# Preview Markdown in Finder with Quick Look. Select a Markdown file in Finder and press Space. With MarsDawn installed, Quick Look shows the rendered page instead of plain text. ## What the preview shows - The rendered page, drawn by the same renderer as MarsDawn's preview pane. - Mermaid diagrams, KaTeX math and highlighted code blocks. - The preview theme you picked in MarsDawn, in light or dark. - Web images stay blocked, and pictures stored next to the file can appear as placeholders. ## How to preview a Markdown file with Quick Look 1. **Install MarsDawn.** Download MarsDawn from the Mac App Store. The Quick Look extension is part of the app. 2. **Select a Markdown file.** In Finder, click a .md file once. 3. **Press Space.** The rendered preview opens. Press Space again to close it. 4. **If you see plain text, switch the extension on.** Open System Settings, go to General ▸ Login Items & Extensions, click the Info button next to Quick Look under Extensions, turn on MarsDawn Preview, then click Done. ## Not locked by the trial Quick Look keeps working after the trial ends. It shows the same rendered preview while the trial runs, after it ends and after you unlock. After the trial ends and until you unlock, MarsDawn's own windows open with their content covered; Finder previews are unchanged. The [trial and unlock page](/pay-once/) sets all three stages side by side. ## Questions and answers ### How do I preview a Markdown file in Finder? Select the file and press Space. With MarsDawn installed, Quick Look shows the rendered page, with Mermaid diagrams, KaTeX math and highlighted code. ### Does Quick Look still work after the 14-day trial? Yes. Quick Look is not locked by the trial. It keeps rendering Markdown files while the trial runs, after it ends and once you unlock. ### Why does Quick Look show plain text? The Quick Look extension may be switched off. Open System Settings, go to General ▸ Login Items & Extensions, click the Info button next to Quick Look under Extensions, turn on MarsDawn Preview, then click Done. ### Does Quick Look cost extra? No. The Quick Look extension is part of MarsDawn, with no separate purchase. MarsDawn is a free download with a 14-day trial and a one-time USD 4.99 unlock, and Quick Look works with or without the trial. ### Which version of macOS does it need? MarsDawn needs macOS 26 or later. ## Next - [A Mac app](/native/) - [Try free, pay once](/pay-once/) - [How to open .md files on Mac](/view-markdown-on-mac/) ## More - [MarsDawn](https://marsdawn.southern-light.dev/index.md): Read and review the Markdown your agent wrote, natively on Mac: live split preview, Mermaid, KaTeX, Quick Look, PDF export. Free to try, USD 4.99 once. - [Features](https://marsdawn.southern-light.dev/features/index.md): A native Mac Markdown editor: live preview, Mermaid and math, themes, plus clean PDF and print pages for meetings, margin notes and paper records. - [Your writing stays on your Mac](https://marsdawn.southern-light.dev/yours/index.md): MarsDawn has no account, no sync and no cloud. Your Markdown documents stay on your Mac, in the files and folders you choose. - [Try free, pay once](https://marsdawn.southern-light.dev/pay-once/index.md): MarsDawn is free to download. Try everything for 14 days, then unlock it once for USD 4.99. No subscription, no account. - [PDF export](https://marsdawn.southern-light.dev/pdf/index.md): Export Markdown as a PDF or print it on your Mac, with Mermaid diagrams and highlighted code. Page breaks avoid splitting short code blocks. - [A Mac app](https://marsdawn.southern-light.dev/native/index.md): A Markdown editor that is a real Mac app: native windows and tabs, autosave, version history, Quick Look in Finder and a text editor that behaves like a Mac. - [What MarsDawn doesn't do](https://marsdawn.southern-light.dev/limits/index.md): No sync, no editing on iPhone or iPad, no plugins, no accounts. Themes, but no custom CSS. Know before you buy. - [Support](https://marsdawn.southern-light.dev/support/index.md): Get help with MarsDawn, the Markdown editor for macOS. - [Privacy Policy](https://marsdawn.southern-light.dev/privacy/index.md): MarsDawn does not collect personal data. Your documents and settings stay on your Mac. - [How to open .md files on Mac](https://marsdawn.southern-light.dev/view-markdown-on-mac/index.md): How to open a .md file on a Mac: double-click, set a default app, preview in Finder. For .md files an AI agent wrote, read them rendered in MarsDawn. - [Mermaid preview on Mac](https://marsdawn.southern-light.dev/mermaid-preview-mac/index.md): See Mermaid diagrams drawn next to your Markdown on a Mac: live preview, Quick Look and PDF export. A broken diagram shows its error and the line. - [Markdown to PDF](https://marsdawn.southern-light.dev/markdown-to-pdf/index.md): Convert Markdown to PDF on a Mac with the free marsdawn command-line tool. Install it with Homebrew and run one command: tables, math, Mermaid and code. - [MarsDawn