Describe Prep in README.md.

README.md

@@ -10,6 +10,30 @@
 
 </div>
 
+Prep is a cross-platform CLI tool that provides Rust workspace verification in single short command.
+You can just invoke `prep ci` and if the checks succeed then you can rest easy knowing that your PR won't fail CI.
+
+## Motivation
+
+Rust projects tend to have a wide variety of fairly complicated verification steps in CI.
+These steps help ensure that the project stays consistent and keeps working in various scenarios.
+
+However, these CI steps are either written as GitHub Action YAML files or as Bash scripts.
+Running GitHub Actions requires a rather heavyweight Docker image, which expects a Unix userland, just like Bash scripts.
+Additionally, they target ephemeral VMs, so they do a lot of tooling setup that isn't efficient for a local machine.
+All of that meaning that you're really out of luck on Windows and even on Unix it's going to be needlessly cumbersome.
+
+So you need to analyze the specifics of a project's CI and craft custom local scripts to emulate the CI steps.
+That, or you just manually invoke a few Cargo commands and hope for the best, leading to frequent CI failures on your PRs.
+Which sucks because CI tends to run at a lot slower speed than your local machine, especially due to cold build cache.
+
+## Prep to the rescue
+
+Before opening a PR you can just run `prep ci` locally and verify that everything matches CI expectations.
+Because Prep aims for a rather robust set of verifications this will be beneficial even when the project still uses custom CI scripts.
+However, for best results the project itself should run `prep ci` in its CI instead of custom scripts.
+That way the only problems that remain uncaught locally are platform specific, which the CI will catch with its multi-platform job matrix.
+
 ## Installation
 
 ```sh

prep/README.md

@@ -10,6 +10,30 @@
 
 </div>
 
+Prep is a cross-platform CLI tool that provides Rust workspace verification in single short command.
+You can just invoke `prep ci` and if the checks succeed then you can rest easy knowing that your PR won't fail CI.
+
+## Motivation
+
+Rust projects tend to have a wide variety of fairly complicated verification steps in CI.
+These steps help ensure that the project stays consistent and keeps working in various scenarios.
+
+However, these CI steps are either written as GitHub Action YAML files or as Bash scripts.
+Running GitHub Actions requires a rather heavyweight Docker image, which expects a Unix userland, just like Bash scripts.
+Additionally, they target ephemeral VMs, so they do a lot of tooling setup that isn't efficient for a local machine.
+All of that meaning that you're really out of luck on Windows and even on Unix it's going to be needlessly cumbersome.
+
+So you need to analyze the specifics of a project's CI and craft custom local scripts to emulate the CI steps.
+That, or you just manually invoke a few Cargo commands and hope for the best, leading to frequent CI failures on your PRs.
+Which sucks because CI tends to run at a lot slower speed than your local machine, especially due to cold build cache.
+
+## Prep to the rescue
+
+Before opening a PR you can just run `prep ci` locally and verify that everything matches CI expectations.
+Because Prep aims for a rather robust set of verifications this will be beneficial even when the project still uses custom CI scripts.
+However, for best results the project itself should run `prep ci` in its CI instead of custom scripts.
+That way the only problems that remain uncaught locally are platform specific, which the CI will catch with its multi-platform job matrix.
+
 ## Installation
 
 ```sh