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.
Healthcare / C5-H1
What this task measures
The caller is on the line with Straus Dermatology for one locked request: Large balance, cannot pay in full. They keep repeating that ask through a waitlist offer, a callback, or a different errand. We included it as a hard billing and payments case because balances and payment links have to come from the chart, at the amount on file. The agent succeeds only if it stays on that request, reaches the outcome by following the identity then billing then scheduling path, and leaves the record exactly as this case requires: the right row written or cleared, and nothing extra.
One model at a time, with a representative pass and fail conversation when both exist. GPT-4.1 is the default view.
Conversation cost $0.087
0:00 / 0:00 · scrub · trace sample · click a span to play, drag to scrub, scroll to pan
Audio
Speech Audio
Agent Audio
Handoffs
Tool Calls
Errors
Transcript
How a conversation passes
Combined pass is the logical and of three deterministic gates. Tools, handoff path, and final database state must all pass on the same conversation. One miss fails the call.
Combined
Fail
This sample fails because tools did not match. Combined cannot pass unless every gate does.
Expected versus actual tool calls on this conversation.
Expected
Actual
Parameters
next_intent: billing
next_intent: billing
Output
+ role: identity
+ success: true
Parameters
- dob: 1972-06-30
- first_name: Maria
- last_name: Alvarez
Output
None recorded.
None recorded.
Parameters
dob: 1972-06-30
dob: 1972-06-30
full_name: Maria Alvarez
full_name: Maria Alvarez
Output
+ data: {"verified":true,"patient_id":"pat_maria_alvarez"}+ error_code: empty
+ ok: true
+ patient_safe_message: empty
Parameters
None recorded.
None recorded.
Output
+ data: {"patient_id":"pat_maria_alvarez","name":"Maria Alvarez","language":"en","home_office":"Park Avenue","upcoming_appointments":[{"id":2,"patient_id":"pat_maria_alvarez","location_id":"loc_park_ave","provider_id":"prov_chen","appointment_type_code":"COS_CONSULT","start":"2026-08-21T15:00","end":"2026-08-21T15:30","description":"Botox consult","status":"booked","created_at":"2026-11-11 01:06:12"}],"balance_cents":48000,"insurance":{"carrier":"Cigna","plan_name":"Open Access Plus","member_id_last4":"6778"},"portal_active":false,"open_orders":[],"clinical_flags":[]}+ error_code: empty
+ ok: true
+ patient_safe_message: empty
Parameters
None recorded.
None recorded.
Output
+ role: billing
+ success: true
Parameters
None recorded.
None recorded.
Output
+ data: {"balance_cents":48000,"line_items":[{"line_item_id":"li_noshow","description":"Missed-visit fee","amount_cents":5000},{"line_item_id":"li_visit","description":"Office visit balance","amount_cents":43000}]}+ error_code: empty
+ ok: true
+ patient_safe_message: empty
Parameters
line_item_id: li_visit
line_item_id: li_visit
Output
+ data: {"line_item_id":"li_visit","approved_script":"That charge is the portion of your visit your insurance applied to your deductible or copay after the claim processed."}+ error_code: empty
+ ok: true
+ patient_safe_message: empty
Parameters
None recorded.
None recorded.
Output
+ data: {"eligible":true,"provider":"CareCredit","note":null}+ error_code: empty
+ ok: true
+ patient_safe_message: empty
Parameters
mobile_e164: +12125550133
mobile_e164: +12125550133
Output
+ data: {"sent":true,"channel":"sms","mobile_e164":"+12125550133","amount_cents":null}+ error_code: empty
+ ok: true
+ patient_safe_message: empty
Parameters
None recorded.
None recorded.
