From 69bd63f02dd159c0ad60e8dc0b94b07f70c75649 Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 15:27:04 -0800
Subject: [PATCH 01/14] fix merge issue

---
 conductor/tracks.md | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/conductor/tracks.md b/conductor/tracks.md
index 8e99eb01f..6ee7e7968 100644
--- a/conductor/tracks.md
+++ b/conductor/tracks.md
@@ -1,6 +1,4 @@
 # Tracks Registry
-<<<<<<< 176990-guards-for-pr
-=======
 
 ---
 
@@ -12,4 +10,3 @@
 - [~] **Track: Build a Merge Queue Dashboard**
 *Link: [./tracks/merge_queue_dashboard_20260205/](./tracks/merge_queue_dashboard_20260205/)*
 
->>>>>>> main

From 365b2a2df6f5f942a0e16a58e15e7626332fa017 Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:06:11 -0800
Subject: [PATCH 02/14] feat(model): Add buildNumber to PresubmitCheckState

Task: Update PresubmitCheckState Model
Summary: Added buildNumber to PresubmitCheckState and mapped it from the LUCI build in the BuildToPresubmitCheckState extension.
Files: app_dart/lib/src/model/common/presubmit_check_state.dart, app_dart/test/model/common/presubmit_check_state_test.dart
Why: To allow tracking of the LUCI build number throughout the presubmit check processing lifecycle.
---
 .../model/common/presubmit_check_state.dart   |  3 ++
 .../common/presubmit_check_state_test.dart    | 32 ++++++++++++++++++
 .../tracks/add_build_number_20260212/plan.md  | 33 +++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 app_dart/test/model/common/presubmit_check_state_test.dart
 create mode 100644 conductor/tracks/add_build_number_20260212/plan.md

diff --git a/app_dart/lib/src/model/common/presubmit_check_state.dart b/app_dart/lib/src/model/common/presubmit_check_state.dart
index a058e524d..13eeb2a50 100644
--- a/app_dart/lib/src/model/common/presubmit_check_state.dart
+++ b/app_dart/lib/src/model/common/presubmit_check_state.dart
@@ -19,6 +19,7 @@ class PresubmitCheckState {
   final int? startTime;
   final int? endTime;
   final String? summary;
+  final int? buildNumber;
 
   const PresubmitCheckState({
     required this.buildName,
@@ -27,6 +28,7 @@ class PresubmitCheckState {
     this.startTime,
     this.endTime,
     this.summary,
+    this.buildNumber,
   });
 }
 
