diff --git a/.agents/ci-caching.md b/.agents/ci-caching.md
index 77b87467e..490bac2d2 100644
--- a/.agents/ci-caching.md
+++ b/.agents/ci-caching.md
@@ -259,10 +259,20 @@ Eviction is rarely needed in normal operation — `DEPS_REFRESH` handles weekly
 
 ## What the cache does **not** cover
 
-- The `free-disk-space` and `setup-build-disk` composite actions run on every job — these reclaim runner-state, not Docker layers, so BuildKit caches don't apply.
+- The `free-disk-space` and `setup-build-disk` composite actions run on every job — these reclaim runner-state, not Docker layers, so BuildKit caches don't apply. `test.yml` deliberately does **not** use `free-disk-space`: it runs no buildx step, and the multi-GB fixture downloads that once justified it left `make test` in the test-suite reorg.
 - Intermediate artifacts of `Build (PR)` are not pushed anywhere — PRs only build for verification.
 - Darwin builds (see below) — macOS runners have no Docker daemon, so the registry-backed BuildKit cache cannot apply.
 
+### The Linux Go workflows set `cache: false` on purpose
+
+`test.yml`, `lint.yml`, `tests-e2e.yml` and friends pass `cache: false` to `actions/setup-go@v5`, unlike the darwin jobs. This looks like an oversight and is not.
+
+Measured over the week to 2026-07-30, the `Set up Go` step has a **median of 11 seconds** on these runners. There is essentially nothing to win: the module download is not where the time goes. The expensive steps are compilation and test execution (`Test (with coverage gate)` at ~18.6min, `Test Backend E2E` at ~14.5min), and Go's build cache would have to survive across runners to touch those.
+
+Enabling it also has a real cost. GitHub caps Actions cache at **10 GB per repo and the repo already sits at that ceiling** (31 entries), so every `setup-go` entry written by a branch with a distinct `go.sum` (222-375 MB on Linux, up to 1.4 GB on macOS) evicts something else. See the darwin cache budget below.
+
+Before re-enabling this, measure `Set up Go` again and confirm it has actually become slow. If room is needed in the 10 GB budget, the cheapest evictions are the `docker.io--tonistiigi--binfmt` entries (~30 MB each, trivially re-fetched).
+
 ## Darwin native caches
 
 `backend_build_darwin.yml` runs natively on `macOS-14` GitHub-hosted runners — there is no Docker, no BuildKit, no cross-job registry cache. Instead, the reusable workflow uses `actions/cache@v4` for four native caches that mirror the spirit of the Linux cache (warm by default, weekly refresh for unpinned Python deps, PRs read-only).
diff --git a/.github/workflows/build-test.yaml b/.github/workflows/build-test.yaml
index 23d61d0f5..34b41e09f 100644
--- a/.github/workflows/build-test.yaml
+++ b/.github/workflows/build-test.yaml
@@ -35,9 +35,15 @@ jobs:
         uses: actions/setup-go@v5
         with:
           go-version: 1.25
+      # A PR builds only the host target. The three-platform cross-compile
+      # (linux/amd64, linux/arm64, darwin/arm64) is the bulk of this job's
+      # ~6.6min median and no PR consumes the resulting binaries. The
+      # before-hooks (protogen-go, react-ui, go mod tidy) run either way, so the
+      # "is the release build broken" signal is unchanged. master and tags still
+      # build everything.
       - name: Run GoReleaser
         run: |
-          make dev-dist
+          make ${{ github.event_name == 'pull_request' && 'dev-dist-single' || 'dev-dist' }}
   launcher-build-darwin:
     runs-on: macos-latest
     steps:
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 7e702a7dd..7081d630c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -24,8 +24,13 @@ jobs:
         uses: actions/checkout@v7
         with:
           submodules: true
-      - name: Free disk space
-        uses: ./.github/actions/free-disk-space
+      # No free-disk-space step here on purpose. That action exists to make room
+      # for docker buildx layers, and this job runs no buildx step. It was also
+      # sized for a `make test` that downloaded multi-GB GGUF/whisper fixtures
+      # and built llama-cpp/whisper/stablediffusion-ggml; after the test-suite
+      # reorg it does neither (see the Makefile test target). It cost ~3min of
+      # every run, and its tool-cache:true wipe also forced setup-go and
+      # setup-node to re-download toolchains that ship preinstalled.
       - name: Setup Go ${{ matrix.go-version }}
         uses: actions/setup-go@v5
         with:
diff --git a/Makefile b/Makefile
index af40ee7cf..699c6fd61 100644
--- a/Makefile
+++ b/Makefile
@@ -172,6 +172,15 @@ build-dev: ## Run LocalAI in dev mode with live reload
 dev-dist:
 	$(GORELEASER) build --snapshot --clean
 
+## PR-time variant of dev-dist: builds only the host platform instead of all
+## three release targets (linux/amd64, linux/arm64, darwin/arm64). The point of
+## running goreleaser on a PR is to catch a broken config or a broken
+## before-hook (protogen-go, react-ui, go mod tidy), and --single-target still
+## exercises every one of those. Nothing consumes a PR's cross-compiled
+## binaries. master pushes and tags still run the full dev-dist/dist.
+dev-dist-single:
+	$(GORELEASER) build --snapshot --clean --single-target
+
 dist:
 	$(GORELEASER) build --clean