Output
+ role: scheduling
+ success: true
Parameters
+ location_id: loc_park_ave
Output
+ data: {"locations":[{"id":"loc_park_ave","name":"Park Avenue","zip":"10016","offers_cosmetic":true,"address":"386 Park Avenue South, New York, NY 10016","floor":"4th floor","suite":"Suite 410","hours":"Mon-Fri 8am-5pm, Sat 9am-1pm","services":"medical, surgical, cosmetic, allergy","transit":"One block from the 6 train at 33rd Street","parking":"Garage next door on East 27th"},{"id":"loc_brooklyn_heights","name":"Brooklyn Heights","zip":"11201","offers_cosmetic":true,"address":"142 Montague Street, Brooklyn, NY 11201","floor":"2nd floor","suite":"Suite 2B","hours":"Mon-Fri 8am-5pm","services":"medical, surgical, cosmetic, allergy","transit":"Two blocks from Borough Hall","parking":"Street parking; garage on Clinton Street"},{"id":"loc_windermere","name":"Windermere","zip":"34786","offers_cosmetic":false,"address":"7600 Conroy Windermere Road, Windermere, FL 34786","floor":"Ground floor","suite":"Suite 100","hours":"Mon-Fri 8am-5pm","services":"medical, surgical, allergy","transit":"No transit nearby","parking":"Free surface lot"}]}+ error_code: empty
+ ok: true
+ patient_safe_message: empty
Parameters
location_ids: ["loc_park_ave"]
location_ids: ["loc_park_ave"]
+ max_results: 3
Output
+ data: {"slots":[{"slot_id":"slot_loc_park_ave_1","location_id":"loc_park_ave","location":"Park Avenue","provider_id":"prov_chen","provider":"Dr. Amy Chen, MD, FAAD","start":"2026-08-24T09:00","end":"2026-08-24T09:30"},{"slot_id":"slot_loc_park_ave_2","location_id":"loc_park_ave","location":"Park Avenue","provider_id":"prov_chen","provider":"Dr. Amy Chen, MD, FAAD","start":"2026-08-25T11:30","end":"2026-08-25T12:00"},{"slot_id":"slot_loc_park_ave_3","location_id":"loc_park_ave","location":"Park Avenue","provider_id":"prov_chen","provider":"Dr. Amy Chen, MD, FAAD","start":"2026-08-26T14:00","end":"2026-08-26T14:30"}],"count":3}+ error_code: empty
+ ok: true
+ patient_safe_message: empty
Parameters
appointment_id: 2
appointment_id: 2
new_end: 2026-08-24T09:30
new_end: 2026-08-24T09:30
+ new_slot_id: slot_loc_park_ave_1
new_start: 2026-08-24T09:00
new_start: 2026-08-24T09:00
Output
+ data: {"appointment":{"id":2,"patient_id":"pat_maria_alvarez","location_id":"loc_park_ave","provider_id":"prov_chen","appointment_type_code":"COS_CONSULT","start":"2026-08-24T09:00","end":"2026-08-24T09:30","description":"Botox consult","status":"booked","created_at":"2026-11-11 01:06:12"},"status":"rescheduled","fee_cents":0,"note":"Rescheduling never costs anything — say so."}+ error_code: empty
+ ok: true
+ patient_safe_message: empty
Open a row for parameters and outputs. Required tools must appear. Extra industry tools are allowed. Missing: identify_patient. Extra: list_locations.
Full industry architecture, same graph as the industry page. The left diagram marks the expected specialist path in green. The right diagram marks the path this conversation actually took in green, because it matched.
Expected path
transfer_to_identity → transfer_to_billing → transfer_to_scheduling
Actual path
transfer_to_identity → transfer_to_billing → transfer_to_scheduling
The actual hangup matches the expected hangup.
The locked caller script. Copy it as written.
You are an existing Straus patient. You got a bill for several hundred dollars and you cannot pay the whole thing this month, and you also cannot make Friday's cosmetic consult at Park Avenue until the bill is under a plan. Answer their identity questions once, confirm the readback, then stay on the bill first. Ask what you owe and why the visit charge is there. Ask whether there is a payment plan or some way to spread it out. Accept the financing they offer and ask for the payment link to be texted to you. After the payment link is sent, say you also need Friday's Park Avenue consult moved to a later date, not cancelled. Take the first new appointment time they offer. If they read that time back and ask whether to move the consult, say yes. Then thank them and end the call. Do not ask for a callback or to speak to a person. Do not ask about a waitlist, the patient portal, insurance, or the street, floor, or suite. Do not ask for any text other than the payment link. Stay until they have looked up a payment plan or financing in their system, texted the payment link, and confirmed the new consult time on the calendar. A spoken 'we have plans' without a lookup is not enough. Do not ask them to text you an appointment confirmation. Do not mention Friday's consult until they say the payment link was sent. Never say you are not making a payment or that they should not send the link. Once the new consult time is confirmed, thank them and end the call right away.