Note 01 · Context Engineering

The Context Layer

Every company I've watched adopt AI hits the same wall: the answers are fluent, confident, and useless. The instinct is to feed it more data. That instinct is what keeps it broken.

Published 2026-08-01 ~9 min read Interactive ×2

You connect an assistant to your business. You ask it something an experienced employee could answer in four seconds — "can we rush this customer's order?" — and you get back a paragraph that would apply equally well to a bakery, a machine shop, or a law firm.

So you give it more. You point it at the shared drive. You export three years of Slack. You dump every PDF anyone has ever written. And the answers get worse — not vaguer now, but confidently wrong in ways that are much harder to catch.

The problem was never how much the model could see. It was that nobody had ever written down how the business actually works in a form anything could use. That written-down thing is what I call the context layer, and building one is mostly an editing job, not an engineering job.

More data is not more context

This is the part that takes people a while, so it's worth being blunt about it: an unfiltered dump of your company's files is worse than nothing. Not slower. Not noisier. Actively worse, because it converts a model that would have said something obviously generic into one that says something specific and wrong.

The mechanism is simple. Your shared drive contains the current rush-order policy and also the one from 2019 that nobody deleted. It contains the real price list and four stale quotes. Nothing in the folder structure says which is true. A human knows to ignore the old one because they remember it being replaced. The model has no such memory — it just finds a confident, well-formatted, authoritative-sounding document and uses it.

Play with it. Toggle sources on and off and watch what happens to the same question.

The Context Mixer Interactive
The question, unchanged every time
"A customer emailed asking if we can rush their order to arrive by Friday. What do we tell them?"
Specificity 0
Accuracy 0
Trustable 0
Note the shape of it: three curated sources beat six sources every time, and the single retired policy document does more damage than all the raw volume combined. "Trustable" is the only meter that matters — it's whether a person can act on the answer without checking it first, which is the entire point.

What actually belongs in it

A context layer is not a document repository. It's a written account of how the business operates, maintained deliberately, small enough that a person could read the whole thing in an afternoon.

Belongs

  • How the work actually flows — quoting, intake, fulfillment, escalation
  • Decision rules with their thresholds ("rush fee applies under 5 business days")
  • Who owns what, and who to route to
  • Vocabulary — what your team means by words outsiders would read differently
  • The exceptions people carry in their heads
  • Live connections to systems of record, for anything that changes daily

Doesn't

  • Anything superseded but not deleted
  • Raw chat exports — enormous volume, almost no durable truth
  • Data that changes daily, frozen as text (connect it instead)
  • Documents nobody can vouch for
  • Four versions of the same policy
  • Anything you included because deleting it felt wasteful
The test I use

For any candidate document: can someone on the team confirm this is currently true? If no one can, it doesn't go in — regardless of how much work went into writing it. Unattributable content is the raw material of confident wrong answers.

Never add anything without stating why

This is the single practice that changed my results the most, and it sounds almost too simple to matter.

I don't drop material into a knowledge base. I talk through it first — what this document is, why it's going in, what questions it's supposed to make answerable, and what it should not be used for. Then it gets written in, in a structured form, rather than pasted in raw.

Bad:   [pastes 40-page operations manual]

Good:  This is our operations manual, current as of March.
       I want it in so the assistant can answer questions about
       escalation paths and turnaround commitments.
       Sections 1-3 are org history — skip them.
       Section 7 pricing is stale; we handle pricing live from
       the CRM, so leave it out entirely.

Two things happen. The obvious one: the stale pricing never enters the system, so it can never be retrieved and repeated back to a customer. The subtle one: stating the purpose out loud forces me to notice when I don't actually have one — and about a third of the time, that's the moment I realize the document doesn't need to go in at all.

Every piece of context should be traceable to a question someone actually asks. If you can't name the question, you're archiving, not building context.

Prune as aggressively as you add

The half of this nobody does. A context layer gets better through subtraction at least as often as addition, and the review pass is not optional maintenance — it's the work.

When I review a page I'm asking two questions: where is this thin, and where is it distracting. Thin means a question I'd expect it to answer, that it can't — that gets expanded. Distracting means content that competes with the thing that actually matters, pulling attention toward a plausible but wrong answer — that gets cut, even if it's accurate.

That second category is counterintuitive and it's where most of the gains are. True but irrelevant content is not harmless. It's a distractor, and the more authoritative it looks, the more damage it does.

Failure mode I walked into

My first version of this was a firehose. I added everything I could find, felt productive, and got answers that were more confident and less correct than before. It took me an embarrassingly long time to try deleting things — and the accuracy jump from cutting was bigger than anything I'd gotten from adding.

It decays, and that's the actual business

A context layer is not a deliverable. It's a living thing with a half-life. The business changes, the document doesn't, and the gap between them is invisible until someone acts on a wrong answer.

Here's what that looks like over eighteen months, with and without a monthly review pass.

Context Decay Drag the timeline
Day one Month 0 18 months
Unmaintained 96
Reviewed monthly 96
What drifted
Nothing dramatic happens. A price changes, someone leaves, a product ships. Each one is small, none of them announce themselves, and the assistant keeps answering with total confidence the whole way down.

This is why I think of the context layer as an operating responsibility rather than a project. Somebody has to own it, and the ownership is monthly and forever. That's not a flaw in the model — it's the same reason your CRM rots if nobody tends it.

The loop

Start from real questions

Collect the questions people actually ask each other — in chat, in meetings, over someone's shoulder. That list is your specification. Build to answer those, not to be comprehensive.

Add deliberately, with stated purpose

Nothing enters raw. Every addition comes with what it's for and what it shouldn't be used for. If you can't name the question it answers, it doesn't go in.

Connect what moves

Anything that changes faster than you'll update it should be a live connection to the system of record, not frozen text. Text is for stable things: rules, processes, definitions.

Test against known answers

Ask questions where you already know the correct answer. Wrong answers usually point at a specific distractor you can delete — the fix is almost always removal, not addition.

Review monthly — expand thin, cut distracting

Two passes. Where did it fail to answer something it should have? Expand. What's competing for attention with the thing that matters? Cut, even if it's true.

If you're starting this week

Don't begin with the shared drive. Begin with one workflow — the one where somebody gets interrupted most often — and write down how it actually works, including the exceptions that live in one person's head. That'll be two or three pages. It will outperform an entire indexed file server, and you'll have it by Friday.

Then resist the urge to scale it before it's correct. A small context layer that's true beats a large one that's mostly true, because "mostly true" is indistinguishable from "true" at the moment someone reads the answer.


Neal Meinke

I build AI systems inside businesses — context layers, system integrations, and internal tools that replace manual work. These notes are things I've learned doing it, published as I go.

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