diff --git a/lib/builderator.js b/lib/builderator.js
index 0e81081..7b6bcff 100644
--- a/lib/builderator.js
+++ b/lib/builderator.js
@@ -1,3 +1,8 @@
+/*
+  Useful system level functions for use in build commands.  It's mostly things like
+  detecting if two files changed, doing globs on Windows and Unix, and various
+  file operations that you need.
+ */
 import fg from "fast-glob";
 import fs from "fs";
 import assert from "assert";
@@ -6,7 +11,12 @@ import Path from "path";
 import { execSync } from "child_process";
 
 /*
- Fixes some common problems with fast-glob on windows.
+ Fixes some common problems with `fast-glob` on windows.  I removes
+ leading "C:\" from paths and replaces all of the `\\` with `/`.
+
+ __BUG__: This obviously won't work if you're on a different drive than C:.
+
+ + `path string` -- The path/glob pattern to use.
  */
 export const glob = (path) => {
   if(process.platform === "win32") {
@@ -19,6 +29,17 @@ export const glob = (path) => {
   }
 }
 
+/*
+  Detects if two files have changed.  This is used to avoid
+  writing or working on files that don't need it, similar
+  to the Unix make utility.
+
+  ___FOOTGUN___: It uses the stat.mtimeMs which may or may not be
+  the most reliable way to detect differences.
+
+  + `source string` -- The source path.
+  + `target string` -- The target path.
+ */
 export const changed = (source, target) => {
   // we want the source to error if it doesn't exist
   const s_stat = fs.statSync(source);
@@ -28,7 +49,11 @@ export const changed = (source, target) => {
   return !t_stat || s_stat.mtimeMs > t_stat.mtimeMs;
 }
 
-/* Makes a directory recursively. */
+/*
+  Makes a directory recursively, kind of like `mkdir -p`.
+
+  + `dir string` -- The full path to the final directory to create.
+ */
 export const mkdir = (dir) => {
   if(!fs.existsSync(dir)) {
     log.debug(`making dir ${dir}`);
@@ -37,13 +62,8 @@ export const mkdir = (dir) => {
 }
 
 /*
- Given any path to a file, makes sure all its directories are in place.
-
- Example:
-
- ```javascript
- console.log("PRINT");
- ```
+ Given any path to a file, makes sure all its directories are in place.  This will
+ only the directory to the file, and then calls `mkdir` on it to create the path.
 
  - `param string` -- path to file
  */
@@ -52,7 +72,14 @@ export const mkdir_to = (target) => {
   mkdir(dirs.dir);
 }
 
-/* Convenience function that makes sure the dir is there then writes the data. */
+/*
+  Convenience function that makes sure the dir is there then writes the data.
+  It's a combination of `mkdir_to` and `fs.writeFileSync` and exists because
+  these two operations are so common.
+
+  + `target string` -- Path to the file to write.
+  + `data string|buffer|etc.` -- Anything that `fs.writeFileSync` can take as file contents.
+ */
 export const write = (target, data) => {
   mkdir_to(target);
   fs.writeFileSync(target, data);
@@ -61,7 +88,12 @@ export const write = (target, data) => {
 /*
  Like write but does an OS copy after making the target dir. When given a
  filter it will give the filter function the arguments, let it return contents,
- then write those instead of a copy.
+ then write those instead of a copy.  This will create the target file's path
+ with `mkdir_to`.
+
+ + `src string` -- Source file path.
+ + `dest string` -- Destination path.
+ + `filter cb(src, dest, raw_data)` -- A function that can modify the data before it's written.
  */
 export const copy = (src, dest, filter=null) => {
   mkdir_to(dest);
@@ -70,7 +102,8 @@ export const copy = (src, dest, filter=null) => {
     try {
       let raw_data = fs.readFileSync(src);
       let data = filter(src, dest, raw_data);
-      write(dest, data);
+
+      fs.writeFileSync(dest, data);
     } catch (error) {
       log.error(error, "Problem with filter write in copy");
     }
@@ -79,6 +112,12 @@ export const copy = (src, dest, filter=null) => {
   }
 }
 
+/*
+  Removes a file, optionally ignoring any errors.
+
+  + `file_name string` -- The path to the file to remove.
+  + `ignore boolean (false)` -- Whether to ignore errors removing the file.
+ */
 export const rm = (file_name, ignore=false) => {
   log.warn("Deleting file", file_name);
   try {
@@ -93,27 +132,35 @@ export const rm = (file_name, ignore=false) => {
   }
 }
 
-export const index_rollup = (src_index, target_index, contents, key) => {
-  let index = JSON.parse(fs.readFileSync(src_index));
-
-  index[key] = glob(contents).map(f => JSON.parse(fs.readFileSync(f)));
-  assert(index[key] !== undefined, `Attempt to load contents into ${key} for ${src_index} failed with undefined.`);
-
-  write(target_index, JSON.stringify(index));
-
-  return index;
-}
+/*
+  Executes a command, and mostly just logs the command then run
+  execSync with the same options.
 
+  + `cmd string` -- Command to run.
+  + `opts Object` -- Options for `execSync`.
+ */
 export const exec = (cmd, opts) => {
   log.info(`EXEC ${cmd}`);
   return execSync(cmd, opts);
 }
 
+/*
+  Similar to `exec` but it is _interactive_ because it reroutes this process's stderr,
+  stdout, and stdin to the process.  If you find you can't ctrl-c then use this. The
+  options set are:
+
+  ```
+  {stdio: [process.stdout, process.stderr, process.stdin]}
+  ```
+
+  + `cmd string` -- The command to run.
+  + `opts Object` -- Additional options to set for the exec command.
+ */
 export const exec_i = (cmd, opts={}) => {
   return exec(cmd, {stdio: [process.stdout, process.stderr, process.stdin], ...opts});
 }
 
 
 export default {
-  index_rollup, rm, exec, changed, mkdir, mkdir_to, write, copy, exec_i, glob
+  rm, exec, changed, mkdir, mkdir_to, write, copy, exec_i, glob
 }