I Have a TBI, So I Built an External Brain
The bill had two reminders on it. One in my phone, one on a sticky note on the monitor. I wrote both myself, which means at some point I stood in front of that monitor, fully informed, pen in hand, doing everything a responsible adult is supposed to do.
It auto-pulled anyway, three days late, with a fee attached — because a reminder is not a memory. A reminder is a bet that future-you will be the kind of person who sees a sticky note and acts on it at the exact moment it matters. I lose that bet a lot. The note was still there when the fee posted. I’d looked at it so many times it had become furniture.
This isn’t a story about being bad with money. The money part was fine — the money part was planned. It’s a story about the machinery that’s supposed to carry a plan from “decided” to “done,” and what you do when that machinery is broken.
Mine broke in 2011.
What actually breaks
I was active-duty US Army. I’ll skip the memoir; the relevant part is that I came home with a traumatic brain injury, and a TBI is not one injury. It’s a demolition of specific subsystems while the rest of the building stays standing.
For me, the damage landed on three things. Working memory — the mental desk where you hold a phone number while you dial it, or the first half of a sentence while you say the second half. Mine is a desk the size of a coaster. Initiation — the ignition system between deciding to do a thing and physically starting it. Mine misfires, and no, it doesn’t respond to “just start.” Retrieval under load — words, names, the thing I walked into this room for. On a calm day I can feel the word sitting there, shaped and ready, behind a door that won’t open. On a stressed day there’s no door.
Here’s the sentence I want you to underline, because nobody said it to me for years: this is hardware, not character. If you’ve spent a decade being told — or telling yourself — that you’re lazy, scattered, flaky, or not trying hard enough, and meanwhile you’re white-knuckling systems of sticky notes and alarms and shame: the problem may not be your effort. It may be that effort is the wrong tool, the way pushing harder on the gas is the wrong tool for a dead battery.
The rest of my file is heavier than one acronym, and I’m not going to unpack it here. The TBI is enough to make the point.
The turn
We have a word for technology that replaces a broken biological function: a prosthetic.
Glasses are a prosthetic for focal length. Hearing aids for hair cells. An insulin pump replaces a feedback loop your pancreas was supposed to run. Nobody looks at a knee brace and says “real hikers strengthen their ligaments through discipline.” We moralize exactly one organ. If your memory is damaged, the culture hands you a planner and a pep talk and calls it a day.
So here’s the thesis, and it’s the whole essay: executive function can be external. Memory, initiation, continuity — the three things my injury broke — can run on hardware outside my skull. Not as a metaphor. As an actual system, running right now, on a small computer in my house.
This is not a productivity essay. I don’t care about your inbox. This is a prosthetics essay.
The build
I’m a security engineer by trade, so my version is more elaborate than yours needs to be. But the architecture is three pieces, and each one maps to a broken subsystem.
The wiki — external memory. One folder of plain text files. Every appointment, every decision, every open question, every “wait, didn’t the doctor say the opposite last time?” has a page and an address. The part that makes it different from every journal you’ve abandoned: an AI agent maintains it, and I curate it. I hand it raw material — a visit summary, a screenshot, a rambling voice note — and it files the facts, links them to what’s already there, and flags what contradicts what. Mine is a few hundred pages deep now. When I need to know something, I don’t strain at the door that won’t open. I ask, and the system answers with a citation to the page where past-me left the receipt.
The design principle: I don’t remember; I query. Saying that out loud felt like defeat for about a week. Then it felt like taking off a backpack I’d been wearing so long I’d stopped counting it as weight.
The daemon — external initiation. A “daemon,” in computing, is a program that runs quietly in the background without being asked. Mine lives on a mini-PC about the size of a hardcover book and runs the loops I can’t sustain, on a schedule that never has a bad day. Every morning it messages me:
Morning report — Tuesday
• Refill window opens today; pharmacy closes at 6.
• Two auto-pulls hit Thursday. Safe-to-spend is updated.
• One reply owed from yesterday (flagged, drafted).
• You logged a decision Sunday and never closed it. Link below.
Notice what that is. It isn’t a to-do list I wrote — writing the list was never the broken part. It’s the system acting first: checking the pharmacy calendar, the bank, the open loops, and putting the result in front of me at the moment of action. Cron — the humble scheduler that’s been in every Unix machine since the seventies — is my basal ganglia now. The ignition that misfires in my head fires on schedule in the box.