@@ -38,5 +40,6 @@ extension BuildToPresubmitCheckState on bbv2.Build {
     startTime: startTime.toDateTime().microsecondsSinceEpoch,
     endTime: endTime.toDateTime().microsecondsSinceEpoch,
     summary: summaryMarkdown,
+    buildNumber: number,
   );
 }
diff --git a/app_dart/test/model/common/presubmit_check_state_test.dart b/app_dart/test/model/common/presubmit_check_state_test.dart
new file mode 100644
index 000000000..1519ff9b2
--- /dev/null
+++ b/app_dart/test/model/common/presubmit_check_state_test.dart
@@ -0,0 +1,32 @@
+// Copyright 2025 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:cocoon_service/src/model/common/presubmit_check_state.dart';
+import 'package:buildbucket/buildbucket_pb.dart' as bbv2;
+import 'package:cocoon_common/task_status.dart';
+import 'package:fixnum/fixnum.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('PresubmitCheckState', () {
+    test('BuildToPresubmitCheckState extension maps build number', () {
+      final build = bbv2.Build(
+        builder: bbv2.BuilderID(builder: 'linux_test'),
+        status: bbv2.Status.SUCCESS,
+        number: 12345,
+        startTime: bbv2.Timestamp(seconds: Int64(1000)),
+        endTime: bbv2.Timestamp(seconds: Int64(2000)),
+        summaryMarkdown: 'Summary',
+        tags: [
+          bbv2.StringPair(key: 'github_checkrun', value: '123'),
+        ],
+      );
+
+      final state = build.toPresubmitCheckState();
+      expect(state.buildName, 'linux_test');
+      expect(state.status, TaskStatus.succeeded);
+      expect(state.buildNumber, 12345);
+    });
+  });
+}
diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
new file mode 100644
index 000000000..28eee6892
--- /dev/null
+++ b/conductor/tracks/add_build_number_20260212/plan.md
@@ -0,0 +1,33 @@
+# Implementation Plan: Add `buildNumber` to `PresubmitCheck`
+
+This plan outlines the steps to add an optional `buildNumber` field across the Cocoon backend models and ensure it is populated during the check run completion process.
+
+## Phase 1: Model Updates
+
+This phase focuses on updating the internal and external data models to support the new `buildNumber` field.
+
+- [x] Task: Update `PresubmitCheckState` Model
+    - [ ] Add `int? buildNumber` to `PresubmitCheckState` class in `app_dart/lib/src/model/common/presubmit_check_state.dart`.
+    - [ ] Update `BuildToPresubmitCheckState` extension to map `number` from `bbv2.Build` to `buildNumber`.
+    - [ ] Update existing tests to reflect constructor changes.
+- [ ] Task: Update `PresubmitCheck` Firestore Model
+    - [ ] Add `fieldBuildNumber` constant and `buildNumber` getter/setter to `PresubmitCheck` in `app_dart/lib/src/model/firestore/presubmit_check.dart`.
+    - [ ] Update `fromDocument`, `init`, and `toJson` (or equivalent) to handle the new field.
+    - [ ] Add unit tests for serialization/deserialization of `buildNumber`.
+- [ ] Task: Update `PresubmitCheckResponse` RPC Model
+    - [ ] Add `int? buildNumber` to `PresubmitCheckResponse` in `packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart`.
+    - [ ] Run `dart run build_runner build --delete-conflicting-outputs` in `packages/cocoon_common/` to regenerate JSON serialization code.
+    - [ ] Add unit tests for the RPC model.
+- [ ] Task: Conductor - User Manual Verification 'Model Updates' (Protocol in workflow.md)
+
+## Phase 2: Backend Logic and API Updates
+
+This phase integrates the new field into the core logic and ensures it is returned by the API.
+
+- [ ] Task: Update `UnifiedCheckRun.markConclusion` Logic
+    - [ ] Update `markConclusion` in `app_dart/lib/src/service/firestore/unified_check_run.dart` to assign `state.buildNumber` to `presubmitCheck.buildNumber`.
+    - [ ] Add/update tests in `app_dart/test/service/firestore/unified_check_run_test.dart` to verify the build number is correctly saved to Firestore.
+- [ ] Task: Update `GetPresubmitChecks` API Handler
+    - [ ] Update `GetPresubmitChecks` in `app_dart/lib/src/request_handlers/get_presubmit_checks.dart` to map `PresubmitCheck.buildNumber` to `PresubmitCheckResponse.buildNumber`.
+    - [ ] Update handler tests to verify the API response contains the build number.
+- [ ] Task: Conductor - User Manual Verification 'Backend Logic and API Updates' (Protocol in workflow.md)

From 643f0440b6652191f80019ef814e1a208fb06efb Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:06:42 -0800
Subject: [PATCH 03/14] feat(model): Add buildNumber to PresubmitCheck
 Firestore Model

Task: Update PresubmitCheck Firestore Model
Summary: Added buildNumber setter and unit tests to the PresubmitCheck Firestore model.
Files: app_dart/lib/src/model/firestore/presubmit_check.dart, app_dart/test/model/firestore/presubmit_check_test.dart
Why: To enable storing and retrieving the LUCI build number in Firestore for each presubmit check attempt.
---
 .../lib/src/model/firestore/presubmit_check.dart   |  8 ++++++++
 .../test/model/firestore/presubmit_check_test.dart | 14 ++++++++++++++
 conductor/tracks/add_build_number_20260212/plan.md |  2 +-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/app_dart/lib/src/model/firestore/presubmit_check.dart b/app_dart/lib/src/model/firestore/presubmit_check.dart
index 6fc2673d1..a19d0e7ed 100644
--- a/app_dart/lib/src/model/firestore/presubmit_check.dart
+++ b/app_dart/lib/src/model/firestore/presubmit_check.dart
@@ -233,6 +233,14 @@ final class PresubmitCheck extends AppDocument<PresubmitCheck> {
     fields[fieldEndTime] = endTime.toValue();
   }
 
