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.
npx agentmods add instructions/bigdevsoon/100-days-of-code/agents-mdgit clone --depth 1 https://github.com/bigdevsoon/100-days-of-codeWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/bigdevsoon/100-days-of-code/agents-md)<a href="https://agentmods.dev/instructions/bigdevsoon/100-days-of-code/agents-md"><img src="https://agentmods.dev/badge/instructions/bigdevsoon/100-days-of-code/agents-md.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00737 | $0.00737 |
| Opus 5 | $0.00368 | $0.00368 |
| Sonnet 5 | $0.00147 | $0.00147 |
| Haiku 4.5 | $0.00074 | $0.00074 |
Grade A, and why
100-days-of-code AGENTS.md 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AI Agent Guide
This repository is structured for AI-assisted development. Each of the 100 challenges provides the exact context coding agents need - design mockups, user stories, and acceptance criteria.
Challenge Structure
Every challenge folder (day-01 through day-100) contains:
day-XX/
README.md - User story, acceptance criteria, tips
design.png - Professional design mockup to replicate
index.html - Starter HTML file
The README includes:
- User Story - Who the user is and what they need
- Acceptance Criteria - Specific, testable requirements
- Design Preview - Screenshot of the target UI
How to Use with AI Agents
Provide Full Context
When starting a challenge, give your AI agent:
- The user story and acceptance criteria from the README
- The design mockup image (if your agent supports vision)
- Your preferred tech stack (React, Vue, vanilla JS, etc.)
Example prompt:
I'm building the "Profile Card" challenge. Here are the requirements:
User Story: As a user, I want a profile card that showcases my professional
details and personality, making it easy for viewers to connect with me.
Acceptance Criteria:
- Profile image in a dynamically shaped frame
- Name, username, and professional bio displayed clearly
- Functional social media icons
- Responsive Follow and Message buttons
- Works across different screen sizes
Build this with React and Tailwind CSS. Start with the component structure.
Iterate, Don't Generate Everything at Once
Break the work into steps:
- Component structure and layout
- Styling to match the design
- Interactivity and state management
- Responsive design adjustments
- Accessibility and edge cases
Validate Against Acceptance Criteria
After building, have your agent review each criterion:
Check our implementation against each acceptance criterion.
What's missing or incomplete?
Challenge Categories
Components (Days 1-20) - Cards, forms, navigation, carousels. Good for learning layout and styling.
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.
- 5d ago First seen · 87 lines · 737 tokens per session scan A fc4c019339d2
100-days-of-code AGENTS.md is an instructions file published in the GitHub repository bigdevsoon/100-days-of-code (74 stars, last pushed 6mo ago), licensed MIT. It adds 737 tokens to every session, about $0.0037 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.
Other instructions, from other repositories
electron CLAUDE.md
Instructions for electron/electron, covering electron development guide, running nodemodules binaries, project overview, directory structure and build tools setup.
electron copilot-instructions.md
Instructions for electron/electron, covering copilot instructions for electron, build system, linting, running a single test and example: npm run test -- -g "ipc".
html-video CLAUDE.md
Instructions for nexu-io/html-video, covering html-video 项目工作区, 角色与边界, 产品定位（决策时间线）, 关键差异化 vs hyperframes and 目录结构.
skelet AGENTS.md
Instructions for Selekkt/skelet, covering agents.md — developing skelet.css, what skelet is, source of truth, repo map and rules of engagement (framework dev).
mis-recursos-webdev AGENTS.md
AGENTS.md instructions for Alplox/mis-recursos-webdev, covering agents.md — mis recursos web dev, 📋 stack, 🏗️ estructura del proyecto, 🧠 source of truth and estructura del readme.
starling AGENTS.md
Instructions for starling-browser/starling, covering agents — rules of engagement, tl;dr, 1. orient, 2. claim something unblocked and 3. read the package file and start working on main.