diff --git a/README.md b/README.md
index eb59ce5..56208cd 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,10 @@
 
 This repository is for deploying general purpose system software that is used on HPC targets, in this case gadi@NCI utilising the [build-cd](https://github.com/ACCESS-NRI/build-cd) infrastructure.
 
+## Versioning
+
+Versioning of tools in this repository consists of taking the official versions defined in the package, and appending a build number to the end of it (eg., for `yq 4.45.4`, the version would be `4.45.4-1`). This is so we are able to make changes unrelated to the package itself (eg. updating compilers and other lower-level dependenceis) without needing to wait and bundle changes until the next official release of a package we don't control. 
+
 ## Supported tools
 
 ### ncdu
@@ -30,6 +34,10 @@ The OpenSSH suite consists of the following tools:
 > pinentry system-tool was added primarily for [mosrs-auth simple password input dialog](https://github.com/ACCESS-NRI/dev-docs/wiki/MOSRS#mosrs-auth-with-a-simple-password-input-dialog).
 > For all other use cases, we recommend using Gadi's system pinentry, as ACCESS-NRI has not tested or validated this library configuration for security compliance.
 
+### yq
+
+[yq](https://mikefarah.gitbook.io/yq) is a lightweight YAML processor. 
+
 ## How to use
 
 **Requirements**: you must be a member of [`vk83`](https://my.nci.org.au/mancini/project/vk83).
diff --git a/yq/spack.yaml b/yq/spack.yaml
new file mode 100644
index 0000000..74dd722
--- /dev/null
+++ b/yq/spack.yaml
@@ -0,0 +1,38 @@
+# This is a Spack Environment file.
+#
+# It describes a set of packages to be installed, along with
+# configuration settings.
+#
+# This manifest is for installing yq, a command-line YAML processor.
+spack:
+  definitions:
+  # _name and _version are reserved definitions that inform build-cd deployments, and have no effect otherwise
+  - _name: [yq]
+  - _version: [4.45.4-1]
+  specs:
+  - yq@4.45.4
+  packages:
+    # Compilers
+    c:
+      require:
+      - 'gcc@15.1.0'
+    cxx:
+      require:
+      - 'gcc@15.1.0'
+    fortran:
+      require:
+      - 'gcc@15.1.0'
+    all:
+      prefer:
+      - 'target=x86_64_v3'
+  view: true
+  concretizer:
+    unify: true
+  modules:
+    default:
+      tcl:
+        include:
+        - yq
+        projections:
+          # build-cd will inject the _version into this projection
+          yq: 'system-tools/{name}'