Document Processing Agent
Invoices, contracts, receipts, and forms → structured data with confidence-tier human review
What a document processing agent actually does
You receive a stack of documents — invoices in your inbox, scanned receipts in a Drive folder, contracts uploaded to SharePoint. Someone reads each one and types data into your finance system, contract management system, or CRM. We replace that "reads and types" step.
Concretely, a document processing agent:
- Picks up the document from wherever it lands (email, SFTP, Drive, portal upload).
- Reads it with a vision-capable LLM — extracting structured data against a schema you define.
- Validates the extraction against business rules (PO matching, tax codes, vendor whitelist, duplicate detection).
- Routes by confidence: high → auto-post; medium → human review queue; low → reject with structured reason.
- Writes to your system of record with the original file attached and a full audit trail.
The reviewer interface — a single-page app showing the document beside the extracted fields — lets a human correct in 30 seconds what would take 5 minutes to key from scratch.
Anatomy of a working pipeline
[Email / SFTP / portal]
↓
[Ingestion queue (Firestore) with dedup hash]
↓
[Vision extraction (Claude vision / GPT-4o vision)]
↓ → typed payload validated against Zod schema
[Business rules (PO match, tax check, dup detect, vendor whitelist)]
↓
[Confidence routing]
├─ high: auto-post → ERP
├─ medium: review queue → human → ERP
└─ low: reject queue with structured reason
↓
[Audit log: extraction trace, decisions, reviewer actions, ERP refs]
Each box is observable. Each transition is logged. Each decision is reversible.
When this agent is the right call
You have a document processing agent's job when:
- Volume justifies the build. ~200+ documents per month at the bottom end. Below that, automation pays back too slowly.
- The cost per document of doing it manually is non-trivial. AP teams are typical. So are claim intake teams, KYC reviewers, and AR teams chasing remittances.
- You have a system of record to write to. Without a destination, structured data is just a CSV nobody reads.
- Errors are recoverable. A wrong line item is fixable. A wrong wire transfer is not. We always design review proportional to error cost.
It is not the right call when documents are highly varied free-form text with no schema, when volume is too low (a smart Power Automate flow may suffice), or when regulation requires a human signs off every record anyway.
Stack we tend to reach for
| Layer | Default |
|---|---|
| Vision extraction | Claude Sonnet 4.6 (best at structured output) or Gemini 2.0 Flash (cheaper for high volume) |
| Schema validation | Zod (TypeScript) end-to-end |
| Business rules engine | TypeScript on Cloud Functions |
| Storage | Firestore for metadata, Cloud Storage for originals |
| Reviewer UI | Next.js + shadcn/ui + Firebase Auth |
| ERP integration | Custom per ERP — we keep a library of patterns |
| Observability | Langfuse + Sentry + custom dashboard |
| Eval framework | Promptfoo + a manual sample set per document type |
Cost and timeline
| Scope | Typical investment |
|---|---|
| Discovery + schema spec (1 week) | €4,000–7,000 |
| Single doc-type pipeline (4–6 weeks) | €25,000–45,000 |
| Multi-doc pipeline (8–14 weeks) | €60,000–120,000 |
| Multi-ERP / multi-tenant (12–20 weeks) | €100,000–200,000 |
| Ongoing retainer (evals, new doc types) | from €2,000/month |
Pass-through LLM cost typically runs €0.01–€0.05 per document depending on length and number of pages.
Pitfalls we've watched clients fall into
- Believing the demo. Vendors will demo a perfect AP pipeline on their own clean sample invoices. Your invoices are not clean. Insist on shadow mode against your real documents before signing anything.
- Skipping the schema sprint. "Just extract everything" produces garbage. The schema sprint — sitting with your AP / ops team and defining what "structured invoice" means for your business — is the highest-leverage step in the whole build.
- No reviewer queue. Automation without human review is how clients end up with €50,000 of duplicate payments. Always build the queue, even if eventual auto-post rate is 95%+.
- No dashboard. If you can't see auto-post rate, error rate, and queue depth at a glance, the agent will quietly degrade.
Where it pairs
Document processing agents commonly chain into:
- Workflow orchestrators that take the extracted data and trigger downstream actions (approval workflow, payment, notification).
- Conversational agents that answer questions about the documents ("show me all unpaid invoices over €5,000 from Q1").
- Voice agents that confirm details with vendors when there's a mismatch.
See the Document Intake Agent case study for a full end-to-end build, or our How AI invoice processing works walkthrough for the technical deep dive.
If you have a document workflow you'd like an opinion on, drop us a note. One paragraph is enough.
Frequently asked questions
Related
AI Document Processing
Invoices, contracts, receipts, forms — extracted, validated, and pushed straight into your system of record.
Document Intake Agent
Supplier invoices end-to-end with an agentic pipeline
How AI invoice processing actually works (and where it breaks)
Modern AI invoice processing uses vision LLMs (Claude, GPT-4o, Gemini) to extract structured data from PDFs and images, then validates against business rules and routes by confidence — auto-post, review queue, or reject. The model is not the hard part; the schema, the reviewer UI, and the eval suite are.
AI agents for accounts payable: a deployment guide
AI agents in AP automate the high-volume, low-margin work of invoice keying and PO matching. Honest savings: €3-5 per invoice in loaded cost, 70-90% reduction in human handling time, payback typically 4-8 months on €25-50k builds. The agent isn't the hard part — the reviewer UI and the ERP integration are.
RAG done right: the patterns that survive production
Production RAG is engineering, not magic. The patterns that survive: hybrid retrieval (vector + BM25), rerank top-k with a cross-encoder, metadata filtering, source dating, citation rendering, sampled human review. Without these, your retrieval is good in the demo and broken in production.
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