+  set buildNumber(int? buildNumber) {
+    if (buildNumber == null) {
+      fields.remove(fieldBuildNumber);
+    } else {
+      fields[fieldBuildNumber] = buildNumber.toValue();
+    }
+  }
+
   set summary(String? summary) {
     if (summary == null) {
       fields.remove(fieldSummary);
diff --git a/app_dart/test/model/firestore/presubmit_check_test.dart b/app_dart/test/model/firestore/presubmit_check_test.dart
index db89b824a..b2649a4fb 100644
--- a/app_dart/test/model/firestore/presubmit_check_test.dart
+++ b/app_dart/test/model/firestore/presubmit_check_test.dart
@@ -169,5 +169,19 @@ void main() {
 
       expect(check.status, TaskStatus.succeeded);
     });
+
+    test('buildNumber setter updates fields', () {
+      final check = PresubmitCheck.init(
+        buildName: 'linux',
+        checkRunId: 123,
+        creationTime: 1000,
+      );
+
+      check.buildNumber = 789;
+      expect(check.buildNumber, 789);
+
+      check.buildNumber = null;
+      expect(check.buildNumber, isNull);
+    });
   });
 }
diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
index 28eee6892..1ca7b3d36 100644
--- a/conductor/tracks/add_build_number_20260212/plan.md
+++ b/conductor/tracks/add_build_number_20260212/plan.md
@@ -10,7 +10,7 @@ This phase focuses on updating the internal and external data models to support
     - [ ] Add `int? buildNumber` to `PresubmitCheckState` class in `app_dart/lib/src/model/common/presubmit_check_state.dart`.
     - [ ] Update `BuildToPresubmitCheckState` extension to map `number` from `bbv2.Build` to `buildNumber`.
     - [ ] Update existing tests to reflect constructor changes.
-- [ ] Task: Update `PresubmitCheck` Firestore Model
+- [x] Task: Update `PresubmitCheck` Firestore Model
     - [ ] Add `fieldBuildNumber` constant and `buildNumber` getter/setter to `PresubmitCheck` in `app_dart/lib/src/model/firestore/presubmit_check.dart`.
     - [ ] Update `fromDocument`, `init`, and `toJson` (or equivalent) to handle the new field.
     - [ ] Add unit tests for serialization/deserialization of `buildNumber`.

From fe0409bc2b380c23acf0728e84732925e5f3b8db Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:08:01 -0800
Subject: [PATCH 04/14] feat(model): Add buildNumber to PresubmitCheckResponse
 RPC Model

Task: Update PresubmitCheckResponse RPC Model
Summary: Added buildNumber to PresubmitCheckResponse and configured JSON serialization to omit null fields.
Files: packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart, packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.g.dart, packages/cocoon_common/test/presubmit_check_response_test.dart
Why: To expose the LUCI build number in the API responses for presubmit checks.
---
 .../tracks/add_build_number_20260212/plan.md  |  2 +-
 .../rpc_model/presubmit_check_response.dart   | 10 ++++-
 .../rpc_model/presubmit_check_response.g.dart |  9 ++--
 .../test/presubmit_check_response_test.dart   | 41 +++++++++++++++++++
 4 files changed, 57 insertions(+), 5 deletions(-)
 create mode 100644 packages/cocoon_common/test/presubmit_check_response_test.dart

diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
index 1ca7b3d36..e1a18608e 100644
--- a/conductor/tracks/add_build_number_20260212/plan.md
+++ b/conductor/tracks/add_build_number_20260212/plan.md
@@ -14,7 +14,7 @@ This phase focuses on updating the internal and external data models to support
     - [ ] Add `fieldBuildNumber` constant and `buildNumber` getter/setter to `PresubmitCheck` in `app_dart/lib/src/model/firestore/presubmit_check.dart`.
     - [ ] Update `fromDocument`, `init`, and `toJson` (or equivalent) to handle the new field.
     - [ ] Add unit tests for serialization/deserialization of `buildNumber`.
-- [ ] Task: Update `PresubmitCheckResponse` RPC Model
+- [x] Task: Update `PresubmitCheckResponse` RPC Model
     - [ ] Add `int? buildNumber` to `PresubmitCheckResponse` in `packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart`.
     - [ ] Run `dart run build_runner build --delete-conflicting-outputs` in `packages/cocoon_common/` to regenerate JSON serialization code.
     - [ ] Add unit tests for the RPC model.
diff --git a/packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart b/packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart
index 4338d0728..4d6b9b444 100644
--- a/packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart
+++ b/packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart
@@ -10,7 +10,11 @@ import 'base.dart';
 part 'presubmit_check_response.g.dart';
 
