BUILDZN / WORK
Invoice to cash agent
Match synthetic invoices and bank lines, retain exceptions, and prepare reminders that require approval.
Synthetic data. This is a portfolio implementation with recorded command line runs. No customer data, paid model calls or hosting deployment were used.
Tests and demos use a deterministic mock provider. A Claude adapter sits behind the same interface; its live quality remains unmeasured.
Problem
Partial payments, duplicate bank lines and missing references make an invoice balance hard to trust. A reminder also needs to survive worker restarts without being delivered twice.
Architecture
1. Import and reconcile
PostgreSQL stores invoices, bank lines and allocations. Integer minor units preserve balances; ambiguous references go to review.
2. Persist the workflow
Day-14 reminder jobs and completed steps remain in the database. A polling worker resumes pending work after restart.
3. Prepare and review
A mock or Claude provider drafts text. Customer history adds an escalation record. A trusted operator approves the current balance and draft.
4. Dispatch atomically
A transactional demonstration mailbox shares its commit with the delivery checkpoint. Retries cannot create another mailbox entry.
Tradeoffs
- Reconciliation locks all invoices in a stable order. This is easy to inspect and test, but limits throughput.
- The transactional mailbox proves local delivery idempotency. A real email transport would need its own durable idempotency contract.
Test results
39 distinct test cases passed in at least one appropriate environment. Zero failures in the linked CI run.
| Environment | Passed | Skipped |
|---|---|---|
| Native PostgreSQL | 38 | 1 |
| Embedded PostgreSQL | 37 | 2 |
The embedded disk-reopen test runs only on the embedded engine. The two process-kill tests run only on native PostgreSQL. Both native process-kill tests passed.
Both native process-kill tests passed: reconciliation and reminder delivery rolled back and resumed without duplicate delivery.
Docker Compose built and ran the seeded demo from a fresh Actions checkout. These fixture measurements do not establish production accuracy, security certification or business outcomes.
Verified code: d3e973044a42f6f374a0f7a7882b49a0b5b1f09b
Recorded demo output
Real stdout from the Docker demo in the linked CI run. All records, identities and messages are synthetic.
All data synthetic. Transport: transactional demo mailbox.
Invoice 10000 USD minor units. Partial payment 4000. Remaining: 6000
Dry run: dry-run
Approved delivery: delivered
Retry: delivered
Mailbox records: 1
Persisted steps: [
{ job: 'reminder:demo-invoice', name: 'delivered' },
{ job: 'reminder:demo-invoice', name: 'drafted' },
{ job: 'reminder:demo-invoice', name: 'escalated' }
]Known limits
- No bank integration, currency conversion, public authentication or real email delivery.
- The Claude adapter is implemented but live model quality was not measured.
- Approval uses a trusted local operator identity. This is a CLI showcase.