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.
Anthropic's previous Haiku model.
| Scope | pass^5 | pass@1 | E / M / H | Tools | Handoff | Final DB | TTFT | Cost/hr |
|---|---|---|---|---|---|---|---|---|
| Cross-industry | 36.7% | 65.0% | 79 / 64 / 59 | 65.7% | 92.4% | 87.7% | 459ms | $1.34 |
| Healthcare | 30.0% | 54.7% | 92 / 58 / 33 | 54.7% | 91.7% | 89.3% | 460ms | $1.43 |
| Legal | 35.0% | 73.3% | 77 / 71 / 74 | 73.7% | 92.7% | 79.0% | 454ms | $1.12 |
| Customer support | 45.0% | 67.0% | 70 / 64 / 68 | 68.7% | 92.7% | 94.7% | 464ms | $1.47 |
E / M / H is pass@1 on easy, medium, and hard tasks. Gate columns are the share of conversations that cleared each check.