 /// RPC model for a presubmit check.
-@JsonSerializable(checked: true, fieldRename: FieldRename.snake)
+@JsonSerializable(
+  checked: true,
+  fieldRename: FieldRename.snake,
+  includeIfNull: false,
+)
 @immutable
 final class PresubmitCheckResponse extends Model {
   /// Creates a [PresubmitCheckResponse] with the given properties.
@@ -22,6 +26,7 @@ final class PresubmitCheckResponse extends Model {
     this.endTime,
     required this.status,
     this.summary,
+    this.buildNumber,
   });
 
   /// Creates a [PresubmitCheckResponse] from [json] representation.
@@ -54,6 +59,9 @@ final class PresubmitCheckResponse extends Model {
   /// A brief summary of the check result or link to logs.
   final String? summary;
 
+  /// The LUCI build number.
+  final int? buildNumber;
+
   @override
   Map<String, Object?> toJson() => _$PresubmitCheckResponseToJson(this);
 }
diff --git a/packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.g.dart b/packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.g.dart
index b2f78a435..e4cbf60c6 100644
--- a/packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.g.dart
+++ b/packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.g.dart
@@ -23,6 +23,7 @@ PresubmitCheckResponse _$PresubmitCheckResponseFromJson(
       endTime: $checkedConvert('end_time', (v) => (v as num?)?.toInt()),
       status: $checkedConvert('status', (v) => v as String),
       summary: $checkedConvert('summary', (v) => v as String?),
+      buildNumber: $checkedConvert('build_number', (v) => (v as num?)?.toInt()),
     );
     return val;
   },
@@ -32,6 +33,7 @@ PresubmitCheckResponse _$PresubmitCheckResponseFromJson(
     'creationTime': 'creation_time',
     'startTime': 'start_time',
     'endTime': 'end_time',
+    'buildNumber': 'build_number',
   },
 );
 
@@ -41,8 +43,9 @@ Map<String, dynamic> _$PresubmitCheckResponseToJson(
   'attempt_number': instance.attemptNumber,
   'build_name': instance.buildName,
   'creation_time': instance.creationTime,
-  'start_time': instance.startTime,
-  'end_time': instance.endTime,
+  'start_time': ?instance.startTime,
+  'end_time': ?instance.endTime,
   'status': instance.status,
-  'summary': instance.summary,
+  'summary': ?instance.summary,
+  'build_number': ?instance.buildNumber,
 };
diff --git a/packages/cocoon_common/test/presubmit_check_response_test.dart b/packages/cocoon_common/test/presubmit_check_response_test.dart
new file mode 100644
index 000000000..d77f62bf8
--- /dev/null
+++ b/packages/cocoon_common/test/presubmit_check_response_test.dart
@@ -0,0 +1,41 @@
+// Copyright 2025 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:cocoon_common/rpc_model.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('PresubmitCheckResponse', () {
+    test('toJson and fromJson handles buildNumber', () {
+      final json = {
+        'attempt_number': 1,
+        'build_name': 'linux',
+        'creation_time': 1000,
+        'status': 'succeeded',
+        'build_number': 456,
+      };
+
+      final response = PresubmitCheckResponse.fromJson(json);
+      expect(response.buildNumber, 456);
+
+      final backToJson = response.toJson();
+      expect(backToJson['build_number'], 456);
+    });
+
+    test('toJson and fromJson handles null buildNumber', () {
+      final json = {
+        'attempt_number': 1,
+        'build_name': 'linux',
+        'creation_time': 1000,
+        'status': 'succeeded',
+      };
+
+      final response = PresubmitCheckResponse.fromJson(json);
+      expect(response.buildNumber, isNull);
+
+      final backToJson = response.toJson();
+      expect(backToJson.containsKey('build_number'), isFalse);
+    });
+  });
+}

From 539f12a274ee9e751115ad7de4288fed6f616d3c Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:11:49 -0800
Subject: [PATCH 05/14] conductor(checkpoint): Phase Complete: Model Updates

