How Deep Is Too Deep?¶

When "Master ML" Is the Wrong Next Step¶
Jose Alekhinne / 2026-02-12
Have you ever felt like you should understand more of the stack beneath you?
You can talk about transformers at a whiteboard.
You can explain attention to a colleague.
You can use agentic AI to ship real software.
But somewhere in the back of your mind, there is a voice: "Maybe I should go deeper. Maybe I need to master machine learning."
I had that voice for months. Then I spent a week debugging an agent failure that had nothing to do with ML theory and everything to do with knowing which abstraction was leaking.
This post is about when depth compounds and when it does not.
The Hierarchy Nobody Questions¶
There is an implicit stack most people carry around when thinking about AI:
| Layer | What Lives Here |
|---|---|
| Agentic AI | Autonomous loops, tool use, multi-step reasoning |
| Generative AI | Text, image, code generation |
| Deep Learning | Transformer architectures, training at scale |
| Neural Networks | Backpropagation, gradient descent |
| Machine Learning | Statistical learning, optimization |
| Classical AI | Search, planning, symbolic reasoning |
At some point down that stack, you hit a comfortable plateau: the layer where you can hold a conversation but not debug a failure.
The instinctive response is to go deeper.
But that instinct hides a more important question.
Does depth still compound when the abstractions above you are moving hyper-exponentially?
The Uncomfortable Observation¶
If you squint hard enough, a large chunk of modern ML intuition collapses into older fields:
| ML Concept | Older Field |
|---|---|
| Gradient descent | Numerical optimization |
| Backpropagation | Reverse-mode autodiff |
| Loss landscapes | Non-convex optimization |
| Generalization | Statistics |
| Scaling laws | Asymptotics and information theory |
Nothing here is uniquely "AI".
Most of this math predates the term deep learning.
In some cases, by decades.
So what changed?
Same Tools, Different Regime¶
The mistake is assuming this is a new theory problem.
It is not.
It is a new operating regime.
Classical numerical methods were developed under assumptions like:
- Manageable dimensionality
- Reasonably well-conditioned objectives
- Losses that actually represent the goal
Modern ML violates all three: On purpose.
Today's models operate with millions to trillions of parameters, wildly underdetermined systems, and objective functions we know are wrong but optimize anyway.
At this scale, familiar concepts warp:
- What we call "local minima" are overwhelmingly saddle points in high-dimensional spaces
- Noise stops being noise and starts becoming structure
- Overfitting can coexist with generalization
- Bigger models outperform "better" ones
The math did not change.
The phase did.
This is less numerical analysis and more *statistical physics: Same equations, but behavior dominated by phase transitions and emergent structure.
Why Scaling Laws Feel Alien¶
In classical statistics, asymptotics describe what happens eventually.
In modern ML, scaling laws describe where you can operate today.
They do not say "given enough time, things converge".
They say "cross this threshold and behavior qualitatively changes".
This is why dumb architectures plus scale beat clever ones.
Why small theoretical gains disappear under data.
Why "just make it bigger", ironically, keeps working longer than it should.
That is not a triumph of ML theory.
It is a property of high-dimensional systems under loose objectives.
Where Depth Actually Pays Off¶
This reframes the original question.
You do not need depth because this is "AI".
You need depth where failure modes propagate upward.
I learned this building ctx. The agent failures I have spent the most
time debugging were never about the model's architecture.
They were about:
-
Misplaced trust: The model was confident. The output was wrong. Knowing when confidence and correctness diverge is not something you learn from a textbook. You learn it from watching patterns across hundreds of sessions.
-
Distribution shift: The model performed well on common patterns and fell apart on edge cases specific to this project. Recognizing that shift before it compounds requires understanding why generalization has limits, not just that it does.
-
Error accumulation: In a single prompt, model quirks are tolerable. In autonomous loops running overnight, they compound. A small bias in how the model interprets instructions becomes a large drift by iteration 20.
-
Scale hiding errors: The model's raw capability masked problems that only surfaced under specific conditions. More parameters did not fix the issue. They just made the failure mode rarer and harder to reproduce.
This is the kind of depth that compounds.
