diff --git a/.github/workflows/deps.yml b/.github/workflows/deps.yml
index 2c98a1a502..c2191bd454 100644
--- a/.github/workflows/deps.yml
+++ b/.github/workflows/deps.yml
@@ -16,9 +16,21 @@ on:
         description: only this case, for example discourse-bundler (optional)
         type: string
         default: ""
+      cli_artifact:
+        description: BoringCache artifact id of a candidate CLI to run instead of the pinned release; never recorded (optional)
+        type: string
+        default: ""
+      cli_jsonl:
+        description: keep BoringCache CLI JSONL in each job's results artifact; never recorded
+        type: boolean
+        default: false
 
 run-name: Dependency cache update step ${{ inputs.step }}${{ inputs.case && format(' {0}', inputs.case) || '' }}${{ inputs.mode == 'preflight' && ' (preflight)' || '' }}
 
+env:
+  CANDIDATE_CLI_ARTIFACT: ${{ inputs.cli_artifact }}
+  BORINGCACHE_OBSERVABILITY_JSONL_PATH: ${{ inputs.cli_jsonl && format('{0}/deps-results/boringcache.jsonl', github.workspace) || '' }}
+
 concurrency:
   group: cache-deps
   cancel-in-progress: false
@@ -133,7 +145,7 @@ jobs:
 
   publish:
     needs: [plan, seed, update, verify]
-    if: ${{ !cancelled() && needs.plan.result == 'success' && github.ref == 'refs/heads/main' && inputs.mode == 'run' }}
+    if: ${{ !cancelled() && needs.plan.result == 'success' && github.ref == 'refs/heads/main' && inputs.mode == 'run' && inputs.cli_artifact == '' && !inputs.cli_jsonl }}
     runs-on: ubuntu-24.04
     permissions:
       contents: write
diff --git a/deps/plan.toml b/deps/plan.toml
index e455111b66..97e925dcbb 100644
--- a/deps/plan.toml
+++ b/deps/plan.toml
@@ -47,3 +47,19 @@ steps = [["bab418487a463eede4c7d2f6415fe2eb966a3883", "bbb722e4322eba62306788b6d
 BUNDLE_PATH = "vendor/bundle"
 BUNDLE_DEPLOYMENT = "true"
 BUNDLE_WITHOUT = "development"
+
+[cases.mastodon-bundler]
+repo = "mastodon/mastodon"
+tool = "bundler"
+ruby = "4.0.7"
+lockfile = "Gemfile.lock"
+path = "upstream/vendor/bundle"
+apt = ["libpq-dev", "libicu-dev", "libidn-dev", "libyaml-dev"]
+install = "bundle install --jobs 4"
+check = "bundle check"
+steps = [["85cc1449181c774a226ae42ec19dca3a2f7cce26", "bcbf3651da6d2e9d9e7966e8e97fb59bbe7665e0"]]
+
+[cases.mastodon-bundler.env]
+BUNDLE_PATH = "vendor/bundle"
+BUNDLE_DEPLOYMENT = "true"
+BUNDLE_WITHOUT = "development"
diff --git a/scripts/install-boringcache.sh b/scripts/install-boringcache.sh
index d7fa0cafb4..41f353ddfa 100644
--- a/scripts/install-boringcache.sh
+++ b/scripts/install-boringcache.sh
@@ -14,4 +14,11 @@ cd "$dir"
 curl --fail --silent --show-error --location --retry 3 --remote-name-all "$base/SHA256SUMS" "$base/$asset"
 grep " $asset\$" SHA256SUMS | sha256sum --check
 install -m 0755 "$asset" "$dir/boringcache"
+if [ -n "${CANDIDATE_CLI_ARTIFACT:-}" ]; then
+  candidate="$RUNNER_TEMP/boringcache-candidate"
+  "$dir/boringcache" ci run --oidc-provider github-actions -- \
+    "$dir/boringcache" artifact pull "$CANDIDATE_CLI_ARTIFACT" "$candidate" --workspace boringcache/benchmarks
+  install -m 0755 "$candidate/$asset" "$dir/boringcache"
+  "$dir/boringcache" --version
+fi
 echo "$dir" >> "$GITHUB_PATH"