---
 conductor/tracks.md                           |  5 +++
 .../tracks/add_build_number_20260212/index.md |  5 +++
 .../add_build_number_20260212/metadata.json   |  8 +++++
 .../tracks/add_build_number_20260212/plan.md  |  2 +-
 .../tracks/add_build_number_20260212/spec.md  | 34 +++++++++++++++++++
 5 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 conductor/tracks/add_build_number_20260212/index.md
 create mode 100644 conductor/tracks/add_build_number_20260212/metadata.json
 create mode 100644 conductor/tracks/add_build_number_20260212/spec.md

diff --git a/conductor/tracks.md b/conductor/tracks.md
index 6ee7e7968..b76255b8c 100644
--- a/conductor/tracks.md
+++ b/conductor/tracks.md
@@ -10,3 +10,8 @@
 - [~] **Track: Build a Merge Queue Dashboard**
 *Link: [./tracks/merge_queue_dashboard_20260205/](./tracks/merge_queue_dashboard_20260205/)*
 
+---
+
+- [~] **Track: Add optional buildNumber to presubmitCheck and fill it on processing checkrun completed**
+*Link: [./tracks/add_build_number_20260212/](./tracks/add_build_number_20260212/)*
+
diff --git a/conductor/tracks/add_build_number_20260212/index.md b/conductor/tracks/add_build_number_20260212/index.md
new file mode 100644
index 000000000..1b8314d4f
--- /dev/null
+++ b/conductor/tracks/add_build_number_20260212/index.md
@@ -0,0 +1,5 @@
+# Track add_build_number_20260212 Context
+
+- [Specification](./spec.md)
+- [Implementation Plan](./plan.md)
+- [Metadata](./metadata.json)
diff --git a/conductor/tracks/add_build_number_20260212/metadata.json b/conductor/tracks/add_build_number_20260212/metadata.json
new file mode 100644
index 000000000..08ff09314
--- /dev/null
+++ b/conductor/tracks/add_build_number_20260212/metadata.json
@@ -0,0 +1,8 @@
+{
+  "track_id": "add_build_number_20260212",
+  "type": "feature",
+  "status": "new",
+  "created_at": "2026-02-12T12:00:00Z",
+  "updated_at": "2026-02-12T12:00:00Z",
+  "description": "Add optional buildNumber to presubmitCheck and fill it on processing checkrun completed"
+}
diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
index e1a18608e..0ce76e60e 100644
--- a/conductor/tracks/add_build_number_20260212/plan.md
+++ b/conductor/tracks/add_build_number_20260212/plan.md
@@ -18,7 +18,7 @@ This phase focuses on updating the internal and external data models to support
     - [ ] Add `int? buildNumber` to `PresubmitCheckResponse` in `packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart`.
     - [ ] Run `dart run build_runner build --delete-conflicting-outputs` in `packages/cocoon_common/` to regenerate JSON serialization code.
     - [ ] Add unit tests for the RPC model.
-- [ ] Task: Conductor - User Manual Verification 'Model Updates' (Protocol in workflow.md)
+- [~] Task: Conductor - User Manual Verification 'Model Updates' (Protocol in workflow.md)
 
