CareFlow Build Journal · Entries 001–020

The journey behind the product.

A public engineering journal about building CareFlow: the architectural decisions, failed assumptions, security boundaries, clinical context, and evidence that shaped the system.

Built in sequence.
Explained in public.

Each entry captures one decision in chronological order. Together they show how a healthcare SaaS moves from infrastructure and contracts to identity, isolation, evidence, clinical rules, and deployment—without pretending that a design choice alone creates compliance or clinical certainty.

001

Before the First Feature

Why the AWS account structure and evidence boundary came before application code.

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002

The Deliberate Detour

Why CareFlow begins with controlled flat files before attempting EMR integration.

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003

The Meeting Is Short. The Preparation Is Not.

The clinical work and information flow behind a hospice IDG meeting.

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004

The Contract Came Before the Data

Mapping agreements, eligible services, and configuration to every potential PHI route.

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005

The Infrastructure Before the Infrastructure

Bootstrapping Terraform state without losing the security boundary along the way.

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006

The Deployment Credential We Never Stored

Using GitHub OIDC to exchange identity for short-lived AWS access.

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007

Isolation You Can Prove

Layering PostgreSQL roles and row security for testable tenant isolation.

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008

The Backup That Failed Quietly

What a macOS automation failure taught us about observable, recoverable backups.

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009

The Word We Removed

Why CareFlow leads with the clinical workflow instead of the AI implementation.

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010

The Invitation Cognito Could Not Send

Where a managed invitation flow stopped fitting CareFlow’s threat model.

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011

The Runbook That Rejected the Schema

How two reasonable documentation requirements exposed an impossible database rule.

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012

The Picture That Found the Gaps

Turning architecture into a review surface instead of a decorative diagram.

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013

Price the Switch Before Turning It On

Making cost impact part of the engineering contract for every AWS change.

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014

Nine Days, Measured in Evidence

What “first sign-in” meant when the milestone included its security foundation.

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015

Refusing to Guess

Why deterministic, explainable rules precede any future clinical classifier.

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016

Put the Limit in the Signed Contract

Choosing an upload mechanism that carries enforceable size constraints.

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017

The Quiet Copy

Treating audit evidence as governed data rather than harmless metadata.

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018

The Runner Inside the Boundary

Running database migrations without creating a permanent administrative doorway.

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019

Earn the Always-On API

Choosing compute from measured workload needs rather than architectural aspiration.

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020

A Blank Field Is Not a No

Separating absent documentation from negative clinical evidence.

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