Pestle · by Adaptive Systems
Pharmacy calls, answered. A person when it matters.
An AI voice agent answers the pharmacy's phone on Retell and Twilio: opening hours, services, prices, bookings and callbacks, from the pharmacy's own information. It says it is an AI, never gives clinical answers, and puts the caller through to staff the moment they ask. Every call lands in a staff app with the history, the follow-up and its cost.
A short browser call to a fictional pharmacy, a few a day. The staff app is password-protected.
Pestle's own site: the live numbers and an annotated real call- INPhone lineTwilio number · or a browser call
- 01VoiceRetell AI · speech to text · British voice
- 02AssistantClaude 5.5 Haiku · says it is an AI
- 03ToolsPestle API · signed · one pharmacy per key
- 04Identityname + date of birth · checked by code
- 05Hand overtransfer at once · or a callback, read back
- OUTStaff apptimeline · requests · audit · cost
- Demo scenarios
- 7 / 7
- the pharmacy's acceptance list, all built
- Seen on a real call
- 3
- enquiry, unanswered transfer, cost per call
- Automated tests
- 93
- signatures, isolation, verification, erasure
- Cost a minute
- $0.095
- first real call, Retell's own figure
As of 4 November 2026. Live numbers on Pestle's own page.
What a phone AI agent does
The routine calls, handled. The rest, handed over.
A pharmacy's phone rings with the same questions all day. The agent takes those, books what can be booked, and makes sure everything else reaches a person with the context.
Answers from approved information
Opening hours, closures, services, prices, collection and delivery, read from the pharmacy's own settings during the call. Nothing invented.
Books and cancels
Real free times, a booking with a spoken reference, cancellation on request. The database refuses double bookings.
Caller ID is a hint, never proof
A patient's history is read only after name and date of birth match, checked by code, with limits on failed attempts per call, number and patient.
A person, straight away
Asking for a person starts a warm transfer at once: no questions, no identity check first, a one-line briefing for whoever picks up.
Never stuck
Nobody answers: the assistant says so, offers a callback, reads the number back before saving it, and the request lands in the staff queue.
No clinical answers
No prescription status, stock or medical advice: there is no tool that could look them up, and Retell's guardrail on regulated advice is on.
How it works
The model talks. Code decides.
- 01
The call comes in
On the pharmacy's Twilio number, carried to Retell over an elastic SIP trunk (or a browser call). Retell handles speech, the British voice and interruptions.
- 02
The model talks
Claude 5.5 Haiku keeps the conversation short. It sees only what a tool returns: no database, no records.
- 03
Code decides
Every fact, free time, booking and identity check comes from Pestle's API: signed by Retell, scoped to one pharmacy by its own key and agent, enforced by PostgreSQL row-level security.
- 04
History after a check
Name and date of birth matched by code, then only what is relevant: open requests, bookings, earlier calls, each labelled patient said, verified or AI summary.
- 05
Hand over or call back
A warm transfer to the staff line; if nobody answers, a callback request with the number read back.
- 06
Staff close the loop
Calls with transcript, AI summary, outcome and cost (Retell + Twilio); requests to assign and resolve; patient timelines; reports; an audit log nobody can edit.
Patient data
Handled as health data, because it is.
UK GDPR and the Data Protection Act 2018, from the first line of code. The demonstration runs on fictional pharmacies and patients.
- Health data is special category data (UK GDPR Art. 9): the system is built for it, even with fictional data.
- Each pharmacy separated by the database (row-level security), tested so one pharmacy's key never reaches another's patients.
- Erasure of a patient, a call or a phone number, including Retell's copy through its API; an erased call stays erased.
- Retention per pharmacy applied daily; an append-only audit log; Retell's per-number caller memory off.
Built with
- Retell AI
- voice agent: speech, voice, turn-taking, transfer
- Twilio
- the number, elastic SIP trunk, price per call
- Claude 5.5 Haiku
- the conversation model, run by Retell
- FastAPI + PostgreSQL 16
- tools, webhooks, identity checks, row-level security
- Next.js 16
- the staff app and Pestle's own site
- ElevenLabs
- the same build on our Front Desk receptionist
Questions
Asked before every rollout.
What is Pestle?
Our AI phone assistant for pharmacies, built first as a working demonstration for a UK pharmacy group: an AI voice agent on Retell AI and Twilio, and a staff app that keeps every patient's communication history and the follow-up.
Can I talk to it?
Yes: the demo pharmacy takes a few short browser calls a day from its page, on your microphone. The staff app is password-protected; ask for a walkthrough.
Does it give medical advice?
No. It has no access to prescriptions, stock or records and no tool that could look them up; those questions go to the pharmacy team.
Can you build one for my business?
Yes: the same build works for clinics, dental practices, vets and any business that books by phone. The agent on Retell or ElevenLabs, your number on Twilio, your calendar and CRM.
See them run on real data.
The apps run real models on every click, so they sit behind a password. Ask for a login or a guided walkthrough: talk to our AI receptionist in Front Desk, drop invoices into Docket, or load forged applicants into Dossier. Or try them in public: score a lead, read your invoice, forge an applicant, or connect Docket and Dossier to Claude. Or hire us to build yours.