Working paper / 2026
Conversational AI LLM Bench
Abstract
We define conversational AI LLMs as the language models at the center of cascaded voice pipelines, between speech recognition and speech synthesis, that return a first token within one second: a median time to first token of 1,000 ms or less. The Conversational AI LLM Bench (CALLM) benchmarks this category. Each model operates every agent of a multi-agent front desk in healthcare, legal, and customer support, with production-length prompts, executable tools, and per-call database state. A simulated caller pursues a locked task over a simulated phone line, so the model receives only what a speech recognizer would have transcribed, errors included. A deterministic verifier scores tool calls, handoffs, and final database state; pass@1 and pass5 measure single-attempt capability and five-attempt reliability.
Clone the repository, point a model at an industry pack, and reproduce the evaluation environment.
Meta's open-weights Llama 3.3 70B instruct model.
| Scope | pass^5 | pass@1 | E / M / H | Tools | Handoff | Final DB | TTFT | Cost/hr |
|---|---|---|---|---|---|---|---|---|
| Cross-industry | 15.0% | 27.2% | 74 / 21 / 10 | 28.1% | 56.4% | 45.2% | 896ms | $2.02 |
| Healthcare | 21.7% | 28.0% | 88 / 25 / 1 | 28.0% | 64.0% | 53.7% | 903ms | $2.76 |
| Legal | 5.0% | 32.7% | 38 / 37 / 26 | 33.0% | 76.0% | 55.7% | 887ms | $1.07 |
| Customer support | 18.3% | 21.0% | 97 / 0 / 4 | 23.3% | 29.3% | 26.3% | 896ms | $2.23 |
E / M / H is pass@1 on easy, medium, and hard tasks. Gate columns are the share of conversations that cleared each check.