diff --git a/src/Abstractions/Compendium.Abstractions.Git/Webhooks/IGitWebhookIngestor.cs b/src/Abstractions/Compendium.Abstractions.Git/Webhooks/IGitWebhookIngestor.cs
index 35ee182..7de1684 100644
--- a/src/Abstractions/Compendium.Abstractions.Git/Webhooks/IGitWebhookIngestor.cs
+++ b/src/Abstractions/Compendium.Abstractions.Git/Webhooks/IGitWebhookIngestor.cs
@@ -85,11 +85,16 @@ public sealed record TagPushed(string Tag, string CommitSha) : GitWebhookEvent;
     /// <param name="Number">The pull request number.</param>
     /// <param name="SourceReference">The source branch.</param>
     /// <param name="TargetReference">The target branch.</param>
+    /// <param name="SourceHeadSha">
+    /// The head commit SHA of the source branch, when the provider reports it —
+    /// CI/CD consumers need it to build or deploy the exact proposed revision.
+    /// </param>
     public sealed record PullRequestChanged(
         string Action,
         int Number,
         string SourceReference,
-        string TargetReference) : GitWebhookEvent;
+        string TargetReference,
+        string? SourceHeadSha = null) : GitWebhookEvent;
 
     /// <summary>
     /// A pipeline run reached a terminal state.
diff --git a/src/Adapters/Compendium.Adapters.GitHub/Webhooks/GitHubWebhookIngestor.cs b/src/Adapters/Compendium.Adapters.GitHub/Webhooks/GitHubWebhookIngestor.cs
index 2f276d1..af95ba3 100644
--- a/src/Adapters/Compendium.Adapters.GitHub/Webhooks/GitHubWebhookIngestor.cs
+++ b/src/Adapters/Compendium.Adapters.GitHub/Webhooks/GitHubWebhookIngestor.cs
@@ -101,10 +101,12 @@ private static GitWebhookEvent TranslatePullRequest(JsonElement root, string del
         var pr = GetProperty(root, "pull_request");
         var action = GetString(root, "action") ?? string.Empty;
         var number = GetInt(root, "number") ?? GetInt(pr, "number") ?? 0;
-        var source = GetString(GetProperty(pr, "head"), "ref") ?? string.Empty;
+        var head = GetProperty(pr, "head");
+        var source = GetString(head, "ref") ?? string.Empty;
         var targetRef = GetString(GetProperty(pr, "base"), "ref") ?? string.Empty;
+        var headSha = GetString(head, "sha");
 
-        return new GitWebhookEvent.PullRequestChanged(action, number, source, targetRef)
+        return new GitWebhookEvent.PullRequestChanged(action, number, source, targetRef, headSha)
         {
             DeliveryId = deliveryId,
             Repository = repository,
diff --git a/tests/Unit/Compendium.Adapters.GitHub.Tests/GitHubWebhookIngestorTests.cs b/tests/Unit/Compendium.Adapters.GitHub.Tests/GitHubWebhookIngestorTests.cs
index 7e4975c..a957f88 100644
--- a/tests/Unit/Compendium.Adapters.GitHub.Tests/GitHubWebhookIngestorTests.cs
+++ b/tests/Unit/Compendium.Adapters.GitHub.Tests/GitHubWebhookIngestorTests.cs
@@ -95,7 +95,7 @@ public void Parse_TagPush_ProducesATagPushedEvent()
     public void Parse_PullRequest_ProducesAPullRequestChangedEvent()
     {
         var body = """
-        {"action":"opened","number":42,"pull_request":{"head":{"ref":"feature"},"base":{"ref":"main"}},
+        {"action":"opened","number":42,"pull_request":{"head":{"ref":"feature","sha":"headsha42"},"base":{"ref":"main"}},
          "repository":{"full_name":"acme/billing"}}
         """;
 
@@ -106,6 +106,21 @@ public void Parse_PullRequest_ProducesAPullRequestChangedEvent()
         pr.Number.Should().Be(42);
         pr.SourceReference.Should().Be("feature");
         pr.TargetReference.Should().Be("main");
+        pr.SourceHeadSha.Should().Be("headsha42");
+    }
+
+    [Fact]
+    public void Parse_PullRequestWithoutHeadSha_LeavesSourceHeadShaNull()
+    {
+        var body = """
+        {"action":"opened","number":7,"pull_request":{"head":{"ref":"feature"},"base":{"ref":"main"}},
+         "repository":{"full_name":"acme/billing"}}
+        """;
+
+        var result = _ingestor.Parse(Delivery("pull_request", body), Secret);
+
+        var pr = result.Value.Should().BeOfType<GitWebhookEvent.PullRequestChanged>().Subject;
+        pr.SourceHeadSha.Should().BeNull();
     }
 
     [Fact]