Automations · Issue 01 · Kindling
From inbox to ledger: uploading invoices into your accounting system
A small team of agents that watch your supplier inbox, read every PDF, code it, ask a human only when it matters, and post the draft bill to your accounting system — built in Kindling in an afternoon.
The problem
Supplier invoices are a tax on growth
Accounts payable opens each file, eyeballs supplier and VAT, hunts for a PO, and keys lines into Xero or FreeAgent by hand. The cost isn't the typing — it's the delay, the rework when a line is coded wrong, and the lack of visibility into what's still sitting in the inbox.
Messy inputs
PDFs, scans, phone photos, credit notes forwarded into the same thread.
Brittle middle
Manual matching to suppliers and nominal codes; duplicates slip through.
No visibility
No one knows what's been done, what's pending, or where a bill got stuck.
The thinking
A small team of agents, not one big prompt
A single LLM call can't be trusted to both read an invoice and post it. We split the work across four cooperating agents — each with a narrow job, the right tools, and a single point where a human can step in if confidence drops.
Narrow agents with the right tools beat one giant prompt that tries to do everything at once.
Agent 1
Invoice Parser
Reads the email + PDF text, extracts supplier, dates, line items, VAT, total.
No tools
→Agent 2
Supplier & Coder
Looks up the supplier in FreeAgent, picks a nominal code, flags duplicates.
freeagent_search_contacts
→Agent 3 · HITL
Exception Reviewer
Pauses for a human only when something is off — new supplier, VAT mismatch, low confidence.
Human in the loop
→Agent 4
FreeAgent Poster
Creates the draft bill, attaches the PDF, moves the email to "Processed".
freeagent_create_bill · freeagent_attach_file · email_move
The build
Building it in Kindling
Kindling gives us the four building blocks we need: connected integrations (Gmail + FreeAgent), agents with tools, a workflow that chains them, and a trigger that watches the inbox. Here's how it comes together. Screenshots on this page are a bit narrower on large screens; tap or click any of them to open at full resolution.
Connect Gmail and FreeAgent
One-click OAuth from Project Settings → Integrations. This is what unlocks every tool the agents will use downstream.
Build the four agents
Each agent gets a tight system prompt and only the tools it needs. The Exception Reviewer has "Requires human input" toggled on.
Anatomy of an agent
The Supplier & Coder is the most interesting one — it reads the parsed invoice, calls freeagent_search_contacts to confirm the supplier exists, then proposes a nominal code based on the line items.
Chain them into a workflow
A workflow is just an ordered list of agents. Output of each step becomes the input of the next. We call this one "Invoice → FreeAgent".
Watch the inbox with a Gmail trigger
An "App" wraps the workflow with a webhook and a Gmail trigger. We use label-as-queue mode: anything that lands in the to-process-invoices label gets a workflow run; the Poster agent removes the label at the end. One run per email, PDF attachments saved to disk automatically.
The refinement
Refining it in practice
The first run was 80% right. The next ten runs got us to 99% — and we did it without redeploying anything. Every disagreement between the agents and the human reviewer became a few-shot example pasted into a system prompt, or a tighter rule about when to pause. The HITL refinement chat is where most of that learning happens.
In the room where it improves
HITL is not a failure mode — it is where the workflow learns your finance team's judgement.
The result
What "live" looks like
A supplier emails an invoice. Within five minutes a draft bill is sitting in FreeAgent with the PDF attached, coded to the right nominal, and the email is moved to "Processed". The team only sees the ones that genuinely need them.
4
Agents in the chain
<5 min
Email to draft bill
1
Human checkpoint
100%
Auditable steps