Hopper
ChatGPT pluginVoice AI inference for agents
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Developer tools589th of 638 by placement
| # | Plugin | Position | 7d |
|---|---|---|---|
| 587 | #6713 | — | |
| 588 | #6721 | — | |
| 589 | #6723 | — | |
| 590 | #6736 | — | |
| 591 | #6739 | — |
Hopper serves open-source models for real-time voice agents: a low-latency LLM behind a standard chat-completions API, plus text-to-speech and speech-to-text. Hopper speaks text with an inline audio player, transcribes recordings you attach (WAV, MP3, M4A, Ogg, FLAC or WebM) with word timestamps, lists models and prices, returns tested integration code for popular voice-agent frameworks, and reviews a voice agent's prompt, tools and client code for what delays its first reply. After you sign in with your Hopper account, it shows your usage and creates API keys. Where it can run commands in your project, the plugin also sets Hopper up in a voice-agent codebase: it measures time to first token on the agent's own system prompt and tools in a 10-turn simulated call and shows the results before changing any code, and after you say go it switches only the LLM. Text and audio you send go to Hopper's API; see withhopper.com/privacy.
Example prompts
- “Make my voice agent respond faster with Hopper”
- “Why does my voice agent pause before answering?”
- “Say "Thanks for calling, how can I help?" in a Hopper voice”
Skills
hopper-benchmark
Measure a voice agent's LLM time to first token on Hopper with its own system prompt and tools over a simulated 10-turn call, and report first-turn and later-turn latency and the prompt-cache hit rate. Changes no code. Use when the user asks "how fast would my agent be on Hopper", "benchmark TTFT", "is prompt caching working" or wants before/after numbers. Not for STT/TTS latency or load tests; to switch the agent to Hopper, use hopper-integrate.
hopper-diagnose
Find what delays a voice agent's first spoken word: timestamps or IDs at the top of the prompt, a new client per call, HTTP/1.1, no warm-up, thinking left on, tools named but not sent. Ranks fixes by the latency they recover. Works with any LLM provider, needs no key, and edits nothing until the user picks fixes. Use when the user reports "long pauses", "dead air", "the first reply is slow" or asks for a latency review of a voice agent.
hopper-integrate
Switch an existing voice agent's LLM to Hopper, an OpenAI-compatible endpoint built for low time to first token. Gets a key for the project with no human step, benchmarks the agent's own prompt and tools, and edits code only after the user says go. Use when the user says "make my agent respond faster", "set up Hopper", "try Hopper" or "swap the LLM" in a Pipecat, LiveKit Agents, Vapi or OpenAI-SDK voice agent. For numbers only, use hopper-benchmark; to find what's slow, use hopper-diagnose.
hopper-speak
Turn text into speech with Hopper text-to-speech: play it aloud, save a WAV file, or preview and pick a voice. Needs no setup: the first use registers a key for the agent itself. Use when the user says "read this aloud", "say this out loud", "generate a voiceover", "make an audio file of…", "TTS" or "which voice should I use". Not for writing a speech (plain text), transcribing audio (hopper-transcribe) or a voice agent's LLM (hopper-integrate).
hopper-transcribe
Transcribe speech in an audio or video file with Hopper speech-to-text, with word timestamps. Takes WAV, MP3, M4A, voice memos and video (decoded with ffmpeg). Needs no setup: the first use registers a key for the agent itself. Use when the user says "transcribe this", "what does this recording say", "speech to text", "STT", "summarize this call" or "caption this". Not for generating audio (hopper-speak) or measuring LLM latency (hopper-benchmark).
- Categories
- Sign-in
- On Install
- Capabilities
- Interactive, Read, Write
- Availability
- Available
- Version
- 1.2.3
- Keywords
- voice agents, voice ai, llm, inference, latency, ttft, prompt caching, pipecat, livekit, vapi, openai-compatible, gemma, text to speech, speech to text, tts, stt, transcription
- Created
- October 2, 2026
- More info
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