What it does

The MSI ships a second binary called mdview and adds it to your per-user PATH. From any new PowerShell, cmd, or Git Bash session you can:

• mdview README.md — open a single file.
• mdview . — open the current folder as a workspace, file tree in the sidebar.
• mdview C:\projects\notes — open any folder the same way.
• git diff | mdview — render whatever’s on stdin as an ephemeral markdown document.
• cat NOTES.md | mdview — same idea, anything you can pipe.
• mdview - — explicit stdin form, useful in scripts.

If MD View is already running, every invocation routes to the existing window via single-instance handoff — you don’t end up with five windows on your taskbar. If it isn’t running, the first command boots it.

Why it exists

The file dialog is friction. A markdown CLI tool on Windows lets you stay in your shell — cd, git, grep, ls — instead of alt-tabbing to a file dialog every time you want to read what your agent just wrote. The CLI lets you stay in flow: review what your agent wrote, pipe a diff, scan a folder, all without leaving the terminal context you were already in.

The piping form especially exists because so much AI output ends up in the shell now: logs from claude code, descriptions from gh pr view, generated specs from build scripts. Letting any of that pipe into MD View as a rendered document — without writing a temp file — is the difference between “I’ll read this later” and “I’ll read this now.”

How to use it

After installing MD View from the MSI, open a new shell. The mdview command is on PATH globally. The basic form is mdview <file|folder|.>. Stdin works automatically when MD View detects piped input; you can also force it with --stdin or -.

Under the hood

mdview.exe is a console-subsystem binary, separate from the GUI binary md-view.exe. Console subsystem matters because GUI binaries can’t read stdin or write to a parent shell — Windows splits them at the OS loader level. So MD View ships both: GUI for the window, console for the CLI shim.

Single-instance routing uses tauri-plugin-single-instance. The first invocation acquires a named lock; later invocations detect the lock, send their arguments over a local socket to the running primary, and exit immediately. The primary handles whatever was sent — open the file, switch to workspace mode, render the stdin payload. The lock is per-user, so multiple users on the same machine each get their own primary.

Stdin documents use the internal sentinel DocumentPayload.path === "<stdin>". The watcher and recents subsystems both check for this sentinel and skip stdin docs — they’re ephemeral by design.

Use cases

• Review AI agent output without alt-tabbing: claude code generate-spec | mdview — the spec opens in MD View while your terminal stays focused.
• Scan a workspace from a project root: cd repo && mdview . — file tree, click around, no GUI navigation.
• Render git diff for context-heavy review: git diff main...HEAD | mdview — get diff coloring as actual rendered markdown, not 4-space-indented terminal output.
• Pipe HTTP responses: curl https://example.com/spec.md | mdview — any URL that returns markdown becomes a temporary doc, no file written.
• Re-route an open file by piping a fresh copy: cat updated-spec.md | mdview — the active window swaps to the new content without you reopening the file dialog.