diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index efaaeeb295..a585be5e75 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -8,5 +8,5 @@ Fixes #
 - [ ] `make format`
 - [ ] Changelog fragment in `changelog.d/`
 
-<!-- Required for any change to policy (programmes, parameters, eligibility, bug fixes). See .github/CONTRIBUTING.md ("Axiom parity"). Keep one standard option below, or use axiom: needed if you are an external contributor who cannot complete the Axiom work; a maintainer will follow up. -->
-axiom: <legal id> encoded-correct | <rulespec-uk PR> encoded | <rulespec-uk issue> queued | n/a: <reason>
+<!-- Required for any change to policy (programmes, parameters, eligibility, bug fixes). See .github/CONTRIBUTING.md ("Axiom parity"). Keep one option below (several claims can share the line, separated by `;`), or use axiom: needed if you are an external contributor who cannot complete the Axiom work; a maintainer will follow up. The Axiom parity check verifies the line and comments with suggestions; n/a categories are listed in PolicyEngine/.github CONTRIBUTING. -->
+axiom: <legal id> encoded-correct (<companion test>) | <rulespec-uk PR> encoded | <rulespec-uk issue> queued | n/a: <category>: <reason>
diff --git a/.github/workflows/axiom-parity.yaml b/.github/workflows/axiom-parity.yaml
new file mode 100644
index 0000000000..d3451f9435
--- /dev/null
+++ b/.github/workflows/axiom-parity.yaml
@@ -0,0 +1,21 @@
+# Checks the PR description's axiom: line (PolicyEngine/.github CONTRIBUTING,
+# "Mirror policy changes in Axiom") and suggests one. Warn-only for now: it
+# reports what would fail in the job summary and never blocks merging.
+name: Axiom parity
+
+on:
+  pull_request:
+    types: [opened, edited, synchronize, reopened, ready_for_review]
+
+permissions:
+  contents: read
+
+jobs:
+  axiom-parity:
+    uses: PolicyEngine/.github/.github/workflows/axiom-parity.yml@axiom-parity-check
+    with:
+      mode: warn
+      tooling-ref: axiom-parity-check
+    permissions:
+      contents: read
+      pull-requests: write
diff --git a/changelog.d/axiom-parity-check.changed.md b/changelog.d/axiom-parity-check.changed.md
new file mode 100644
index 0000000000..4ef2eed180
--- /dev/null
+++ b/changelog.d/axiom-parity-check.changed.md
@@ -0,0 +1 @@
+Run the Axiom parity check on pull requests (warn-only for now) and show the canonical axiom line in the PR template.