diff --git a/src/PostIt/PostIt.Tests/BlogApiTestFakes.cs b/src/PostIt/PostIt.Tests/BlogApiTestFakes.cs
index 4f102be20..112c11752 100644
--- a/src/PostIt/PostIt.Tests/BlogApiTestFakes.cs
+++ b/src/PostIt/PostIt.Tests/BlogApiTestFakes.cs
@@ -62,4 +62,17 @@ internal sealed class RecordingYavscApiClient : YavscApiClient
             });
         return Task.FromResult(default(T)!);
     }
+
+    /// <summary>Multipart overload: BlogApiClient routes
+    /// Create/UpdatePostAsync with attachments through here.
+    /// Without this override the call would fall through to the
+    /// base <see cref="YavscApiClient"/> and attempt a real HTTP
+    /// round-trip against the stub authority. The body is a
+    /// factory, so we record the delegate itself; tests that
+    /// care about the multipart shape invoke it.</summary>
+    public override Task<T> CallAsync<T>(HttpMethod method, string path, Func<HttpContent> contentFactory, CancellationToken ct = default)
+    {
+        _recorder.Calls.Add((method, path, contentFactory));
+        return Task.FromResult(default(T)!);
+    }
 }
diff --git a/src/PostIt/PostIt.Tests/BlogAttachmentLinkTests.cs b/src/PostIt/PostIt.Tests/BlogAttachmentLinkTests.cs
new file mode 100644
index 000000000..6572fdfbb
--- /dev/null
+++ b/src/PostIt/PostIt.Tests/BlogAttachmentLinkTests.cs
@@ -0,0 +1,75 @@
+using Yavsc.Blogspot;
+using Yavsc.Api.Client;
+using PostIt.ViewModels;
+
+namespace PostIt.Tests;
+
+/// <summary>
+/// Pins the markdown link that <see cref="BlogsViewModel.SaveAsync"/>
+/// appends to the article after a successful attachment upload.
+///
+/// <para>The link must be an absolute URL derived from the OIDC
+/// authority via <c>FileServerUrlHelpers.GetUserFilesUri</c>
+/// (Yavsc.Abstract): the <c>/files</c> file server is hosted by
+/// Yavsc.Org — the IdP — not by the blogs API host, so a link
+/// built from <c>BlogsApiUrl</c> (or left relative) 404s when the
+/// reader opens the post. The regression this guards: a generated
+/// link of the shape <c>/files/{user}/blogs/{id}/{name}</c>
+/// (relative, authority-less) instead of
+/// <c>https://{authority}/files/{user}/blogs/{id}/{name}</c>.</para>
+/// </summary>
+public class BlogAttachmentLinkTests
+{
+    [Fact]
+    public async Task Save_with_attachment_appends_absolute_link_derived_from_the_oidc_authority()
+    {
+        const string authority = "https://idp.example.test";
+
+        var recorder = new CallRecorder();
+        var api = new RecordingYavscApiClient(recorder);
+        var blog = new BlogApiClient(api, "https://blogs.example.test/api/v1/");
+        var settings = new Settings
+        {
+            Authentication = new AuthenticationSettings
+            {
+                Authority = authority,
+                ClientId = "stub",
+                Scopes = new[] { "openid" },
+            },
+        };
+        var vm = new BlogsViewModel(blog, settings);
+
+        // Update branch: an existing post is selected, the user
+        // edits the buffers and attaches a file.
+        vm.SelectedPost = new BlogPostDto
+        {
+            Id = 42,
+            AuthorId = "tester",
+            Title = "Avant",
+            Article = "Contenu initial.",
+            DateCreated = DateTime.UtcNow,
+            DateModified = DateTime.UtcNow,
+        };
+        vm.DraftTitle = "Après";
+        vm.DraftArticle = "Contenu modifié.";
+        vm.DraftAttachments.Add(new BlogUploadFile(
+            "note.txt",
+            System.Text.Encoding.UTF8.GetBytes("payload test"),
+            "text/plain"));
+
+        await vm.SaveAsync();
+
+        // The update branch issues two PUTs: the multipart one
+        // carrying the file, then — because TryAppendAttachmentLinks
+        // appended a link — a JSON one carrying the final article.
+        var linkPut = recorder.Calls.LastOrDefault(
+            c => c.method == HttpMethod.Put && c.body is BlogPostDto);
+        Assert.NotEqual(default, linkPut);
+        var sent = Assert.IsType<BlogPostDto>(linkPut.body);
+
+        var expectedUrl = $"{authority}/files/tester/blogs/42/note.txt";
+        Assert.Contains($"- [note.txt]({expectedUrl})", sent.Article);
+        // The regression shape: a relative, authority-less link.
+        Assert.DoesNotContain("](/files/", sent.Article);
+    }
+}