diff --git a/flake.nix b/flake.nix
index 08b7bda..16b6403 100644
--- a/flake.nix
+++ b/flake.nix
@@ -13,11 +13,16 @@
       let
         pkgs = import nixpkgs { inherit system; };
 
+        # Cosmetic version, derived from the commit. The published image is
+        # tagged from the git tag (TANGLED_REF_NAME) in CI, not this.
+        version = self.shortRev or self.dirtyShortRev or "dev";
+
+        # Where the repo lives, so atcr.io can show its README and source link.
+        repoURL = "https://tangled.org/byjp.me/deepsky";
+
         deepsky = pkgs.buildGoModule {
           pname = "deepsky";
-          # Cosmetic derivation label, derived from the commit. The published
-          # image is tagged from the git tag (TANGLED_REF_NAME) in CI, not this.
-          version = self.shortRev or self.dirtyShortRev or "dev";
+          inherit version;
           src = ./.;
 
           # Hash of the fetched Go module sources. Regenerate after changing
@@ -50,6 +55,16 @@
               "1965/tcp" = { };
             };
             Env = [ "SSL_CERT_FILE=${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt" ];
+            # atcr.io reads these on push: it fetches io.atcr.readme and shows
+            # the title/description/source/version on the image's page.
+            Labels = {
+              "org.opencontainers.image.title" = "DeepSky";
+              "org.opencontainers.image.description" = "A Gemini window onto Bluesky.";
+              "org.opencontainers.image.source" = repoURL;
+              "org.opencontainers.image.documentation" = repoURL;
+              "org.opencontainers.image.version" = version;
+              "io.atcr.readme" = "${repoURL}/raw/main/README.md";
+            };
           };
         };
       in