The log — external continuity. Every change to the system gets an append-only entry: what happened, when, and — this is the part that changed my life more than I expected — why. Decisions are recorded with the reasoning attached, alternatives considered, and the condition under which I’d revisit them. Contradictions between old and new information get flagged instead of silently papered over. Open questions are marked as open instead of forgotten.
Why that matters: when your working memory is damaged, you re-litigate. You make a sound decision in March and by May you can’t remember making it, let alone why, so you make it again — sometimes differently, always expensively. The log makes past-me a reliable witness. I can disagree with him, but I can’t lose him.
The rule that holds it together: the human curates, the agent maintains. The machine never decides what matters — I do that, on my good hours, when judgment is available. The machine does the remembering, the nudging, the filing, the re-checking: the parts that require reliability, which is precisely what I don’t have. This is not automation replacing judgment. It’s scaffolding under judgment. Get that backwards and you’ve built a robot boss; get it right and you’ve built a brace.
What it doesn’t fix
I owe you the limits section, because the internet is currently drowning in people who want to sell you AI as a personality transplant.
It doesn’t fix grief. It doesn’t fix the anniversaries. It doesn’t fix the day when the injury plus everything underneath it decides you’re not getting up at full strength — the daemon sends the morning report into the void on those days, and the void does not check its messages. What it does is make those days cheaper: the system holds the world steady, nothing catches fire while I’m down, and re-entry costs hours instead of weeks. That’s not a small thing. It’s also not a cure, and I won’t call it one.
It requires maintenance. The wiki decays without a weekly curation pass — mine gets a lint, like code, and when I skip two weeks I can feel the trust in the system drop, which is deadly, because a memory prosthetic you don’t trust is worse than none. Budget the maintenance like physical therapy: boring, non-optional, the price of the function.
It costs real money. Not “startup” money — think a used-mini-PC-once plus a monthly AI bill in streaming-subscription territory. But not free, and I’d rather tell you that here than let you discover it in month two.
And it took me — a person who does this professionally — months of evenings to build. That part is getting easier fast, and the patterns are all writable-down, which is why I’m writing them down. But I won’t pretend I whistled it up in a weekend.
Who this is for
Maybe you have a TBI. Maybe it’s ADHD, and the executive-function failures are congenital instead of concussive — the scaffolding doesn’t care about etiology. Maybe it’s long COVID and the brain fog that nobody can see and everybody doubts. Maybe you’re a caregiver running two people’s executive function on one person’s hardware, or you’re deep in burnout, or you’re a veteran like me whose file has more acronyms in it than a defense contract.
The common thread isn’t a diagnosis. It’s this: your working memory can no longer be trusted with your life admin, and every system you’ve tried assumed it could. Planners assume you’ll open the planner. Reminder apps assume the reminder will find you actionable. All of it assumes intact initiation — the exact thing that’s broken.
You do not need to be technical to want the alternative, and the alternative is one sentence long: one system that remembers, one that nudges, one that logs. A memory, an ignition, a witness. Everything I run is an elaboration of those three, and the simplest version of each is genuinely small.
The same bill, one year later
The auto-pull still exists. Same biller, same date, same me — same coaster-sized desk, same door that sticks, same ignition that misfires. Nothing about my brain healed in that year. That’s what “prosthetic” means: the leg doesn’t grow back; you walk anyway.
But this year, three days before the pull, a message arrived at 7 a.m. between the weather and the pharmacy note: the amount, the date, the account it draws from, and a one-line confirmation that the money was already positioned — because a quiet process checked, the way it checks every morning, whether I’m brilliant that day or barely vertical.
I read it over coffee, thought handled, and got on with my life.
That’s the whole pitch. Not superintelligence. Not the future of work. A daemon that quietly runs the parts of your life your injury dropped — built once, maintained weekly, trusted daily.
I’m writing up the build, one piece a month, right here. If you want the full blueprint now instead of serialized, the guide is on the products page. Start with the morning report. It’s the smallest piece, and it’s the one that makes you believe the rest.
Kyle is a US Army veteran and healthcare security engineer. He has a TBI, a wiki that remembers for him, and a daemon that runs the rest.
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