diff --git a/.github/workflows/pr-welcome.yaml b/.github/workflows/pr-welcome.yaml
new file mode 100644
index 0000000..e508c4a
--- /dev/null
+++ b/.github/workflows/pr-welcome.yaml
@@ -0,0 +1,64 @@
+# Explain the mirror contribution flow on every incoming pull request.
+#
+# This repository is a MIRROR. A PR opened here is landed on the canonical Gitea
+# repository and syncs back; because the merge preserves the contributor's
+# commits at their original SHAs, GitHub marks the PR "Merged" on its own as
+# soon as the mirror syncs -- with nobody visibly clicking Merge.
+#
+# Without this comment, that reads as a rejection: the contributor sees their PR
+# close with no review, no merge button pressed, and no explanation. It is
+# actually the successful outcome. Say so up front, before it happens.
+#
+# WHY pull_request_target AND NOT pull_request:
+# a `pull_request` run from a fork gets a read-only token, so it cannot post a
+# comment -- which is exactly the case this workflow exists to serve.
+# `pull_request_target` runs in the context of the BASE repo and gets a writable
+# token. That is only safe because this job never checks out or executes the
+# contributor's code; it posts a fixed string. Do not add a checkout of
+# `github.event.pull_request.head.sha` here -- that combination is the standard
+# pull_request_target privilege-escalation hole.
+name: Explain the mirror flow
+
+on:
+  pull_request_target:
+    types: [opened]
+
+permissions:
+  pull-requests: write
+
+jobs:
+  comment:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Post the contribution-flow explainer
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const body = [
+              "Thanks for this — and one thing worth knowing before it happens.",
+              "",
+              "**This repository is a mirror.** Development happens on Gitea at",
+              "`gitea.civilytics.org/Civilytics/uscogdata`. Your pull request will be fetched",
+              "from here, landed there, and synced back.",
+              "",
+              "Because that merge preserves your commits at their original SHAs, **GitHub will",
+              "mark this pull request \"Merged\" on its own** — without anyone visibly clicking",
+              "the Merge button, and possibly without a review comment on this page first.",
+              "",
+              "> If your pull request closes as \"Merged\" and nobody appears to have merged it,",
+              "> that is the normal, successful outcome — not a rejection.",
+              "",
+              "If it is *not* going to be merged, you will get an actual reply saying so.",
+              "",
+              "Substantial contributions get a `ctb` entry in `DESCRIPTION`, which surfaces in",
+              "`citation(\"uscogdata\")`. There is no CLA and no DCO sign-off.",
+              "",
+              "Full details: [CONTRIBUTING.md](https://github.com/civilytics/uscogdata/blob/main/CONTRIBUTING.md).",
+            ].join("\n");
+
+            await github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.payload.pull_request.number,
+              body,
+            });
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index f296d70..bb02716 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -101,5 +101,13 @@ but "usually" is not a release gate.
    variables set. This is the only check that catches a
    corpus-unreachable defect, and its absence is why 0.3.0 needed fixing.
 8. Bump `Version` and add a `NEWS.md` section.
-9. Tag, then update the r-universe registry pin at
-   `github.com/civilytics/civilytics.r-universe.dev`.
+9. Tag on **Gitea** (`git tag -a vX.Y.Z && git push origin vX.Y.Z`). The mirror
+   workflow carries tags to GitHub on its own — confirm the tag appears at
+   `github.com/civilytics/uscogdata/tags` before continuing.
+10. Update the r-universe registry pin at
+    `github.com/civilytics/civilytics.r-universe.dev` — edit `packages.json`'s
+    `branch` to the new tag. **r-universe will not pick up a release until this
+    is edited**: the pin is a tag, deliberately, so a mid-refactor `main` is
+    never published as a release. `"branch": "*release"` would track releases
+    automatically, but it needs a GitHub *Release* object and the mirror pushes
+    tags only — so it would silently never update.
diff --git a/README.md b/README.md
index a6ac34b..c265eb8 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,7 @@
 # uscogdata
 
 <!-- badges: start -->
+[![R-CMD-check](https://github.com/civilytics/uscogdata/actions/workflows/R-CMD-check.yaml/badge.svg)](https://github.com/civilytics/uscogdata/actions/workflows/R-CMD-check.yaml)
 [![r-universe](https://civilytics.r-universe.dev/badges/uscogdata)](https://civilytics.r-universe.dev/uscogdata)
 [![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE.md)
 <!-- badges: end -->