diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 99d5f021..ed3c7e3e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -9,7 +9,8 @@ If you want to build Corepack yourself, you can build the project like this:
 
 The `dist/` directory now contains the corepack build and the shims.
 Call `node ./dist/corepack --help` and behold.
-You can also run the tests with `yarn test`.
+
+You can also run the tests with `yarn test`. (Do not set the environment variable `DEBUG=corepack` when running tests. The additional debug logging causes tests to fail.)
 
 # Adding a new package manager
 
diff --git a/README.md b/README.md
index d94614af..ec199375 100644
--- a/README.md
+++ b/README.md
@@ -312,6 +312,8 @@ There are a wide variety of networking issues that can occur while running
   `curl [URL]` (ipv4) and `curl -6 [URL]` (ipv6) from your shell.
 - Check your proxy settings (see [Environment Variables](#environment-variables)).
 
+The environment variable `DEBUG` can be set to `corepack` to enable additional debug logging.
+
 ## Contributing
 
 See [`CONTRIBUTING.md`](./CONTRIBUTING.md).