Codeck

Markdown presentations for macOS and Codex.

Write plain-text .mdeck presentations, preview slides as you edit, and present fullscreen. Use the native Mac app or the Codeck workspace inside Codex. Run live Codex prompts from slides, and review proposed Markdown edits with the Mac app's Deck Assistant.

Why Codeck

Most presentation tools separate the script, the source material, the live demo, and the AI assistant into different windows. Codeck brings those pieces into one native Mac loop:

• Write in Markdown: Decks are plain-text .mdeck files with YAML front matter and --- slide separators.
• Preview as you work: The editor, slide list, and rendered presentation view stay together.
• Run Codex from a slide: Fenced codex blocks become live prompt cards with model, reasoning, and sandbox settings.
• Improve a deck with Codex: The Deck Assistant can review one slide or the whole deck and return selectable insertions and replacements.
• Present without exporting: Start full-screen presentation mode from the selected slide.
• Let agents edit decks: Use the file-based MCP server or live app bridge to create, inspect, and mutate decks programmatically.

What You Can Build

• AI training decks: Teach prompting, evaluation, code review, or agent workflows with runnable examples on the slide.
• Live demo talks: Keep the prompt, context, expected behavior, and streamed Codex response in the same artifact.
• Executive briefings: Draft a rough narrative, ask the Deck Assistant to sharpen it, add evidence, and apply only the changes you trust.
• Research and product narratives: Use Markdown, tables, links, images, citations, and web-backed assistant passes to keep claims grounded.
• Workshops and exercises: Build decks where each slide can ask Codex to inspect, explain, test, or transform something live.
• Agent-editable documentation: Give another MCP-capable agent a .mdeck file or an open Codeck window and let it insert slides, update settings, or validate the deck.

Core Features

• Native macOS document app for .mdeck files.
• Codex plugin with its own sidebar workspace, split Markdown editor and preview, native Codex composer, and fullscreen presentation.
• Markdown slides with headings, lists, blockquotes, tables, links, images, GIFs, and fenced code blocks.
• Syntax highlighting for common code fence languages.
• Theme picker with Studio, Midnight, Chalk, Solar, and Atelier presentation themes.
• Sidebar for scanning, selecting, adding, duplicating, deleting, and organizing slides.
• Live preview beside the editor, plus compact modes for smaller windows.
• Insert tools for common Markdown blocks, images, tables, and Codex cards.
• Deck-level Codex defaults for model, reasoning effort, and sandbox.
• Per-slide live Codex cards, per-card overrides, streaming Markdown output, and run-all on slides with multiple sessions.
• Deck Assistant with Slide and Deck scopes, quick actions for Find Gaps, Shorten, Polish, Research, and Add Data, optional web use, selectable changes, and one-click apply.
• Full-screen presentation mode with keyboard navigation.
• File-based MCP server for deck automation outside the app.
• Live localhost MCP bridge for agents that need to work with currently open Codeck windows.

Install the Mac app