diff --git a/codegen/README-models.md b/codegen/README-models.md
index ef70b1f..3afcc80 100644
--- a/codegen/README-models.md
+++ b/codegen/README-models.md
@@ -7,19 +7,18 @@ as they do in other languages. We can combine all models from AWS into a single
 comptime constant even, however, we're keeping zig files 1:1 with json files
 for now.
 
-The main executable, run with a "-s" first argument, will simply parse the
-Smithy json files passed by the rest of the arguments and save each one as
-its own file.json.zig. We will rely on shell commands to do the rest of the
-renaming (and moving if necessary).
+Optimization plan will be done by the placing of a json file in the output
+directory. The json file will contain a mapping between input files and generated
+outputs, as well as a top level directory hash. We can skip the output generation
+entirely if the top level hash matches, otherwise, individual hashes will be
+compared and output files will only regenerate if the input or output has changed.
 
-To run this, we can use `codegen -s models/*.json`, which takes 20 seconds
-or so on my i5 chromebook and probably significantly faster on a real machine.
-No attempt has been made to optimize. Also, there are several bugs:
+
+Todo
+----
 
 * I do not think all the optional types have been sorted.
 * I think there is necessary metadata missing from EC2Query style services
-* The output will compile and is close to what `zig fmt` likes to see, but it
-  has not yet been functionally tested
 * It handles all the types in existing AWS services, but it does not handle
   all known Smithy types (e.g. blob and document are missing)
 * It would be awesome to bring over the documentation from the model into
@@ -29,13 +28,7 @@ No attempt has been made to optimize. Also, there are several bugs:
   realistically I'm not sure if that will matter long term, and it's a fair
   amount of work as everything now can be done in a single pass without post
   processing.
-* This doesn't seem to build on 0.7.1 - you need master branch. I hope that
-  0.8.0 will be out soon. If not, a few syntax changes need to be accommodated.
-
-Some of these will likely be addressed as I integrate the code generated files into
-the SDK engine.
 
 The models are Smithy json files, sourced from the AWS v2 go sdk
-for lack of a better place. I've just downloaded the main branch and copied
-the files from the tree in place.
-
+for lack of a better place. Details are in build.zig of the parent project
+that is now responsible for downloading/caching the project.