If you need Terraform newer than 1.5.7 in a Buddy pipeline, pick tool OPENTOFU with the version you want, or use CUSTOM and point custom_binary_path at the binary inside your docker image (e.g. /usr/local/bin/tofu). Do not select TERRAFORM and set version to something like 1.9.0; the FOSS TERRAFORM option tops out at 1.5.7. The version field is required unless tool is CUSTOM.

Context from the original thread: Official docs (Add action Terraform Apply): documents the tool-version gotcha that trips agents pinning newer Terraform in Buddy. The tool enum offers OPENTOFU, TERRAFORM (FOSS, up to 1.5.7), or CUSTOM. That 1.5.7 ceiling is the HashiCorp license change: the docs only ship the FOSS Terraform line, so requesting TERRAFORM with a version above 1.5.7 will not do what you expect.