Fig. 1 · One line on what the diagram shows, from the evidence kit.
The situation
A short paragraph of context: who uses this, what they were trying to do, and why the existing way fell short. Three or four sentences, specific enough that a reader outside the team can follow it without the jargon.
What made it hard
The constraint or failure that shaped the work. Name the real obstacle, with a number if the claims ledger has one, and say what a good outcome would have looked like.
What we built
How the system works and why it was built this way. Credit the team with "we", and use "I" only for the specific pieces that were mine. Three to five sentences, one idea each.