diff --git a/src/ClaudeDo.Releases/SelfUpdateResult.cs b/src/ClaudeDo.Releases/SelfUpdateResult.cs
index 82acdca..6d2f96e 100644
--- a/src/ClaudeDo.Releases/SelfUpdateResult.cs
+++ b/src/ClaudeDo.Releases/SelfUpdateResult.cs
@@ -1,3 +1,15 @@
 namespace ClaudeDo.Releases;
 
 public sealed record InstallerAssetMatch(ReleaseAsset Asset, string Version);
+
+public enum SelfUpdateDecisionKind
+{
+    NoUpdate,
+    UpdateAvailable,
+}
+
+public sealed record SelfUpdateDecision(
+    SelfUpdateDecisionKind Kind,
+    string? LatestVersion = null,
+    ReleaseAsset? InstallerAsset = null,
+    ReleaseAsset? ChecksumsAsset = null);
diff --git a/src/ClaudeDo.Releases/SelfUpdater.cs b/src/ClaudeDo.Releases/SelfUpdater.cs
index b5df89d..71d18f2 100644
--- a/src/ClaudeDo.Releases/SelfUpdater.cs
+++ b/src/ClaudeDo.Releases/SelfUpdater.cs
@@ -1,3 +1,4 @@
+using System.Net.Http;
 using System.Text.RegularExpressions;
 
 namespace ClaudeDo.Releases;
@@ -19,4 +20,40 @@ public static partial class SelfUpdater
         }
         return null;
     }
+
+    public static async Task<SelfUpdateDecision> DecideUpdateAsync(
+        IReleaseClient releases,
+        string currentVersion,
+        CancellationToken ct)
+    {
+        GiteaRelease? release;
+        try
+        {
+            release = await releases.GetLatestReleaseAsync(ct);
+        }
+        catch (Exception ex) when (ex is HttpRequestException or TaskCanceledException)
+        {
+            return new SelfUpdateDecision(SelfUpdateDecisionKind.NoUpdate);
+        }
+
+        if (release is null)
+            return new SelfUpdateDecision(SelfUpdateDecisionKind.NoUpdate);
+
+        var match = FindInstallerAsset(release.Assets);
+        if (match is null)
+            return new SelfUpdateDecision(SelfUpdateDecisionKind.NoUpdate);
+
+        var cmp = VersionComparer.Compare(match.Version, currentVersion);
+        if (!cmp.IsNewer)
+            return new SelfUpdateDecision(SelfUpdateDecisionKind.NoUpdate);
+
+        var checksums = release.Assets.FirstOrDefault(
+            a => string.Equals(a.Name, "checksums.txt", StringComparison.OrdinalIgnoreCase));
+
+        return new SelfUpdateDecision(
+            SelfUpdateDecisionKind.UpdateAvailable,
+            LatestVersion: match.Version,
+            InstallerAsset: match.Asset,
+            ChecksumsAsset: checksums);
+    }
 }
diff --git a/tests/ClaudeDo.Releases.Tests/SelfUpdaterTests.cs b/tests/ClaudeDo.Releases.Tests/SelfUpdaterTests.cs
index 9abaf70..efb46de 100644
--- a/tests/ClaudeDo.Releases.Tests/SelfUpdaterTests.cs
+++ b/tests/ClaudeDo.Releases.Tests/SelfUpdaterTests.cs
@@ -1,3 +1,5 @@
+using System.Net.Http;
+
 namespace ClaudeDo.Releases.Tests;
 
 public class SelfUpdaterAssetMatchingTests
@@ -42,3 +44,83 @@ public class SelfUpdaterAssetMatchingTests
         Assert.Null(SelfUpdater.FindInstallerAsset(assets));
     }
 }
+
+public class SelfUpdaterDecisionTests
+{
+    private sealed class FakeReleaseClient : IReleaseClient
+    {
+        public GiteaRelease? Release { get; set; }
+        public bool Throw { get; set; }
+
+        public Task<GiteaRelease?> GetLatestReleaseAsync(CancellationToken ct)
+        {
+            if (Throw) throw new HttpRequestException("boom");
+            return Task.FromResult(Release);
+        }
+
+        public Task DownloadAsync(string url, string destPath, IProgress<long> progress, CancellationToken ct)
+            => throw new NotSupportedException("not used in decision tests");
+    }
+
+    [Fact]
+    public async Task Decide_NoRelease_NoUpdate()
+    {
+        var client = new FakeReleaseClient { Release = null };
+        var d = await SelfUpdater.DecideUpdateAsync(client, currentVersion: "0.1.0", CancellationToken.None);
+        Assert.Equal(SelfUpdateDecisionKind.NoUpdate, d.Kind);
+    }
+
+    [Fact]
+    public async Task Decide_NetworkError_NoUpdate()
+    {
+        var client = new FakeReleaseClient { Throw = true };
+        var d = await SelfUpdater.DecideUpdateAsync(client, "0.1.0", CancellationToken.None);
+        Assert.Equal(SelfUpdateDecisionKind.NoUpdate, d.Kind);
+    }
+
+    [Fact]
+    public async Task Decide_OlderLatest_NoUpdate()
+    {
+        var client = new FakeReleaseClient
+        {
+            Release = new GiteaRelease("v0.1.0", "rel", new[]
+            {
+                new ReleaseAsset("ClaudeDo.Installer-0.1.0.exe", "u", 1),
+            }),
+        };
+        var d = await SelfUpdater.DecideUpdateAsync(client, "0.2.0", CancellationToken.None);
+        Assert.Equal(SelfUpdateDecisionKind.NoUpdate, d.Kind);
+    }
+
+    [Fact]
+    public async Task Decide_NewerLatestWithAsset_UpdateAvailable()
+    {
+        var client = new FakeReleaseClient
+        {
+            Release = new GiteaRelease("v0.3.0", "rel", new[]
+            {
+                new ReleaseAsset("ClaudeDo.Installer-0.3.0.exe", "https://x", 20),
+                new ReleaseAsset("checksums.txt", "https://checks", 1),
+            }),
+        };
+        var d = await SelfUpdater.DecideUpdateAsync(client, "0.2.0", CancellationToken.None);
+        Assert.Equal(SelfUpdateDecisionKind.UpdateAvailable, d.Kind);
+        Assert.Equal("0.3.0", d.LatestVersion);
+        Assert.NotNull(d.InstallerAsset);
+        Assert.NotNull(d.ChecksumsAsset);
+    }
+
+    [Fact]
+    public async Task Decide_NewerLatestButNoInstallerAsset_NoUpdate()
+    {
+        var client = new FakeReleaseClient
+        {
+            Release = new GiteaRelease("v0.3.0", "rel", new[]
+            {
+                new ReleaseAsset("ClaudeDo-0.3.0-win-x64.zip", "u", 20),
+            }),
+        };
+        var d = await SelfUpdater.DecideUpdateAsync(client, "0.2.0", CancellationToken.None);
+        Assert.Equal(SelfUpdateDecisionKind.NoUpdate, d.Kind);
+    }
+}