fundamentals

A teaching guide for explaining basic programming ideas, including variables, functions, decisions, loops, and data types. It is designed for CodeSensei explanations aimed at people learning programming fundamentals.

In plain words
What is it for?
Use it when teaching or explaining introductory programming structures, such as storing values, defining reusable actions, and choosing between alternatives.
Why use it?
It helps explain beginner concepts in everyday language and addresses common misunderstandings about how code works.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/dojocodinglabs/code-sensei/fundamentals
Any agent
npx skills add DojoCodingLabs/code-sensei --skill fundamentals
Clone the repo
git clone --depth 1 https://github.com/DojoCodingLabs/code-sensei

Made for: Claude Code, Codex.

Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 595 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00042 $0.00595
Opus 5 $0.00021 $0.00298
Sonnet 5 $0.00008 $0.00119
Haiku 4.5 $0.00004 $0.00060

Measured 2d ago against content hash f1aa23aedb42, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fundamentals scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

skills/fundamentals/SKILL.md · 46 lines

How it starts

The opening of the file, as written. The whole thing — 46 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Programming Fundamentals — CodeSensei Teaching Module

When explaining fundamental programming concepts to the user, use these guidelines:

Variables

  • Analogy (beginner): A labeled box that holds something. The label is the name, the content is the value.
  • Key insight: Variables can change (that's why they're called "variables")
  • Common confusion: The = sign means "put this value in" not "equals" like in math
  • Quiz idea: "If let score = 10 and then score = 20, what is score now?"

Functions

  • Analogy (beginner): A recipe. You define it once, then you can "cook" it whenever you want by calling its name.
  • Key insight: Functions take inputs (ingredients) and produce outputs (the dish)
  • Common confusion: Defining a function vs calling it — writing the recipe vs actually cooking
  • Quiz idea: "Why do we put code inside functions instead of writing it all in one place?"

Conditionals (if/else)

  • Analogy (beginner): A fork in the road. If the condition is true, go left. Otherwise, go right.
  • Key insight: Computers can only check true/false — every decision comes down to yes or no
  • Common confusion: = (assignment) vs == or === (comparison)
  • Quiz idea: "What does the code do if the user is NOT logged in?"

Loops

  • Analogy (beginner): A factory assembly line that repeats the same steps for each item
  • Key insight: Loops save you from writing the same code 100 times
  • Common confusion: Infinite loops — when you forget to change the condition, the loop never stops
  • Quiz idea: "If we have 5 users and loop through them, how many times does the code inside run?"

Data Types

  • Analogy (beginner): Different kinds of containers — a number is a calculator display, a string is a text message, a boolean is a light switch (on/off)
  • Key insight: Computers need to know what TYPE of data they're dealing with to process it correctly
  • Common confusion: The number 42 vs the text "42" — they look the same but the computer treats them differently

Read the full file on GitHub · 46 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 46 lines · 42 tokens per session scan A f1aa23aedb42

Subscribe to this mod's changes

fundamentals is a skill published in the GitHub repository DojoCodingLabs/code-sensei (14 stars, last pushed 2mo ago), licensed MIT. It adds 42 tokens to every session and 595 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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