diff --git a/actions/changeset/check-coverage/action.yaml b/actions/changeset/check-coverage/action.yaml
index 07f97209..8bf83617 100644
--- a/actions/changeset/check-coverage/action.yaml
+++ b/actions/changeset/check-coverage/action.yaml
@@ -7,7 +7,8 @@ description: |
     - editing files inside a workspace package (e.g. block code under
       packages/<pkg>/) without adding that package to the changeset;
     - bumping a catalog version in pnpm-workspace.yaml without a matching
-      bump for the workflow packages that consume it via `catalog:`.
+      bump for packages that consume it as a runtime dependency via
+      `catalog:` — build-tool bumps in devDependencies are ignored.
 
   Runs after `pnpm install`. Requires the runner to have `pnpm`, `jq`, and
   `yq` (mikefarah, v4+) on PATH — all pre-installed on GitHub-hosted
diff --git a/actions/changeset/check-coverage/check-coverage.sh b/actions/changeset/check-coverage/check-coverage.sh
index a7ad8311..4fc6d08e 100755
--- a/actions/changeset/check-coverage/check-coverage.sh
+++ b/actions/changeset/check-coverage/check-coverage.sh
@@ -10,9 +10,17 @@
 #      git-diff check itself.
 #
 #   2. Catalog version bumps in pnpm-workspace.yaml: for each touched
-#      catalog key, find workspace packages that consume it via
+#      catalog key, find workspace packages that consume it as a runtime
+#      dependency (`dependencies` or `peerDependencies`) via
 #      `"<key>": "catalog:..."` and require those packages to bump.
 #
+#      Runtime sections only — skip devDependencies and optionalDependencies.
+#      A build-tool bump (e.g. @platforma-sdk/block-tools in a block's model,
+#      @platforma-sdk/tengo-builder in its workflow) leaves the published
+#      artifact unchanged, and `pnpm changeset` ignores it too. Counting it
+#      flagged packages the PR never touched — e.g. a UI-only change that
+#      carried a shared build-tool bump.
+#
 # Skips private (unpublished) workspace packages — they never appear in
 # the changeset's release set.
 #
@@ -186,8 +194,10 @@ if git diff --name-only "origin/${BASE_BRANCH}...HEAD" | grep -qx 'pnpm-workspac
         [ "${pkg_is_private[${name}]:-false}" = 'true' ] && continue
         pj="${pkg_name_to_dir[${name}]}/package.json"
         [ -f "${pj}" ] || continue
+        # Runtime sections only — a build-tool bump in devDependencies leaves
+        # the published artifact unchanged (see the header note).
         if jq -e --arg k "${key}" '
-            [.dependencies?, .devDependencies?, .peerDependencies?, .optionalDependencies?]
+            [.dependencies?, .peerDependencies?]
             | map(select(. != null) | to_entries) | add // []
             | map(select(.key == $k and ((.value // "") | startswith("catalog:"))))
             | length > 0
diff --git a/actions/changeset/check-coverage/test/coverage.bats b/actions/changeset/check-coverage/test/coverage.bats
index 369a6d98..8c891049 100644
--- a/actions/changeset/check-coverage/test/coverage.bats
+++ b/actions/changeset/check-coverage/test/coverage.bats
@@ -116,6 +116,19 @@ setup() {
   [ "${status}" -eq 0 ]
 }
 
+@test "catalog bump consumed only as a devDependency does not flag the consumer" {
+  # is-string is a runtime dep of pkg-c but only a devDependency of pkg-dev.
+  # Bumping it flags pkg-c and leaves pkg-dev alone — the block case where a
+  # build-tool catalog dep (block-tools, tengo-builder) bumps while the
+  # package stays untouched. Runtime-only scoping fixed this; pkg-dev was
+  # flagged before.
+  bump_catalog 'is-string' '^1.0.8'
+  run_check
+  [ "${status}" -eq 1 ]
+  [[ "${output}" == *'@check-coverage-test/pkg-c'* ]]
+  [[ "${output}" != *'@check-coverage-test/pkg-dev'* ]]
+}
+
 # ---------------------------------------------------------------------------
 # Empty-changeset corner case.
 # ---------------------------------------------------------------------------
diff --git a/actions/changeset/check-coverage/test/fixtures/minimal-workspace/packages/pkg-dev/index.js b/actions/changeset/check-coverage/test/fixtures/minimal-workspace/packages/pkg-dev/index.js
new file mode 100644
index 00000000..08200410
--- /dev/null
+++ b/actions/changeset/check-coverage/test/fixtures/minimal-workspace/packages/pkg-dev/index.js
@@ -0,0 +1,3 @@
+// Consumes is-string only as a devDependency (a build-tool stand-in), so a
+// catalog bump for is-string leaves this package out of the required set.
+module.exports = {};
diff --git a/actions/changeset/check-coverage/test/fixtures/minimal-workspace/packages/pkg-dev/package.json b/actions/changeset/check-coverage/test/fixtures/minimal-workspace/packages/pkg-dev/package.json
new file mode 100644
index 00000000..ab988896
--- /dev/null
+++ b/actions/changeset/check-coverage/test/fixtures/minimal-workspace/packages/pkg-dev/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "@check-coverage-test/pkg-dev",
+  "version": "1.0.0",
+  "main": "index.js",
+  "devDependencies": {
+    "is-string": "catalog:"
+  }
+}