⭐ Recommended 🔥 Trending Spec-Driven Development Foundations: From Philosophy to Operating Model
Learn to write specs that agents actually obey, ship code as a cache of a durable spec, and operate the spec→context→evals trinity on real codebases. Vendor-agnostic, tool-agnostic, brownfield-ready — the methodology course that pairs with any agentic stack.
Oleksii Anzhiiak
Software Architect, Senior .NET Engineer & Co-Founder
By the end you'll be able to
- Treat specs as the durable artifact and code as its cache
- Operate the spec→context→evals trinity on real, brownfield codebases
- Write specs that agents actually obey — executable, named, negated where it matters
- Shift PR review from 600-line code diffs to 60-line spec deltas
- Recognise where spec-first is the wrong call — and know what to do instead
Is this course for you?
This is right for you if you…
- You finished #21 (Prompt Engineering) or #25 (Claude API) and your team is shipping AI features that quietly drift
- You're a Senior+ engineer asked to define how your team uses AI day-to-day — and want a methodology, not a hot take
- You've read the brand's spec-driven, context, and evals posts and want the structured deep-dive
Don't take this course if you…
- You haven't shipped production code with an AI tool yet — spec-driven only makes sense after you've felt the failure mode firsthand
- You're looking for a CLI walkthrough — this is methodology; OpenSpec Mastery (#29) is the applied tool course
- Your team isn't using AI tools at all yet — start with #21 and #26 first, then come back
Who teaches this
Oleksii Anzhiiak
Software Architect, Senior .NET Engineer & Co-Founder
Oleksii Anzhiiak is a Software Architect, Senior .NET Engineer, and Co-Founder of ToyCRM.com and ProfectusLab. With over 15 years of experience, he specializes in distributed systems, cloud infrastructure, high-load backend development, and identity platforms. Oleksii designs complex architectures, builds secure authentication systems, and develops modern engineering education programs that help students achieve real career results.
Currently leads architecture for ToyCRM.com — a multi-tenant CRM platform built on .NET by our team. The same patterns and design decisions used there appear directly in the courses: identity & auth, distributed services, code review culture. You learn from engineers actively shipping production code, not from a textbook.
Syllabus
Six modules to make spec-driven development the operating model of your team — across any AI stack, on any codebase:
- 1 Module 1: Why spec-driven? — the death of vibe coding; code as cache, spec as truth; the spec→context→evals trinity; auditing your current workflow for the three places you're guessing
- 2 Module 2: The spec hierarchy — system spec, feature spec, task spec, inline spec; what belongs where; writing project.md and your first feature spec for a real feature you own
- 3 Module 3: Writing executable specs — GIVEN/WHEN/THEN, examples and counter-examples, negative specs, the single-capability rule; converting a Jira ticket into an executable spec end-to-end
- 4 Module 4: Context engineering integration — load-on-demand reading, the 40% context-window threshold, hot/warm/cold tiers; mapping your spec→context pipeline and instrumenting token cost per layer
- 5 Module 5: PR review as spec review — change isolation, atomic merges, the death of the 600-line diff, killing code-review fatigue; running a real PR where the spec delta is the reviewable artifact
- 6 Module 6: Where spec-first fails + team adoption — exploratory work, performance-critical paths, legacy archaeology; onboarding teammates; governance; retrofitting brownfield codebases responsibly
Prerequisites
Prompt Engineering (#21) and Claude API (#25) strongly recommended. Any course in the AI/Agents catalog (22, 24, 26) is also a fit.
Comfort writing production code in any modern language. Familiarity with at least one AI coding tool (Claude Code, Cursor, or similar). Basic understanding of LLMs as collaborators, not magic.
What you'll build
You leave able to walk into any brownfield codebase, audit its spec discipline, and ship a spec-driven workflow your team will actually adopt — not the slide-deck version, the one that survives the third sprint.