compared: VS Code preview, Obsidian, QLMarkdown, LynxOffice](https://marsdawn.southern-light.dev/vs/index.md): For anyone choosing how to read and review Markdown on a Mac, often what an agent wrote. Every cell below comes from the vendor's own pages or our own check, all on 16 October 2026; products change, so a cell can go stale. If you spot a mistake, write to the address on Support. - [MacMD Viewer vs. MarsDawn](https://marsdawn.southern-light.dev/vs/macmd-viewer/index.md): MacMD Viewer is a read-only Markdown viewer for USD 19.99. MarsDawn edits and previews side by side: free for 14 days, then USD 4.99 once. - [Best Markdown viewer for Mac (2026)](https://marsdawn.southern-light.dev/best-markdown-viewer-mac/index.md): Eight Markdown viewers for Mac compared by price, Mermaid, math, PDF, live reload, Quick Look and native vs Electron, with who each one suits. - [Command Line](https://marsdawn.southern-light.dev/cli/index.md): The free marsdawn command-line tool for Mac: export Markdown to PDF from a shell, a script or an LLM agent, with JSON output. Install it with Homebrew. - [marsdawn for agents](https://marsdawn.southern-light.dev/cli/agents/index.md): A reference for AI agents and scripts that call marsdawn to turn Markdown into PDF: commands, JSON output, schemas, exit codes and requirements. - [Agent skill](https://marsdawn.southern-light.dev/cli/skill/index.md): One file your coding agent loads to open Markdown it wrote in MarsDawn for your review, and to install marsdawn, export Markdown to PDF and read the JSON result. - [MCP server](https://marsdawn.southern-light.dev/cli/mcp/index.md): marsdawn has no AI model of its own, so it doesn't matter which agent wrote the Markdown. Call it from the CLI, a skill file, or the marsdawn-mcp MCP server: all three run the same export. - [Token-efficient review](https://marsdawn.southern-light.dev/token-efficient-review/index.md): A person reviews the rendered page in MarsDawn, never read back into the agent's context. The tool call itself returns a compact JSON result, not the rendered content, so calling it is cheap too. - [Viewing Markdown elsewhere vs. MarsDawn](https://marsdawn.southern-light.dev/vs/markdown-preview-tools/index.md): How MarsDawn compares to reading Markdown in VS Code's built-in preview, a browser extension, or Claude Desktop's file preview: what each renders, and what it takes to open one file. - [Themes](https://marsdawn.southern-light.dev/themes/index.md): Four built-in preview themes, each light and dark, plus a curated gallery you open from Settings in MarsDawn for Mac. Quick Look uses your theme. - [Build a theme](https://marsdawn.southern-light.dev/themes/new/index.md): Pick colours and a handful of style options, see them applied to a sample document live, and submit your theme as a GitHub issue. No install, no git. - [Make a theme with your agent](https://marsdawn.southern-light.dev/themes/agents/index.md): MarsDawn theme reference for AI agents: each theme.json field with type and range, the CLI loop that checks and renders it, a hand-off link, and how to submit. - [Theme gallery](https://marsdawn.southern-light.dev/themes/gallery/index.md): Browse preview themes for MarsDawn, each reviewed by the developer, filter them by scenario, and report a problem with one. Build your own in the browser. - [Sharing exported PDFs](https://marsdawn.southern-light.dev/sharing-exported-pdfs/index.md): Export an agent's Markdown to PDF and hand it to a colleague who doesn't read Markdown and won't install anything. No syntax, no app and no account needed to open it. - [Why AI output still needs a human reader](https://marsdawn.southern-light.dev/reviewing-ai-output/index.md): AI-written Markdown still has to be understood by a person, not trusted on sight. MarsDawn pairs the rendered page with the source, and draws Mermaid diagrams and KaTeX math, so structure is legible at a glance. - [Reading what your agent hands back](https://marsdawn.southern-light.dev/reading-agent-output/index.md): AI agents hand back their work as Markdown: plans, specs, progress reports. What people who build agents say about checkpoints and failures, why that output is hard to read, and a five-minute checklist for reviewing a plan. - [Agent transparency](https://marsdawn.southern-light.dev/agent-transparency/index.md): Anthropic's guide to building agents asks for transparency: show the planning steps. What it says, what it doesn't, and why the steps usually end up as a Markdown file someone has to read. - [Reviewing an agent plan](https://marsdawn.southern-light.dev/reviewing-agent-plans/index.md): A six-step way to review the plan an AI agent hands you before it runs, in about five minutes and in any editor, with a worked example. - [Agent design patterns](https://marsdawn.southern-light.dev/agent-design-patterns/index.md): Reflection, tool use, planning and multi-agent collaboration, as Andrew Ng described them, and what each tends to hand