diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3bdbb9a..64a53af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.4] - 2026-06-13
+
+### Fixed
+
+- `changelog_changeset` now includes `:id` and declares `unique_constraint(:id, name: "#{table}_pkey")` so Ecto.ConstraintError on audit PK during `*_and_log` (inside transaction) becomes a changeset error instead of raising. Closes OPS-4617.
+
 ## [1.0.3] - 2026-05-28
 
 ### Fixed
diff --git a/lib/ecto_trail/ecto_trail.ex b/lib/ecto_trail/ecto_trail.ex
index 74d7075..50aada6 100644
--- a/lib/ecto_trail/ecto_trail.ex
+++ b/lib/ecto_trail/ecto_trail.ex
@@ -53,7 +53,7 @@ defmodule EctoTrail do
   # Cache frequently accessed config to avoid repeated lookups
   @redacted_fields_config Application.compile_env(:ecto_trail, :redacted_fields, nil)
   @default_max_params 65_000
-  @changelog_fields [:actor_id, :resource, :resource_id, :changeset, :change_type]
+  @changelog_fields [:id, :actor_id, :resource, :resource_id, :changeset, :change_type]
   @not_loaded_pattern "Ecto.Association.NotLoaded"
 
   defmacro __using__(_) do
@@ -573,5 +573,11 @@ defmodule EctoTrail do
 
   defp changelog_changeset(attrs) do
     Changeset.cast(%Changelog{}, attrs, @changelog_fields)
+    |> Changeset.unique_constraint(:id, name: pkey_constraint_name())
+  end
+
+  defp pkey_constraint_name do
+    table = Application.get_env(:ecto_trail, :table_name, "audit_log")
+    "#{table}_pkey"
   end
 end
diff --git a/mix.exs b/mix.exs
index c895a54..e08c811 100644
--- a/mix.exs
+++ b/mix.exs
@@ -1,7 +1,7 @@
 defmodule EctoTrail.Mixfile do
   use Mix.Project
 
-  @version "1.0.3"
+  @version "1.0.4"
 
   def project do
     [
diff --git a/test/unit/ecto_trail_test.exs b/test/unit/ecto_trail_test.exs
index 1a44768..ed13239 100644
--- a/test/unit/ecto_trail_test.exs
+++ b/test/unit/ecto_trail_test.exs
@@ -329,4 +329,44 @@ defmodule EctoTrailTest do
                )
     end
   end
+
+  describe "handles pkey constraint violations on audit_log gracefully (no ConstraintError)" do
+    test "insert_and_log succeeds even if audit PK would collide (e.g. sequence skew)" do
+      # Prime the audit_log with an explicit high id via insert_all (bypasses our changeset)
+      colliding_id = 1_000_007
+
+      # Insert a "dummy" changelog row claiming that id
+      {1, _} =
+        TestRepo.insert_all(
+          Changelog,
+          [
+            %{
+              id: colliding_id,
+              actor_id: "seq-collision",
+              resource: "resources",
+              resource_id: "0",
+              changeset: %{},
+              change_type: :insert,
+              inserted_at: DateTime.utc_now() |> DateTime.truncate(:second)
+            }
+          ]
+        )
+
+      # Force the sequence so the next generated id (via default) will collide with the one we inserted.
+      # setval(seq, n, true) sets last_value to n; next nextval() returns n+1.
+      # So set to colliding_id-1 to make the next default-generated id == colliding_id.
+      Ecto.Adapters.SQL.query!(TestRepo, "SELECT setval('audit_log_id_seq', $1, true)", [colliding_id - 1])
+
+      # Now perform an insert_and_log; internally it will let PG generate the id for the audit row,
+      # which will collide. Without unique_constraint handling on the changeset this raises Ecto.ConstraintError.
+      assert {:ok, %Resource{name: "collide-test"}} =
+               TestRepo.insert_and_log(%Resource{name: "collide-test"}, "pkey-actor")
+
+      # The main resource was inserted
+      assert TestRepo.exists?(from(r in Resource, where: r.name == "collide-test"))
+
+      # The log step did not succeed in inserting an audit row (constraint violation was turned into error)
+      refute TestRepo.exists?(from(c in Changelog, where: c.actor_id == "pkey-actor"))
+    end
+  end
 end