CodeTrain / Docs
CodeTrain documentation
Everything published about how CodeTrain works, in one place. Pick the section that matches what you are doing.
When to use CodeTrain
Reach for CodeTrain when the goal is that a person ends up able to do the work, and reach for something else when the goal is that the work gets done.
Good fits:
- A developer has to learn an unfamiliar codebase, and reading a summary of it will not survive contact with the first ticket. Point CodeTrain at the repository and it teaches from the code that is really there.
- A team lead needs evidence of what an engineer can do without help, for onboarding, for a promotion case, or after a stretch of heavy AI assistance. CodeTrain records unaided completion per step and reports "no data" rather than zero when nothing assessable happened.
- Somebody wants to learn a specific concept by writing it rather than watching it. Name the topic and a lesson is written on the spot.
- You want a stepwise lesson generated from any public repository, with secrets and ignored files refused rather than read.
- A developer already works in Claude Code, or in OpenCode, and wants a tutor inside it. CodeTrain Open Skill, free and open source, installs with
npx skills add InferHaven/agent-skills --skill codetrain: same rule that you write every line, no account. See CodeTrain Open Skill.
Bad fits, and we would rather say so:
- You want the code written. CodeTrain will not do it, by design and with a code-level guard on top of the prompt rule. Use a coding assistant.
- You want a video course, a quiz, or a certificate. There are none.
- You want to grade somebody without their knowledge. Every record here is attached to work the person did in front of them.
Which CodeTrain is which?
CodeTrain is one product with one account, and there are two ways in today: the website at codetrain.ai and the CodeTrain CLI on your own machine. CodeTrain Open Skill is a separate, free tool that needs no account.
| Best for | Who teaches | Where your code goes | Account needed | |
|---|---|---|---|---|
| CodeTrain website (codetrain.ai) | Learning in your browser, on any topic you name, on any public GitHub repository, or from curated courses. The homepage also runs a real lesson with no account. | CodeTrain's tutor, which writes the lesson. | Python and JavaScript run in your browser; languages a browser cannot run, such as bash, run on CodeTrain's servers. Code you submit, and files you attach, reach CodeTrain's servers and the model provider, and are stored in your lesson. | A CodeTrain account, with a free plan and no card. |
| CodeTrain CLI | Working on the repository in your current folder, or on a practice project, from your own machine. | CodeTrain's tutor, running on your machine and serving its interface on 127.0.0.1. | Your repository stays on your machine: the CodeTrain CLI reads the checkout in place, and only the prompt snippets needed for one tutoring turn go to the model provider. CodeTrain never copies or stores the repository. Lessons stay in your project folder. | Signs in to your CodeTrain account, and your plan's limits apply. With your own model key in its config file, model calls go straight to your provider. |
| CodeTrain Open Skill | Learning inside the coding agent you already use, such as Claude Code or OpenCode. | Your agent's own model, teaching with CodeTrain's method: you write every line, and it sets the steps, gives hints and reviews your work. | The lesson page runs on 127.0.0.1. Your agent sends what it reads, your code included, to its own model provider, as it does for any task. Python runs in your browser. | No account, and nothing goes to CodeTrain: no telemetry either. Free and open source, Apache 2.0. |
Using the product
- The homepage runs a real lesson in the browser with no account. It is the fastest way to see what a step looks like and what happens when your code does not pass.
- The course catalog lists every curated course and class. These are the starting point rather than the product: the tutor writes a lesson on any topic you name, or on any public repository you paste.
- How the Socratic method works here is the exact contract the tutor keeps, quoted from the code that enforces it.
- Learning an unfamiliar codebase covers repo mode and what it refuses to read.
- CodeTrain Open Skill is the free, Apache 2.0 tutor you install into your own coding agent. It covers the install, what was tested where, and what leaves your machine.
Building against CodeTrain
- Developer API: the public REST endpoints, rate-limit headers, the versioning policy, and how to install the command line tool.
- /llms.txt: when to reach for CodeTrain, and every page as markdown. Read this first if you are an agent.
- Any page on this site serves markdown to a client that asks for it with
Accept: text/markdown.
Trust and data
- Security and data handling: where your code goes, what is stored, and how to report a vulnerability.
- Privacy policy: what we collect and how to have it deleted.
- Terms of service.
- About CodeTrain and how to reach a person.
What is changing
- Changelog: what shipped and when, newest first.
- Roadmap: what is being built, what is next, and what we are still thinking about. Shipped items link to the changelog entry that proves it.
- Comparisons: CodeTrain against five categories, general AI study modes, AI coding assistants, coding course platforms, AI course builders, and AI onboarding tools, with each page conceding where the other category wins. Two comparison pages name real products: a roundup of Socratic AI coding tutors, and alternatives to Copilot and Cursor for learning.
- Conductor Network: the affiliate program. What a referral earns, what the rate ladder pays, and how payouts work.