python and data engineering
turn APIs, files, tables, and schemas into datasets a model can actually use.
51 live chapters and 1491 runnable steps, from the core builder path through advanced AI/ML depth. Everything runs in the browser.
No signup, no card. About 75 minutes. You will leave with your first useful tool.
ai hands you code before you feel ready to read it. this lab covers the three reads that matter first: what the names hold, whether the function actually returns, and which branch of the if-chain really fires.
every api response, config file, and llm reply is lists and dicts nested in a tree. read the shape on sight, walk it with a loop, and catch the wrong-layer bug ai loves to ship.
when python crashes, it tells you exactly what happened and where. most non-engineers panic at the wall of text — and ai 'fixes' the crash by hiding it. learn to read the failure, then catch only what's worth catching.
when a list inside a function changes the list outside the function, that's mutation. ai does this constantly without flagging it, and it's the bug class that takes the longest to find.
every real script reads a file or calls an api — usually both. learn the with-block, the status-code families, and the retry rules: the seatbelts ai forgets to put on.
every ai feature you ship eventually calls a model api. learn the messages pattern, how to read the response, and the four lines ai writes every single time.
free-form text breaks every pipeline. learn the schema-first pattern ai uses to get reliable json back, validate it with pydantic, and catch the model's lies before they hit prod.
mcp is the new standard for plugging tools and data sources into ai agents. learn what an mcp server actually is, how claude code lists tools, and why this is replacing one-off integrations everywhere.
an agent isn't magic. it's a while loop. learn the actual cycle claude code, cursor, and every other agent uses: model returns tool_use, you run the tool, you send the result back, repeat until end_turn.
the difference between a one-shot ai session and a four-hour debugging spiral is almost always the first prompt. learn the structure that gets you usable code.
cursor and claude code commit on your behalf. reading those commits — and undoing the bad ones — is your job. learn the four-state model, the commands you'll run every day, and what `gh` does that `git` can't.
ai ships keys to github all the time. learn the .env pattern, why os.getenv is non-negotiable, what to do when a key leaks, and the gitignore lines you need on day one.
when an agent fails, the trace tells you exactly where. learn to read tool calls, tool results, and stop reasons — the json breadcrumbs every agent leaves behind.
if you can't test it, you can't ship it. learn the simple-but-strict eval patterns that separate ai features that work from ones that just feel like they do.
rag without the overengineering. chunking, embeddings, vector search, and the small set of patterns that make a model answer from your data instead of its training set.
the three numbers every shipped llm feature lives or dies by. token math, caching, streaming, batching, and the small set of decisions that move the product more than a model swap ever will.
when the model lies to your customer. the methodology for narrowing down what went wrong, the four most-common breakage classes, and the discipline that separates 'we shipped a fix' from 'we blamed the model and shrugged'.
wire it all together. the prompt, the call, the validation, the trace, the eval, the MCP tool. less a tutorial demo, more the smallest end-to-end llm feature you could ship to a real user. (retrieval and prompt-cache cost work live in chapters 22-23 — extend the capstone with them when you scale past the demo input set.)
claude code, cursor, aider, codex cli — they're all the same four layers wrapped around the same model api. learn what those layers are, what each adds, and what you'd build yourself if you had to.
every coding agent is a model plus a harness. the model is bought; the harness is engineered. learn the craft: how to ratchet rules from failures, fight context rot, design long-horizon loops, wire hooks as enforcement, and read the haas shift that's reshaping what you build vs buy.
you've never opened a terminal. by the end of this chapter you have, and you can move around your files, make folders, and read files without touching the mouse. it's a keyboard shortcut, not a cockpit. every tool in the rest of this course assumes you can do this, so we do it first.
you've used claude in a chat window. the claude cli is the same model with its hands on your actual files. this chapter installs it, signs you in, and runs your first real command. by the end you've watched an ai read, plan, and change things on your machine, and you know when to reach for the cli instead of the chat box.
you know the claude cli. the openai codex cli does the same job, an ai working in your terminal on your real files, with a different company behind it. this chapter installs it, signs you in, and runs your first command. most of what you already know carries straight over, so this chapter is mostly about what is different and when to reach for which.
a claude skill is a packaged set of instructions — your team's playbook — that claude loads when it's relevant, so nobody has to re-explain it. this chapter is for people who manage teams. it covers what a skill is, how a team shares and provisions skills, real examples for hr, legal, and ops work, when a skill beats a one-off prompt, and the governance you need before any skill touches real work.
the 2026 image model landscape, the prompts that work, and the pipeline that turns one good idea into a hundred ready-to-ship images. nano banana 2 for volume, nano banana pro for fidelity, flux, midjourney, ideogram, gpt-image-2. when each wins and what they cost.
video is the hardest content type to generate, the most expensive, and the most strategically interesting. learn the 2026 model lineup, the camera-control patterns that separate slop from craft, and the cost math that decides whether your idea is viable.
