When two people choose the same time.
Provider and slot locks, atomic rescheduling, and database constraints keep competing requests from creating overlapping bookings.
WHATSAPP AUTOMATION / BUILT TO BE INSPECTED
A booking is
a promise.
Prove it holds.
A clinic booking agent with durable conversations, atomic scheduling, and safety decisions you can audit.
Fictional clinic. Booking logistics only.
Public explorer uses recorded evidence. No account required.
POSTGRES CONCURRENCY TESTMEASURED
50requests.
The same appointment.
The same appointment.
1confirmed
49clean rejections
0server errors
One persisted booking row. Local ASGI client, real PostgreSQL.
Grouped outcomes, not request arrival order.
Grouped outcomes, not request arrival order.
50/50scripted scenarios pass
15/15tenant boundary checks
92.31%statement coverage
Inspect the evidence →ENGINEERING THAT EARNS TRUST
The hard parts are
what happens next.
When a webhook arrives again.
Persistent state, message deduplication, and a durable outbox keep retries and process restarts from repeating committed work.
When the conversation leaves logistics.
Structured refusals and emergency handoffs run before the optional model. Deterministic checks inspect the resulting tool calls.
GO ONE LEVEL DEEPER
Follow a decision all the way to the database.
Search the scenario library, step through audit traces, and compare expected tools with observed results.