back for you to read. - [Changelog](https://marsdawn.southern-light.dev/changelog/index.md): What changed in each version of the MarsDawn app and the free marsdawn CLI. - [Roadmap](https://marsdawn.southern-light.dev/roadmap/index.md): What's in progress and what's next for MarsDawn on Mac, iPhone and iPad, by version. No dates, and unscheduled ideas are marked. - [Editor's reading notes](https://marsdawn.southern-light.dev/reading-notes/index.md): Six short notes on what the people building AI agents actually argue — Anthropic, Chip Huyen, Lilian Weng, Harrison Chase, LangChain and Andrew Ng — and what each one means for the person who has to read what such an agent hands back. - [Reading notes: Anthropic](https://marsdawn.southern-light.dev/reading-notes/anthropic-building-effective-agents/index.md): Anthropic's December 2024 guide for people building agents separates workflows from agents and describes five workflow patterns, including one where a second LLM call reviews the first. What that means for what lands in your folder. - [Reading notes: Chip Huyen](https://marsdawn.southern-light.dev/reading-notes/chip-huyen-agents/index.md): Chip Huyen's January 2025 essay on agents splits their actions into read-only and write actions. Why that split is a fast way to spot the line in a plan worth a closer look before you approve it. - [Reading notes: Lilian Weng](https://marsdawn.southern-light.dev/reading-notes/lilian-weng-llm-agents/index.md): Lilian Weng's widely cited 2023 survey describes an LLM agent as a brain plus planning, memory and tool use. What each part tends to leave behind for you to read, and the limitation she names in plans that don't adjust to surprises. - [Reading notes: Harrison Chase](https://marsdawn.southern-light.dev/reading-notes/harrison-chase-what-is-an-agent/index.md): Harrison Chase's 2024 definition of an agent and his spectrum of agentic behavior, and his case for observability as a system moves along it — read from the side of whoever reads the file it hands back. - [Reading notes: LangChain (Jess Ou)](https://marsdawn.southern-light.dev/reading-notes/langchain-what-is-an-agent/index.md): LangChain's 2026 “What is an AI agent?” by Jess Ou echoes Harrison Chase's 2024 definition and describes a pipeline for evaluating agents automatically. Where that pipeline still hands a step to a person, and where it doesn't. - [Reading notes: Andrew Ng](https://marsdawn.southern-light.dev/reading-notes/andrew-ng-design-patterns/index.md): Across five letters in The Batch, Andrew Ng ranks reflection, tool use, planning and multi-agent collaboration by how reliable and predictable he finds each one — and what that ranking suggests about how closely to check each one's output. - [Templates](https://marsdawn.southern-light.dev/templates/index.md): Markdown templates for the documents an agent writes and you read: a spec, a flowchart and meeting notes, each with a prompt for your agent. - [Spec template](https://marsdawn.southern-light.dev/templates/spec/index.md): A Markdown spec template with requirements, a Mermaid flow diagram and acceptance criteria. Your agent fills it in; you review it in MarsDawn. - [Flowchart template](https://marsdawn.southern-light.dev/templates/flowchart/index.md): A Mermaid flowchart template in Markdown, with the steps written out below it. Preview it on a Mac and export it to PDF. - [Meeting notes template](https://marsdawn.southern-light.dev/templates/meeting-notes/index.md): A Markdown meeting notes template with decisions and action items, each with an owner. Your agent writes it up; you check it in MarsDawn. - [繁體中文](https://marsdawn.southern-light.dev/zh-hant/quicklook/index.md): MarsDawn 的快速查看讓你在 Finder 按空白鍵就看到排版後的 Markdown，Mermaid 圖表、KaTeX 數學式和程式碼上色都在。試用期結束後，快速查看照常可用。 - [简体中文](https://marsdawn.southern-light.dev/zh-hans/quicklook/index.md): MarsDawn 的快速查看让你在访达按空格键就能看到排版后的 Markdown，Mermaid 图表、KaTeX 数学公式和代码高亮都在。试用期结束后，快速查看照常可用。 - [日本語](https://marsdawn.southern-light.dev/ja/quicklook/index.md): MarsDawn のクイックルックなら、Finder でスペースキーを押すだけで Markdown を描画して表示します。Mermaid 図、KaTeX 数式、ハイライトされたコードにも対応。トライアル終了後も使えます。 - [Deutsch](https://marsdawn.southern-light.dev/de/quicklook/index.md): Mit MarsDawn zeigt die Übersicht Markdown im Finder per Leertaste gerendert: Mermaid, KaTeX, hervorgehobener Code. Sie funktioniert auch nach dem Test weiter. - [Français](https://marsdawn.southern-light.dev/fr/quicklook/index.md): Avec MarsDawn, Coup d’œil affiche le Markdown mis en forme dans le Finder avec Espace : Mermaid, KaTeX, code coloré. Il fonctionne toujours après l’essai. - [Español](https://marsdawn.southern-light.dev/es/quicklook/index.md): Con MarsDawn, Vista rápida renderiza Markdown en el Finder con la barra espaciadora: Mermaid, KaTeX y código resaltado. Sigue funcionando tras la prueba. - [한국어](https://marsdawn.southern-light.dev/ko/quicklook/index.md): MarsDawn의 훑어보기로 Finder에서 스페이스 바를 누르면 Markdown이 렌더링되어 보입니다. Mermaid, KaTeX, 강조된 코드도 표시됩니다. 체험이 끝난 뒤에도 계속 작동합니다.