 ## Phase 2: Backend Logic and API Updates
 
diff --git a/conductor/tracks/add_build_number_20260212/spec.md b/conductor/tracks/add_build_number_20260212/spec.md
new file mode 100644
index 000000000..e6f483eec
--- /dev/null
+++ b/conductor/tracks/add_build_number_20260212/spec.md
@@ -0,0 +1,34 @@
+# Specification: Add `buildNumber` to `PresubmitCheck`
+
+## Overview
+Currently, the `PresubmitCheck` model in Cocoon's Firestore and the corresponding RPC response (`PresubmitCheckResponse`) do not include the canonical LUCI build number. This makes it difficult for backend processes to uniquely identify and link to specific build attempts. This feature adds an optional `buildNumber` field to these models, as well as the intermediate `PresubmitCheckState`, ensuring it is populated when a GitHub `check_run` completion event is processed.
+
+## Goals
+- **Improve Traceability:** Provide a direct reference to the LUCI build number in the backend data.
+- **Enhanced Context:** Ensure the backend records contain the canonical build number for better auditing and debugging.
+- **Future Support:** Lay the groundwork for re-running specific builds using their build number and for future UI integrations.
+
+## Functional Requirements
+1.  **Intermediate State Update:** Add a `buildNumber` field (integer, optional) to `PresubmitCheckState` in `app_dart/lib/src/model/common/presubmit_check_state.dart`.
+2.  **Firestore Model Update:** Add a `buildNumber` field (integer, optional) to the `PresubmitCheck` document in Firestore.
+3.  **RPC Model Update:** Add a `buildNumber` field (integer, optional) to the `PresubmitCheckResponse` RPC model.
+4.  **Data Population:** Update `UnifiedCheckRun.markConclusion` (or the relevant handler for `check_run` completion) to:
+    -   Fetch the canonical build number from the LUCI BuildBucket API if it's not already available in the incoming `check_run` state.
+    -   Store this `buildNumber` in the `PresubmitCheck` document.
+5.  **Handling Missing Data:** Older check runs or runs where the build number cannot be retrieved should have the `buildNumber` field set to `null` or omitted.
+
+## Non-Functional Requirements
+- **Performance:** Fetching the build number from BuildBucket should not significantly delay the processing of `check_run` events.
+- **Reliability:** If fetching the build number fails, the system should still record the completion status without the build number rather than failing the entire transaction.
+
+## Acceptance Criteria
+- [ ] `PresubmitCheckState` includes a `buildNumber` field.
+- [ ] `PresubmitCheck` documents in Firestore can store a `buildNumber`.
+- [ ] `PresubmitCheckResponse` JSON includes a `buildNumber` field when available.
+- [ ] When a `check_run` completes, the `buildNumber` is correctly retrieved and stored.
+- [ ] Existing check runs without a build number continue to work (field is null).
+
+## Out of Scope
+- **Dashboard Integration:** Updating the dashboard UI to display or use the build number is out of scope for this track.
+- **Backfilling:** Backfilling build numbers for historical check runs.
+- **Rerun Logic:** Implementing the "re-run by build number" functionality.

From c104b03c1951607337f66dbff58eef0d188048b6 Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:12:02 -0800
Subject: [PATCH 06/14] conductor(plan): Mark phase 'Model Updates' as complete

---
 .../tracks/add_build_number_20260212/plan.md  | 22 +++++++++----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
index 0ce76e60e..cd3baf007 100644
--- a/conductor/tracks/add_build_number_20260212/plan.md
+++ b/conductor/tracks/add_build_number_20260212/plan.md
@@ -2,23 +2,23 @@
 
 This plan outlines the steps to add an optional `buildNumber` field across the Cocoon backend models and ensure it is populated during the check run completion process.
 
-## Phase 1: Model Updates
+## Phase 1: Model Updates [checkpoint: 539f12a]
 
 This phase focuses on updating the internal and external data models to support the new `buildNumber` field.
 
 - [x] Task: Update `PresubmitCheckState` Model
-    - [ ] Add `int? buildNumber` to `PresubmitCheckState` class in `app_dart/lib/src/model/common/presubmit_check_state.dart`.
-    - [ ] Update `BuildToPresubmitCheckState` extension to map `number` from `bbv2.Build` to `buildNumber`.
-    - [ ] Update existing tests to reflect constructor changes.
+    - [x] Add `int? buildNumber` to `PresubmitCheckState` class in `app_dart/lib/src/model/common/presubmit_check_state.dart`.
+    - [x] Update `BuildToPresubmitCheckState` extension to map `number` from `bbv2.Build` to `buildNumber`.
+    - [x] Update existing tests to reflect constructor changes.
 - [x] Task: Update `PresubmitCheck` Firestore Model
-    - [ ] Add `fieldBuildNumber` constant and `buildNumber` getter/setter to `PresubmitCheck` in `app_dart/lib/src/model/firestore/presubmit_check.dart`.
-    - [ ] Update `fromDocument`, `init`, and `toJson` (or equivalent) to handle the new field.
-    - [ ] Add unit tests for serialization/deserialization of `buildNumber`.
+    - [x] Add `fieldBuildNumber` constant and `buildNumber` getter/setter to `PresubmitCheck` in `app_dart/lib/src/model/firestore/presubmit_check.dart`.
+    - [x] Update `fromDocument`, `init`, and `toJson` (or equivalent) to handle the new field.
+    - [x] Add unit tests for serialization/deserialization of `buildNumber`.
 - [x] Task: Update `PresubmitCheckResponse` RPC Model
-    - [ ] Add `int? buildNumber` to `PresubmitCheckResponse` in `packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart`.
-    - [ ] Run `dart run build_runner build --delete-conflicting-outputs` in `packages/cocoon_common/` to regenerate JSON serialization code.
-    - [ ] Add unit tests for the RPC model.
-- [~] Task: Conductor - User Manual Verification 'Model Updates' (Protocol in workflow.md)
+    - [x] Add `int? buildNumber` to `PresubmitCheckResponse` in `packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart`.
+    - [x] Run `dart run build_runner build --delete-conflicting-outputs` in `packages/cocoon_common/` to regenerate JSON serialization code.
+    - [x] Add unit tests for the RPC model.
+- [x] Task: Conductor - User Manual Verification 'Model Updates' (Protocol in workflow.md)
 
