diff --git a/.github/workflows/diff_shades.yml b/.github/workflows/diff_shades.yml
index 68cc2383306..464e5e9b92f 100644
--- a/.github/workflows/diff_shades.yml
+++ b/.github/workflows/diff_shades.yml
@@ -3,10 +3,10 @@ name: diff-shades
 on:
   push:
     branches: [main]
-    paths-ignore: ["docs/**", "tests/**", "**.md", "**.rst"]
+    paths: ["src/**", "setup.*", "pyproject.toml", ".github/workflows/*"]
 
   pull_request:
-    paths-ignore: ["docs/**", "tests/**", "**.md", "**.rst"]
+    paths: ["src/**", "setup.*", "pyproject.toml", ".github/workflows/*"]
 
   workflow_dispatch:
     inputs:
@@ -88,7 +88,8 @@ jobs:
         if: steps.baseline-cache.outputs.cache-hit != 'true'
         run: >
           diff-shades analyze -v --work-dir projects-cache/
-          ${{ steps.config.outputs.baseline-analysis }} -- ${{ github.event.inputs.baseline-args }}
+          ${{ steps.config.outputs.baseline-analysis }} --
+          ${{ steps.config.outputs.extra-args }} ${{ github.event.inputs.baseline-args }}
 
       - name: Build and install target revision
         env:
@@ -102,7 +103,8 @@ jobs:
         run: >
           diff-shades analyze -v --work-dir projects-cache/
           ${{ steps.config.outputs.target-analysis }} --repeat-projects-from
-          ${{ steps.config.outputs.baseline-analysis }} -- ${{ github.event.inputs.target-args }}
+          ${{ steps.config.outputs.baseline-analysis }} --
+          ${{ steps.config.outputs.extra-args }} ${{ github.event.inputs.target-args }}
 
       - name: Generate HTML diff report
         run: >
diff --git a/docs/contributing/gauging_changes.md b/docs/contributing/gauging_changes.md
index 59c40eb3909..786a1317342 100644
--- a/docs/contributing/gauging_changes.md
+++ b/docs/contributing/gauging_changes.md
@@ -34,6 +34,11 @@ these rules:
 | On PRs                | latest commit on `main` | PR commit with `main` merged |
 | On pushes (main only) | latest PyPI version     | the pushed commit            |
 
+```{note}
+Except for manually triggered runs, `preview=True` is forcefully set for all projects so
+we can gauge the impact ahead of time (which is literally the purpose of this workflow).
+```
+
 Once finished, a PR comment will be posted embedding a summary of the changes and links
 to further information. If there's a pre-existing diff-shades comment, it'll be updated
 instead the next time the workflow is triggered on the same PR.
diff --git a/scripts/diff_shades_gha_helper.py b/scripts/diff_shades_gha_helper.py
index f1f7f2be91c..d2df179dea3 100644
--- a/scripts/diff_shades_gha_helper.py
+++ b/scripts/diff_shades_gha_helper.py
@@ -185,6 +185,10 @@ def config(
     set_output("baseline-setup-cmd", baseline_cmd)
     set_output("target-analysis", target_name + ".json")
     set_output("target-setup-cmd", target_cmd)
+    # Except for manually triggered runs, it's more useful to force --preview for all
+    # projects so we can gauge the impact ahead of time (which is literally the purpose
+    # of this workflow).
+    set_output("extra-args", "" if event == "workflow_dispatch" else "--preview")
 
     key = f"{platform.system()}-{platform.python_version()}-{diff_shades.__version__}"
     key += f"-{baseline_name}-{baseline_args.encode('utf-8').hex()}"
diff --git a/src/black/__init__.py b/src/black/__init__.py
index 8c28b6ba18b..f58c7d7dfde 100644
--- a/src/black/__init__.py
+++ b/src/black/__init__.py
@@ -682,6 +682,9 @@ def reformat_code(
         report.failed(path, str(exc))
 
 
+# diff-shades depends on being to monkeypatch this function to operate. I know it's
+# not ideal, but this shouldn't cause any issues ... hopefully. ~ichard26
+@mypyc_attr(patchable=True)
 def reformat_one(
     src: Path, fast: bool, write_back: WriteBack, mode: Mode, report: "Report"
 ) -> None: