diff --git a/renovate.json b/renovate.json
index f20034a..3eaaa78 100644
--- a/renovate.json
+++ b/renovate.json
@@ -26,9 +26,9 @@
       "dependencyDashboardApproval": true
     },
     {
-      "description": "serde_json never automerges. Its publisher is trusted in supply-chain/audits.toml, so cargo vet passes its new releases with no per-version review, and the serde_core it resolves is a runtime dependency. A human merges every serde_json update.",
+      "description": "Cargo dev-dependency updates never automerge in this repo. This overrides the shared preset, which automerges them through its rust-dev-deps group and its dev-dependency rule. Crates whose publisher is trusted in supply-chain/audits.toml pass cargo vet with no per-version review, and any dev-dependency update can move a runtime dependency in the shared Cargo.lock. So the rule matches every dev-dependency, not only the trusted crates, and a human merges each one. Keep this rule last in this file: a later rule here that sets automerge would override it.",
       "matchManagers": ["cargo"],
-      "matchPackageNames": ["serde_json"],
+      "matchDepTypes": ["dev-dependencies"],
       "automerge": false
     }
   ]