Not deriving backprop.
Understanding when correct math produces misleading intuition.
The Connection to Context Engineering¶
This is the same pattern I keep finding at different altitudes.
In "The Attention Budget", I wrote about how dumping everything into the context window degrades the model's focus. The fix was not a better model. It was better curation: load less, load the right things, preserve signal per token.
In "Skills That Fight the Platform", I wrote about how custom instructions can conflict with the model's built-in behavior. The fix was not deeper ML knowledge. It was an understanding that the model already has judgment and that you should extend it, not override it.
In "You Can't Import Expertise", I wrote about how generic templates fail because they do not encode project-specific knowledge. A consolidation skill with eight Rust-based analysis dimensions was mostly noise for a Go project. The fix was not a better template. It was growing expertise from this project's own history.
In every case, the answer was not "go deeper into ML".
The answer was knowing which abstraction was leaking and fixing it at the right layer.
Agentic Systems Are Not an ML Problem¶
The mistake is assuming agent failures originate where the model was trained, rather than where it is deployed.
Agentic AI is a systems problem under chaotic uncertainty:
- Feedback loops between the agent and its environment
- Error accumulation across iterations
- Brittle representations that break outside training distribution
- Misplaced trust in outputs that look correct
In short-lived interactions, model quirks are tolerable. In long-running autonomous loops, they compound.
That is where shallow understanding becomes expensive.
But the understanding you need is not about optimizer internals.
It is about:
| What Matters | What Does Not (for Most Practitioners) |
|---|---|
| Why gradient descent fails in specific regimes | How to derive it from scratch |
| When memorization masquerades as reasoning | The formal definition of VC dimension |
| Recognizing distribution shift before it compounds | Hand-tuning learning rate schedules |
| Predicting when scale hides errors instead of fixing them | Chasing theoretical purity divorced from practice |
The depth that matters is diagnostic, not theoretical.
The Real Answer¶
Not turtles all the way down.
Go deep enough to:
- Diagnose failures instead of cargo-culting fixes
- Reason about uncertainty instead of trusting confidence
- Design guardrails that align with model behavior, not hope
Stop before:
- Hand-deriving gradients for the sake of it
- Obsessing over optimizer internals you will never touch
- Chasing theoretical purity divorced from the scale you actually operate at
This is not about mastering ML.
It is about knowing which abstractions you can safely trust and which ones leak.
A Practical Litmus Test¶
If a failure occurs and your instinct is to:
- Add more prompt text: abstraction leak above
- Add retries or heuristics: error accumulation
- Change the model: scale masking
- Reach for ML theory: you are probably (but not always) going too deep
The right depth is the shallowest layer where the failure becomes predictable.
The ctx Lesson¶
Every design decision in ctx is downstream of this principle.
The attention budget exists because the model's internal attention mechanism has real limits: You do not need to understand the math of softmax to build around it. But you do need to understand that more context is not always better and that attention density degrades with scale.
The skill system exists because the model's built-in behavior is already good: You do not need to understand RLHF to build effective skills. But you do need to understand that the model already has judgment and your skills should teach it things it does not know, not override how it thinks.
Defense in depth exists because soft instructions are probabilistic: You do not need to understand the transformer architecture to know that a Markdown file is not a security boundary. But you do need to understand that the model follows instructions from context, and context can be poisoned.
In each case, the useful depth was one or two layers below the abstraction I was working at.
Not at the bottom of the stack.
The boundary between useful understanding and academic exercise is where your failure modes live.
Closing Thought¶
Most modern AI systems do not fail because the math is wrong.
They fail because we apply correct math in the wrong regime, then build autonomous systems on top of it.
Understanding that boundary, not crossing it blindly, is where depth still compounds.
And that is a far more useful form of expertise than memorizing another loss function.
If you remember one thing from this post...
Go deep enough to diagnose your failures. Stop before you are solving problems that do not propagate to your layer.
The abstractions below you are not sacred. But neither are they irrelevant.
The useful depth is wherever your failure modes live. Usually one or two layers down, not at the bottom.
This post started as a note about whether I should take an ML course. The answer turned out to be "no, but understand why not". The meta continues.