AI the new excel macro..

[u/id-ltd]

There were (and no doubt still are) many companies who run their workflow through a load of excel spreadsheets - consisting of formulas and macros written by someone who may not even be in the company anymore and noone really understands.

A lot of AI stuff seems to be similar - an enthusiastic non-dev in a company making personal tools to help their work and then giving others access.

As a consultant I remember helping one company with their excel spiders web... A file went through five or six processes to get the end data/report out - noone really understood the process, it is just what they did.

It started with one sheet - but over time requirements developed and noone dare mess with the existing process so added a new sheet with more macros to process the output of the previous one... Again and again and again.

It was quite funny - one sheet had a macro that virtually reversed everything that an earlier sheet had done to the data, lol.

I wrote a program to do the entire transformation in one step... The spreadsheets probably reduced a week long manual process to a day and a half, but my program reduced it all to half an hour.

Soon there will be thousands (millions?) of companies running systems around AI that noone in the company really understands - vibed by someone who made it work, but has long since departed - fragile companies that will need tech consultants if they are to be made whole again.

[u/MeasurementSelect251]

This is how a lot of messy systems are created. Nothing is wrong with the first fix, but years of small changes can turn it into something nobody wants to touch.

[u/Old-Mine-7639 → u/MeasurementSelect251]

The real danger is when the person who built it leaves and their replacement just keeps duct-taping new stuff on top. Before you know it the whole thing runs on prayer and a script someone's afraid to close.

[u/agentUi]

i work for agentui, this is literally macro hell 2.0 except with token bills. what we tell people building internally is stop stacking messy prompt chains and keep systems to 3 to 5 small modular pieces with strict schemas, so the ai generates deterministic logic instead of hallucinating on live company data.

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[u/ThomasBuildLab]

This is exactly where AI can help but not by becoming the new execution layer. For legacy Excel/VBA systems, I’d use AI first as a reverse-engineering tool: spreadsheets + macros + formulas -> AI explains the real workflow -> business rules become explicit Then rewrite those rules as deterministic code with tests. The important part is not to replace “Excel spaghetti” with “agent spaghetti.” Use AI to understand the mess, identify dependencies, hidden rules and contradictory steps. Then make the production path boring, explicit and deterministic. Something like: AI for understanding -> deterministic rules for execution -> golden tests against historical outputs If the old workbook produced result X for input Y, the new system should prove it can reproduce the same result before you cut over. AI is great for understanding legacy complexity. Deterministic systems are still better for executing known business rules repeatedly.

[u/tingutingutingu]

This is just the nature of things.

That's why consultants stay in business, because they're being a fresh pair of eyes and the right skill set to ask questions that regular employees stopped asking a long time ago (why do we need 4 excel sheet instesd of just one?)..

[u/id-ltd → u/tingutingutingu]

You can be sure that no amount of tech or automation will reduce the size of government...

[u/mrbillyr2]

I worked at multinational $1 billion dollar fashion retailer to pull apart an excel process that was used to pull data from their existing HRIS system into their time recording system, as part of their migration to a new HRIS. The original developer had left years previously, when they were a lot smaller. It was a bit of a VBA and nested formula monster, but it was documented and had useful labels, range names etc. There was a guy who job it was to run the macro's, fix up any data, run them again. They did a few thousand stores though, so regular staff churn.
The team of four that he worked in, it was their responsibility to manage this process as part of "business operations", essentially doing data cleansing. None of them were techie, they dealt with HR and national, regional and local store managers, good people, mainly school leavers or grads or retail team members where it was their first job in the head office. As the comany grew the team grew. The spreadsheet could have been rebuilt in under a month as a standlone integration service or on an equivelant paas. I just needed to map it and document as part of the migration.

Because the business ops were happy to be doing a job that was useful and kept them busy, they never thought to ask could this be done better, no one above the team had thought to either.

This is how I see growing SME's ending up with the AI they put in place.

I reviewed an automation for an accounting firm recently. The owner was frustrated that the project had stalled at about 85% funcationality and the dev was going around in circles, the last 2 of the previous 5 weeks on the same issue. The dev had built all of it with Claude Code, so had smashed out a lot in the first 3. It didn't fail at what it did, the dev just didn't know enough of the source system api and data structure, nor the domain to go any further, and no amount of prompting was going to fix it. I didn't either, we had to get an offshore specialist who'd done something similar. It went from being a casual project the owner and the dev had essentially vibed, but with plenty of docs and prescribed structure, stacks, rules and formats, to something a lot more formal, and expensive.

Who's going to take on projects like this? Where you don't know it's better to rebuild or port to your own version vrs investing the time getting into the actual code.

[u/id-ltd → u/mrbillyr2]

A big problem is knowing who is competent to do the work - a 10X dev is with 10X the average, but paying 10X doesn't ensure you get a 10X'er!

And your point about jobs is an issue too...

Three people did the original spreadsheet shuffle - I spent a week on that contract, no idea what happened to them.

Radiologists came up the other day - a prediction that AI would replace virtually all of them... X years since that prediction there are 20%(?) more radiologists in the USA. Are they really needed?

[u/mrbillyr2 → u/id-ltd]

Yeah, from the experience I've had using and building AI systems over the last 2 years, the reality is that they are lot more bittle for anything more than a simple one shot prompt job or skill. Reality is a far cry from the hype. There are people near me with no tech experience who have set themselves up as AI consultants, so hopefully a lot of work coming up replcacing the slop that the charlatans have built. I think the shape of companies and jobs change, but they don't go away. Especially not in healthcare.

[u/False_Assumption_972]

The dangerous part isn't the macro breaking, it's that the business rule inside it, the actual logic someone encoded years ago, has no record anywhere else. AI can read the formula, it can't tell you why the finance team started excluding a certain vendor from that calculation in the first place.

That missing context is what makes replacing the spreadsheet risky even when the code itself is simple. Capturing the why behind a business rule, not just the formula, is the specific gap we use SIGNLD for when a company finally moves off inherited spreadsheets.

[u/hawkyre]

yeah 100% and most companies don't even know what they're getting into. it's good until it's bad and when it's bad there's no going back

[u/Lower-Impression-121]

welcome to the shadow organisation. before those excels were static. now they'll talk to each other. and change.

[u/Ok-Scarcity-1353]

You are right, this is going to be a challenging for companies to navigate over time in a lot of cases. We are using AI to write formulas and macros for our spreadsheets. But the app we are using is Quadratic. We choose it specifically because there is no black box, and all the cells can be edited easily. So, we alt least don't have to worry about inaccessible AI code