 ## Phase 2: Backend Logic and API Updates
 

From aef84ca1eb89e2d1ce6af5363fcdace652a9556f Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:12:30 -0800
Subject: [PATCH 07/14] feat(service): Store buildNumber in markConclusion

Task: Update UnifiedCheckRun.markConclusion Logic
Summary: Updated markConclusion to store the buildNumber from PresubmitCheckState into the Firestore PresubmitCheck document. Updated relevant tests.
Files: app_dart/lib/src/service/firestore/unified_check_run.dart, app_dart/test/service/firestore/unified_check_run_test.dart
Why: To ensure the LUCI build number is persisted in Firestore when a presubmit check completes.
---
 app_dart/lib/src/service/firestore/unified_check_run.dart   | 1 +
 app_dart/test/service/firestore/unified_check_run_test.dart | 2 ++
 conductor/tracks/add_build_number_20260212/plan.md          | 2 +-
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/app_dart/lib/src/service/firestore/unified_check_run.dart b/app_dart/lib/src/service/firestore/unified_check_run.dart
index 6b33b9a8d..8e26dddbb 100644
--- a/app_dart/lib/src/service/firestore/unified_check_run.dart
+++ b/app_dart/lib/src/service/firestore/unified_check_run.dart
@@ -475,6 +475,7 @@ final class UnifiedCheckRun {
         presubmitGuard.failedBuilds = failed;
         presubmitCheck.endTime = state.endTime!;
         presubmitCheck.summary = state.summary;
+        presubmitCheck.buildNumber = state.buildNumber;
       }
       builds[state.buildName] = status;
       presubmitGuard.builds = builds;
diff --git a/app_dart/test/service/firestore/unified_check_run_test.dart b/app_dart/test/service/firestore/unified_check_run_test.dart
index 7db68690d..e6a7f0cf1 100644
--- a/app_dart/test/service/firestore/unified_check_run_test.dart
+++ b/app_dart/test/service/firestore/unified_check_run_test.dart
@@ -172,6 +172,7 @@ void main() {
           attemptNumber: 1,
           startTime: 2000,
           endTime: 3000,
+          buildNumber: 456,
         );
 
         final result = await UnifiedCheckRun.markConclusion(
@@ -194,6 +195,7 @@ void main() {
         );
         expect(checkDoc.status, TaskStatus.succeeded);
         expect(checkDoc.endTime, 3000);
+        expect(checkDoc.buildNumber, 456);
       });
 
       test(
diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
index cd3baf007..125f7a6af 100644
--- a/conductor/tracks/add_build_number_20260212/plan.md
+++ b/conductor/tracks/add_build_number_20260212/plan.md
@@ -24,7 +24,7 @@ This phase focuses on updating the internal and external data models to support
 
 This phase integrates the new field into the core logic and ensures it is returned by the API.
 
-- [ ] Task: Update `UnifiedCheckRun.markConclusion` Logic
+- [x] Task: Update `UnifiedCheckRun.markConclusion` Logic
     - [ ] Update `markConclusion` in `app_dart/lib/src/service/firestore/unified_check_run.dart` to assign `state.buildNumber` to `presubmitCheck.buildNumber`.
     - [ ] Add/update tests in `app_dart/test/service/firestore/unified_check_run_test.dart` to verify the build number is correctly saved to Firestore.
 - [ ] Task: Update `GetPresubmitChecks` API Handler

From 932f6b03d428025ac1add842c63e303b5c86c717 Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:13:05 -0800
Subject: [PATCH 08/14] feat(api): Return buildNumber in GetPresubmitChecks

