Codex Full Course 2026: The NEW Best AI Coding Tool

Tech-focused summary (Codex Full Course 2026)

What Codex is (product concept)

• A unified AI “agent tool” that combines multiple workflows in one interface:
  • Coding + file operations (create/edit/delete on your computer)
  • Browser/search/research (web search to gather info)
  • Computer control (“computer use”) for mouse/keyboard automation
  • Document creation (e.g., spreadsheets, docs, slide decks)
• Uses Projects with a local folder/file-path so the agent can:
  • Organize outputs
  • Keep work referencable
• Built-in emphasis on multitasking / parallel work, allowing multiple chats/tasks to run concurrently.

Core onboarding / UI workflow

• Download/install the Codex desktop app (macOS mentioned).
• App structure includes:
  • A left panel with multiple modes/options (exactly 5 items mentioned earlier)
  • A chat interface similar to ChatGPT, but with agent + tools + outputs
  • A new “chats column” behavior for organizing chats under the correct location/project
• Projects = folders on disk
  • Recommended: set a specific start location for each project so created files land in the right place.
  • Agent-created file outputs appear under an outputs folder inside the project location.
• Multichat concurrency inside one project
  • Example: run research chats simultaneously and track progress via UI indicators (spinners/blue dot).
  • After one response finishes, you can issue follow-ups like: “create a spreadsheet from what you told me.”

Prompting basics + agent controls

• Key settings mentioned:
  • Permissions: agent actions may require approval; instructor prefers full access
  • Model selection (example shown: GPT 5.4)
  • Effort level (example: “extra high” default)
• Agent file insertion:
  • Use @mentions to reference files later (e.g., “@Codex desktop features”).
• Views:
  • Files can be opened in a side view or full screen.
  • The agent can iteratively modify artifacts (e.g., remove columns from an xlsx).

Organization tools: Search + chat management

• Codex includes a search feature to find chats by name across stored work.
• Chats/projects can be removed from the side panel without deleting local data (folders remain on disk), then re-added later.

Skills vs Plugins (extension architecture)

• The video explains a conceptual distinction:
  • Skills = reusable “workflow packages/recipes” for tasks
  • Plugins = installable units that extend capabilities
• Instructor note: terminology can feel blurry across ecosystems; OpenAI uses plugins/skills naming.
• Example: Google Calendar plugin
  • Install → sign in → connected
  • Agent can then:
    • List events
    • Send weekly recap emails via Gmail
    • Turn results into scheduled automations

Automations

• Automations can be created via natural language:
  • Example: “weekly calendar recap every Friday at 4:00 p.m.”
• Automations can be:
  • Tested
  • Edited
  • Managed with metadata like active status and next run time
• Automations can reference specific skills (e.g., YouTube Researcher + word doc skill).

Plugin integrations: Figma + “Paper” design workflow

• Figma plugin capabilities described:
  1. Inspect existing Figma files
  2. Generate new visual artifacts
  3. Connect Figma to code bases
• Demonstrated flow included generating a “hello world” and then building a landing page.
• Instructor argues Paper is a more effective design pipeline than direct Figma-plugin prompting:
  • Uses an MCP (Model Context Protocol) approach (“Paper MCP”)
  • Designed to make producing multiple variations in parallel smoother
• Steering / message queuing while the agent runs
  • Instead of waiting for completion, “steer” lets new instructions apply mid-task
  • Example: fix overlapping CTA buttons while design generation continues

Creating custom skills (and using external APIs)

• Video shows building a skill wrapper around an external API.
• Example: “YouTube Researcher” skill using the Super Data transcript API
• Steps:
  • Find tool/API
  • Get an API key
  • Use a skill creator prompt to generate a reusable skill
• Skill can then:
  • Fetch latest channel videos
  • Pull transcripts
  • Summarize into a document
  • Perform “hook analysis” (what intros/hooks performed best/worst)
• Report output includes:
  • “Hook winners” and “hook losers”
  • A recommendation for what to double down on
• Then the skill is paired with word doc generation and used in monthly automation.

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Part 2: Role-play “build an AI business” with multitasking (6 outputs in parallel)

Scenario

• Builds “Chorus”:
  • A learning app for AI agents
  • Includes a skills library curated for reuse/copy-paste
• Workstreams described as running/iterating concurrently:
  1. Markdown plan (one-pager)
  2. iOS app (Swift)
  3. Web app landing page + waitlist form
  4. Investor deck (PowerPoint)
  5. Launch video (Remotion motion graphics)
  6. Social distribution automation (X/Twitter via Typefully)

Multitasking strategy (“serial tasking”)

• Focus on one agent task per prompt, then switch to another chat while the previous continues running.

iOS app generation with Codex + Xcode + Simulator

• Requirements mentioned:
  • Mac + Xcode
  • iOS simulator
• Codex workflow:
  • Generate initial Swift project
  • Open in Xcode
  • Run on iPhone simulator (example: “iPhone 17”)
• Screens built via a “mobile design skill”:
  • Described as extracted/mimicked from Anthropic’s design workflow
• Integration approach:
  • Codex can generate screens, then “integrate screens” into the Swift project
• Iterative UI polish:
  • Example requests: pinned titles, fading list behavior, bottom tab bar styling
• Image generation:
  • Codex generates 10 iOS app icons (no background) in a consistent style

Landing page waitlist with Tally + React shell

• Uses tally.so to create a waitlist form (first/last/email).
• Embeds the form into a web app generated by Codex.
• Workflow:
  • Generate minimal landing page shell
  • Insert Tally embed code
  • Deploy the site (Vercel)

Database + auth with Supabase (via MCP)

• Database recommendation: Supabase Postgres
• Since no official Supabase plugin was shown, Codex searches for a Supabase skill.
• Video shows:
  • Creating a Supabase project
  • Enabling features like data API / MCP client support
  • Applying schema/tables via database update
  • Verifying via the Supabase table editor (tables like platforms/categories/saved/skills referenced)
• Authentication:
  • Initially asked for Google OAuth, later switched to email/password
  • Confirm-email behavior adjusted (turning off confirm email during the demo)
  • After auth, saving skills/platforms/tracks to the DB

Motion graphics launch video with Remotion

• Uses a Remotion plugin/skill to generate/edit motion graphics from prompts.
• Example generation details:
  • Local Remotion server link (localhost with a timeline UI)
  • Edits described with time/frame precision (30fps)
  • Iteration on mouse/cursor positioning using grid/ruler hacks when the pointer misses targets
• Instructor builds sequences/scenes:
  • Opening statement (“Agents are taking over the world”)
  • “Learn” screen transition
  • “Skills” section with multiple learnable items (winners/lessons concept)

Design refinement: Claude Code for web/presentation aesthetics

• Instructor claims Codex may be weaker at web design/visual polish.
• Uses Claude Code (via terminal) to restyle:
  • Landing page conversion-focused design
  • Investor deck refinement (“less text, more visuals”)
  • Logo/icon placement (where possible)
• Export to Canva:
  • Investor deck generated in Codex can be opened in Canva for final touches.

Social automation with Typefully

• Creates a Typefully skill using the v3 API:
  • Goal: control multiple X accounts and draft posts with AI
• Sets up an automation:
  • “three drafts every morning”
• Typefully drafts are created autonomously and stored as draft content (confirmed in Typefully UI).

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Reviews / guides / tutorials called out

• This is primarily a complete guide/course:
  • Part 1: prompting basics, permissions, models/effort, projects, file outputs, organization (search), skills/plugins, automations, and computer use.
  • Part 2: multitasking role-play: build iOS + web + investor deck + launch video + social automation.
• Tutorial-style steps include:
  • Installing Codex desktop app
  • Creating projects and locating outputs in Finder
  • Using “@file” references
  • Installing plugins (e.g., Google Calendar)
  • Creating automations
  • Building custom skills using external APIs (Super Data, YouTube transcript workflow)
  • Using MCP-based integrations (Paper MCP)
  • Using Remotion for motion graphics
  • Using Supabase Postgres + auth (email/password) via MCP-based skills
  • Deploying web app via Vercel
  • Integrating Tally embeds into React web shells
  • Exporting slide decks to Canva
  • Creating Typefully API skill and X posting automation

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Main speakers / sources (end)

• Main speaker/source: “Riley Brown” (instructor; referenced repeatedly as the channel/app creator)
• Systems/tools referenced: OpenAI Codex (Codex desktop app), GPT-5.4, Super Data, Google Calendar/Gmail, Figma, Paper (Paper MCP), MCP, Xcode/iOS Simulator, Supabase, Remotion, Tally, Vercel, Claude Code / Claude, Canva, Typefully, WhisperFlow, Opus (Claude-based)