gpt-realtime-expert

name: gpt-realtime-expert description: Expert guidance for implementing OpenAI gpt-realtime-1.5, including WebRTC, WebSocket, and SIP configurations. confidence: high

gpt-realtime-1.5 Expertise

You are an expert in the OpenAI Realtime API (gpt-realtime-1.5).

Model Capabilities

• Low Latency: Optimized for speech-to-speech with ~32k input and 4k output tokens.
• Modality: Supports Text, Audio, and Image input; Text and Audio output.
• Features: Enhanced tool calling, multilingual accuracy, and natural prosody.

Implementation Standards

• Prefer WebRTC for browser-based low-latency audio.
• Use WebSockets for server-side middle-tier applications.
• When handling audio deltas, use the updated event paths: response.output_audio.delta.
• Always implement VAD (Voice Activity Detection) for natural turn-taking.

System Prompt Best Practices

• Use ALL CAPS for emphasis on critical instructions (NEVER, ALWAYS, ONLY).
• Use bulleted format organized into named sections — NEVER dense paragraphs.
• Add variety rules with example phrases to prevent robotic repetition.
• Add explicit grounding rules ("ONLY recommend items found in search results") to prevent hallucination.
• Keep prompts tight — long prompts increase first-response latency.

VAD Tuning Guidelines

• Threshold 0.7 for quiet demo/office environments with echo suppression active.
• Threshold 0.8 for noisy environments or when echo suppression is incomplete.
• prefix_padding_ms: 300 minimum — 200ms clips plosive consonants.
• silence_duration_ms: 500 is optimal for conversational ordering flows.
• Always re-tune VAD threshold after adding/changing echo suppression — they interact.

Echo Suppression Pattern (Middle-Tier WebSocket)

• Track ai_speaking flag: set on response.audio.delta, clear on response.audio.done.
• Apply cooldown (300ms) after AI stops speaking before accepting user audio.
• Send input_audio_buffer.clear after AI finishes to flush echoed audio.
• Reset suppression on input_audio_buffer.speech_started to preserve barge-in.
• Use substring checks (not JSON parse) for performance on the audio hot path.

Critical Constraints

• Use all caps for emphasis in system prompts for this model.
• Use bullets over paragraphs for better instruction following.
• Avoid robotic repetition by adding "variety rules" in the session configuration.
• Use a pleasant and quick-serve restaurant drive-thru friendly voice.