ai generates raw assets; code stitches them into something shippable. hyperframes, remotion, claude design — when each tool wins, how they combine, and the data-driven workflows that turn one template into a hundred videos.
tables are the working surface of applied ml. learn rows, columns, missing values, joins, aggregates, and the dataframe habits ai-generated notebooks assume.
most training data starts in a database. learn the select, join, filter, aggregate, and leakage traps that decide whether a model is learning signal or nonsense.
a dataset is a product surface. build ingestion, validation, partitions, manifests, and checkpoints so the next run is not a mystery.
vectors, probability, distributions, correlation, and uncertainty are not trivia. they are how you read model behavior without worshipping it.
labels, splits, baselines, training, prediction, and evaluation. the supervised workflow is the first complete model loop.
not every useful model has labels. cluster, compare, retrieve, and recommend by turning examples into useful neighborhoods.
accuracy is a blunt instrument. learn confusion matrices, precision, recall, thresholds, slices, and failure notes so model quality has evidence.
read tensor code without flinching. tensors, shapes, broadcasting, gradients, and autograd are the grammar of modern deep learning scripts.
the training loop is where models change. learn loss, gradients, optimizer steps, schedules, checkpoints, and the bugs ai ships there.
architecture literacy for builders: convolution, attention, tokens, decoding, kv cache, quantization, and what those choices do to cost and behavior.
features, runs, configs, artifacts, and registries are how ml work becomes repeatable instead of a lucky notebook.
serving a model means handling inputs, versions, routes, batch jobs, ci gates, rollback, and production failures deliberately.
the last mile: logs, drift, alerts, retraining decisions, cloud cost, gpu constraints, architecture docs, demos, and role stories.
how a working designer runs image models: prompts written like creative briefs, a brand bible that travels as structured data — with the design tokens that carry it onto screens — and the seeds, reference locks, and QA filters that make fifty generated assets look like one studio shipped them.
brief to voice-locked copy variants to batch plan to calendar to the numbers pass. the whole campaign as data your scripts can check — and an approval gate nothing skips. built for the person who owns the send button.
how a working support agent runs AI: a policy pack the drafter can't talk around, a banned-promises linter that holds every draft, golden eval sets that make each macro earn autonomy one intent at a time, and the escalation line where money, law, and anger stay human.
a client's voice measured from their own published copy, variant batches that pass the voice gate or die with a named reason, and a claim check that blocks the ship button while any fact is unsourced. corrections-log culture, as code.
how a working analyst runs AI: a cleaning log that accounts for every dropped row, sample-first checks that catch the plausible-but-wrong aggregation, a memo where every number carries the address of the cell that made it, SR 11-7-style challenge against the AI's recommendation, and the rerun test — same data, same code, same memo, or it isn't done.
how a working delivery lead runs AI builders: specs with acceptance checks written before the build, a review that runs the checks instead of admiring the demo, status roll-ups computed from acceptance records instead of standup vibes, and the not-ready call made on evidence you can read out loud to a steering committee.
how a working hr specialist runs AI: a data firewall that keeps employee records out of prompts by code instead of willpower, recruiting briefs where every claim cites a resume line, policy drafts that cannot publish without a named legal reviewer, and the adverse-action paper trail that survives a discrimination claim.
how a working ops lead gets the process out of one person's head and into automation that can be trusted: SOPs captured as versioned data with the invented steps hunted down, recurring checklists with an explicit auto-run vs named-approval line, exception queues instead of silent failures, and a receipt against the export for every number in the weekly report.
how a working lawyer runs AI: a citation-verification drill where every authority gets opened at the source (the fabricated ones always look right), clause extraction that's worthless without a pinpoint, privilege rules written as a routing table instead of remembered under deadline, and the review log you'd want in the record when opposing counsel moves for sanctions.
one sitting, one agent feature, end to end: a tool schema that makes the dangerous call a validation error, a loop that meters its own spend, golden cases wired before the router works, a trace you debug from instead of vibes, and the ratchet that turns tonight's incident into tomorrow's eval. practice at production tempo.
Chapters 35–47 go past the core builder path into applied ML work. They are live and optional — depth for when you want it, not the front door.
turn APIs, files, tables, and schemas into datasets a model can actually use.
learn the math, splits, baselines, and error habits behind useful models.
read PyTorch-shaped code, understand training loops, and know what architecture choices cost.
make features reproducible across training, batch jobs, and live inference.
compare runs with evidence, choose models deliberately, and keep a registry trail.
wrap models in APIs, handle bad inputs, and choose batch or realtime on purpose.
reuse the existing LLM spine for RAG, retrieval quality, structured output, and model-choice tradeoffs.
turn model checks into repeatable gates before changes reach users.
log predictions, spot data changes, and decide when retraining is worth it.
reason about GPUs, containers, queues, autoscaling, and cloud cost without treating them as magic.
package one system so another human can run it, inspect it, and trust the evidence.
translate the system into role stories for AI/ML engineer, MLOps, AI infra, and data science engineering interviews.