diff --git a/readme.md b/readme.md
new file mode 100644
index 0000000..cc174d3
--- /dev/null
+++ b/readme.md
@@ -0,0 +1,27 @@
+# msp430-asm
+
+A toy assembler for the TI MSP430, built with MicroCorruption in mind.
+
+# Usage
+```sh
+msp430-asm [-|-f|--file]
+```
+The frontend isn't very smart. It does no fancy arg parsing, no key interpretation or cursor manipulation or TUI goodness that everyone knows and loves.
+It does four things: Read. Evaluate. Print. Loop. Basic REPL. It doesn't even check whether you're running interactively or not.
+
+By default, the assembler operates in repl mode, and each line is treated in isolation. This is great for quickly looking up an instruction.
+
+To parse an entire file at once, and get useful context when there's a parse error, pipe it in through stdin with `-` as such:
+```sh
+cat valid.asm | msp430-asm -f
+```
+
+You can press Ctrl+D on Linux to emit an EOF over the terminal.
+
+# Motivations
+
+- Microcorruption's assembler sucks
+- I got tired of stringly-typed Python
+- I wanted to write a parser
+- I wanted to write Rust
+- I'm a fan of interactive programs