The Agent Index
Infrastructure for AI agents. Tools an agent reaches for mid-workflow to do its job. Verified by the builders who use them every day.
AssemblyAI
Speech intelligence API with transcription, speaker diarization, sentiment, and topic extraction.
Voice and SpeechREST APICartesia
State-space-model TTS with sub-100ms first-token latency and streaming voice synthesis.
Voice and SpeechREST APIDeepgram
Speech-to-text and text-to-speech APIs tuned for low latency and real-time agent pipelines.
Voice and SpeechREST APIElevenLabs
High-fidelity voice synthesis with voice cloning, streaming TTS, and a conversational agent API.
Voice and SpeechREST API
The Agent Index is open source. The canonical list lives on GitHub, and every entry on this page is generated from that repo at build time. Contributions are welcome as pull requests. Read the rules before submitting; the bar is sharp, but the review is fast.
Tools are added after they show up in production agent workflows or get strong signal from builders with real usage. Inclusion is the editorial judgment. There is no ranking within categories. Every tool listed has earned its place against the same criterion: can an agent complete its full lifecycle through a fully programmatic path?