- Spec hierarchy: system, feature, task, inline
- Writing executable specs with GIVEN/WHEN/THEN
- Context engineering integration: load-on-demand, tiered context
- PR review as spec review — change isolation, atomic merges
- Team adoption and brownfield retrofitting
Where this fits in your career
Read alongside this course
OpenSpec in 2026: The Operating System for Spec-Driven Development
Six weeks ago I installed @fission-ai/openspec. Yesterday I shipped a 14-file change in 90 minutes from a 200-line spec, in a brownfield codebase three engineers have been editing for two years — no merge conflicts, no review escalation. This is the senior-architect deep-dive on why OpenSpec is the first SDD tool that doesn't collapse under production reality.
Evals in 2026: The Test Suite for Systems That Aren't Deterministic
Your AI feature worked yesterday and fails today. No code change, no prompt change, no model change. That's what life without evals looks like. This is the third leg of the spec → context → evals trinity — and the discipline most teams skip.
Spec-Driven Development: When Your Spec Becomes the Codebase
I haven't written a function by hand in two months — and the codebase has never been healthier. Here's how spec-driven development changed what 'engineering work' means in 2026, the rules that keep the discipline honest, and where it still falls apart.
First lesson on us. Decide after meeting your instructor.
Sit in on the first session. If after lesson 1 you decide the instructor isn't the right fit, you don't pay for it — and no awkward conversation. (Trial offer applies to courses with more than 5 lessons; this one qualifies.)
Pricing & what's included
What's included
- 12 live sessions × 2 hours each — taught by the instructor, not a recording playback
- Slide deck for every session — yours to keep and refer back to
- Working code files and any data files used in class — cloned to your machine
- Weekly homework with personal code review from the instructor
- Recording on request — give the teacher a heads-up ("can't make Tuesday, please record it") and the session is recorded for you
Frequently asked questions
How much time per week will this take?
Plan for the live sessions plus roughly 1.5–2 hours of practice per session. Most students who finish on schedule put in 4–6 hours a week total. If you put in less, you still finish — it just takes longer.
What if I miss a class?
Tell the teacher BEFORE the session — "I can't make Tuesday, please record it" — and the teacher records that lesson and sends it to you. Recordings aren't a default catch-up archive; they're produced on request when you give a heads-up. After the lesson you do the homework, bring questions to the next session.
What's included in the price?
Live sessions with the teacher; the slide deck for each session (yours to keep); the working code files and any data files used in class; weekly homework with code review; and recordings of the sessions you give advance notice for. Anything beyond that — a certificate, alumni access, mock interviews — is listed explicitly in "What's included" above the FAQ for the courses where it applies.
What if I sign up and the teacher isn't a fit?
For courses with more than 5 lessons, the first session is effectively a trial — if after lesson 1 you decide the teacher isn't a fit, you don't pay for it. We'd rather you walk away after one lesson than push through 9 weeks of bad chemistry. (Courses with 5 or fewer lessons are short enough that the standard pricing applies — the trial offer doesn't make sense at that length.)
Can I get a refund partway through?
Yes, while more than half the course is still unused — i.e. you've attended fewer than 50% of the lessons. The refund covers the unused portion proportionally. Past the halfway point we don't refund, on the assumption that the value has been delivered.
Can I switch the language of instruction?
The live sessions run in the language listed under "Available Languages" above. Slides and code files are typically available in all four (English, Russian, Ukrainian, Georgian). Many students attend sessions in one language and read materials in another — that's normal.
Will I be ready for a real job after this course?
One course rarely gets anyone hired by itself — for any field. What this course gives you is the foundation a junior hiring manager expects: working code you wrote yourself, the vocabulary to read other people's code, and the practice habits that make you employable. The honest answer to "am I ready?" is on our roadmap (link in the page header) — open the level you want to reach and read the "You're ready when" checklist.
Can I pay in instalments?
Yes for courses with a "Monthly Payment" option in the at-a-glance ribbon — usually two or three equal monthly payments. Courses without that option are paid in one go. If the price is the blocker, write to us — we look at every case.