diff --git a/.github/workflows/build_ruby.yml b/.github/workflows/build_ruby.yml
index ef26f63..ddb117b 100644
--- a/.github/workflows/build_ruby.yml
+++ b/.github/workflows/build_ruby.yml
@@ -47,7 +47,12 @@ jobs:
       - name: Output CHANGELOG
         run: cargo run --bin ruby_changelog -- --version "${{inputs.ruby_version}}"
       - name: Build Ruby
-        run: cargo run --bin ruby_build -- --version ${{inputs.ruby_version}} --base-image ${{matrix.base_image}} --arch ${{matrix.arch}}
+        run: cargo run --bin ruby_build -- --version ${{inputs.ruby_version}} --base-image ${{matrix.base_image}} --arch ${{matrix.arch}} --inventory "${{ matrix.base_image }}{{ matrix.arch }}-inventory.toml"
+      - name: Store inventory
+        id: store_inventory
+        run: |
+          echo "${{ matrix.base_image }}{{ matrix.arch }}=" > $GITHUB_OUTPUT
+          cat "${{ matrix.base_image }}{{ matrix.arch }}-inventory.toml  | jq -r . >> $GITHUB_OUTPUT"
       - name: Check Ruby
         run: cargo run --bin ruby_check -- --version ${{inputs.ruby_version}} --base-image ${{matrix.base_image}} --arch  ${{matrix.arch}} | tee $GITHUB_STEP_SUMMARY
       - name: Upload Ruby runtime archive to S3 dry run
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 37d07fd..7cd6aa9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -121,3 +121,31 @@ jobs:
           git diff --unified=0 remotes/origin/${{ github.base_ref }} ${{matrix.inventory}} | grep '^+' | grep -v '^+++' | cut -c2- > check_inventory.toml
       - name: Check manifest URLs
         run: cargo run --bin inventory_check -- check_inventory.toml
+
+  test-dependent-job:
+    runs-on: ubuntu-24.04
+    strategy:
+      matrix:
+        arch: ["amd64", "arm64"]
+        base_image: ["heroku-20", "heroku-22", "heroku-24"]
+    steps:
+      - name: Store inventory
+        id: store_inventory
+        run: |
+          echo "${{ matrix.base_image }}${{ matrix.arch }}=" > $GITHUB_OUTPUT
+          cat "${{ matrix.base_image }}${{ matrix.arch }}-inventory.toml  | jq -r . >> $GITHUB_OUTPUT"
+
+  after-test-dependent-job:
+    runs-on: ubuntu-24.04
+    needs: test-dependent-job
+    steps:
+      - name: Output GITHUB_OUTPUT
+        run: echo ${{needs.test-dependent-job.outputs}}
+      - name: Combine results
+        run: |
+          echo "Combining results..."
+          for key in $(jq -r 'keys[]' <<< "${{ toJson(needs.test-dependent-job.outputs) }}"); do
+            value=$(jq -r --arg key "$key" '.[$key]' <<< "${{ toJson(needs.test-dependent-job.outputs) }}")
+            echo "$value" >> combined.txt
+            echo "" >> combined.txt
+          done
diff --git a/ruby_executable/src/bin/ruby_build.rs b/ruby_executable/src/bin/ruby_build.rs
index 359e905..6134420 100644
--- a/ruby_executable/src/bin/ruby_build.rs
+++ b/ruby_executable/src/bin/ruby_build.rs
@@ -34,6 +34,9 @@ struct RubyArgs {
 
     #[arg(long = "base-image")]
     base_image: BaseImage,
+
+    #[arg(long = "inventory", default_value = "ruby_inventory.yml")]
+    inventory: PathBuf,
 }
 
 fn ruby_dockerfile_contents(base_image: &BaseImage) -> String {
@@ -62,10 +65,16 @@ fn ruby_build(args: &RubyArgs) -> Result<(), Box<dyn std::error::Error>> {
         arch,
         version,
         base_image,
+        inventory,
     } = args;
 
     let mut log = Print::new(std::io::stderr()).h1("Building Ruby");
-    let inventory = source_dir().join("ruby_inventory.toml");
+
+    let inventory = if inventory.is_absolute() {
+        inventory.clone()
+    } else {
+        source_dir().join(inventory)
+    };
     let volume_cache_dir = source_dir().join("cache");
     let volume_output_dir = source_dir().join("output");
 
diff --git a/shared/src/bin/inventory_update.rs b/shared/src/bin/inventory_update.rs
new file mode 100644
index 0000000..6758d4a
--- /dev/null
+++ b/shared/src/bin/inventory_update.rs
@@ -0,0 +1,5 @@
+//! A CLI to combine two inventory files on disk with
+
+// cargo run --bin inventory_update -- --update path/to/file --with path/to/other/file
+
+fn main() {}