speech/references/audio-api.md

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+# Audio Speech API quick reference
+
+## Endpoint
+- Create speech: `POST /v1/audio/speech`
+
+## Default model
+- `gpt-4o-mini-tts-2025-12-15`
+
+## Other speech models (if requested)
+- `gpt-4o-mini-tts`
+- `tts-1`
+- `tts-1-hd`
+
+## Core parameters
+- `model`: speech model
+- `input`: text to synthesize (max 4096 characters)
+- `voice`: built-in voice name
+- `instructions`: optional style directions (not supported for `tts-1` or `tts-1-hd`)
+- `response_format`: `mp3`, `opus`, `aac`, `flac`, `wav`, or `pcm`
+- `speed`: 0.25 to 4.0
+
+## Built-in voices
+- `alloy`, `ash`, `ballad`, `cedar`, `coral`, `echo`, `fable`, `marin`, `nova`, `onyx`, `sage`, `shimmer`, `verse`
+
+## Output notes
+- Default format is `mp3`.
+- `pcm` is raw 24 kHz 16-bit little-endian samples (no header).
+- `wav` includes a header (better for quick playback).
+
+## Compliance note
+- Provide a clear disclosure that the voice is AI-generated.