diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index fd92284c61..df53eaea32 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -52,16 +52,18 @@ jobs:
         id: configure
         shell: node {0}
         run: |
+          const fs = require('fs');
+
           const enableSelfHosted = ${{ inputs.self_hosted }};
+          const buildMatrix = JSON.parse(fs.readFileSync("${{ github.workspace }}/build-matrix.json"));
 
           // Use enableSelfHosted to decide what the build matrix below should
           // include.
-          const {hosted, selfHosted} = require("${{ github.workspace }}/.github/workflows/build-matrix.json");
+          const {hosted, selfHosted} = buildMatrix;
           const include = enableSelfHosted ? hosted.concat(selfHosted) : hosted;
           const os = include.map((config) => config.os);
 
           // Output JSON objects consumed by the build matrix below.
-          const fs = require('fs');
           fs.writeFileSync(process.env.GITHUB_OUTPUT,
               [
                 `INCLUDE=${ JSON.stringify(include) }`,
diff --git a/.github/workflows/build-matrix.json b/build-matrix.json
similarity index 100%
rename from .github/workflows/build-matrix.json
rename to build-matrix.json