Task: Update GetPresubmitChecks API Handler
Summary: Updated the GetPresubmitChecks API handler to include the buildNumber from the Firestore PresubmitCheck document in the PresubmitCheckResponse. Updated relevant tests.
Files: app_dart/lib/src/request_handlers/get_presubmit_checks.dart, app_dart/test/request_handlers/get_presubmit_checks_test.dart
Why: To expose the LUCI build number in the API for consumption by the dashboard.
---
 app_dart/lib/src/request_handlers/get_presubmit_checks.dart   | 1 +
 app_dart/test/request_handlers/get_presubmit_checks_test.dart | 2 ++
 conductor/tracks/add_build_number_20260212/plan.md            | 2 +-
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/app_dart/lib/src/request_handlers/get_presubmit_checks.dart b/app_dart/lib/src/request_handlers/get_presubmit_checks.dart
index af074107a..3f3ced517 100644
--- a/app_dart/lib/src/request_handlers/get_presubmit_checks.dart
+++ b/app_dart/lib/src/request_handlers/get_presubmit_checks.dart
@@ -88,6 +88,7 @@ final class GetPresubmitChecks extends ApiRequestHandler {
           endTime: check.endTime,
           status: check.status.value,
           summary: check.summary,
+          buildNumber: check.buildNumber,
         ),
     ];
 
diff --git a/app_dart/test/request_handlers/get_presubmit_checks_test.dart b/app_dart/test/request_handlers/get_presubmit_checks_test.dart
index fd6cc77f9..df53c4037 100644
--- a/app_dart/test/request_handlers/get_presubmit_checks_test.dart
+++ b/app_dart/test/request_handlers/get_presubmit_checks_test.dart
@@ -85,6 +85,7 @@ void main() {
         startTime: 110,
         endTime: 120,
         summary: 'all good',
+        buildNumber: 456,
       );
       await firestoreService.writeViaTransaction(
         documentsToWrites([check], exists: false),
@@ -101,6 +102,7 @@ void main() {
       expect(checks[0].attemptNumber, 1);
       expect(checks[0].buildName, 'linux');
       expect(checks[0].status, 'Succeeded');
+      expect(checks[0].buildNumber, 456);
     });
 
     test('returns multiple checks in descending order', () async {
diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
index 125f7a6af..c234a2f73 100644
--- a/conductor/tracks/add_build_number_20260212/plan.md
+++ b/conductor/tracks/add_build_number_20260212/plan.md
@@ -27,7 +27,7 @@ This phase integrates the new field into the core logic and ensures it is return
 - [x] Task: Update `UnifiedCheckRun.markConclusion` Logic
     - [ ] Update `markConclusion` in `app_dart/lib/src/service/firestore/unified_check_run.dart` to assign `state.buildNumber` to `presubmitCheck.buildNumber`.
     - [ ] Add/update tests in `app_dart/test/service/firestore/unified_check_run_test.dart` to verify the build number is correctly saved to Firestore.
-- [ ] Task: Update `GetPresubmitChecks` API Handler
+- [x] Task: Update `GetPresubmitChecks` API Handler
     - [ ] Update `GetPresubmitChecks` in `app_dart/lib/src/request_handlers/get_presubmit_checks.dart` to map `PresubmitCheck.buildNumber` to `PresubmitCheckResponse.buildNumber`.
     - [ ] Update handler tests to verify the API response contains the build number.
 - [ ] Task: Conductor - User Manual Verification 'Backend Logic and API Updates' (Protocol in workflow.md)

From ead405d6c1ca8990fb2af836e25d3715c3a7f77d Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:14:32 -0800
Subject: [PATCH 09/14] conductor(checkpoint): Phase Complete: Backend Logic
 and API Updates

---
 conductor/tracks/add_build_number_20260212/plan.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
index c234a2f73..dcd73542b 100644
--- a/conductor/tracks/add_build_number_20260212/plan.md
+++ b/conductor/tracks/add_build_number_20260212/plan.md
@@ -30,4 +30,4 @@ This phase integrates the new field into the core logic and ensures it is return
 - [x] Task: Update `GetPresubmitChecks` API Handler
     - [ ] Update `GetPresubmitChecks` in `app_dart/lib/src/request_handlers/get_presubmit_checks.dart` to map `PresubmitCheck.buildNumber` to `PresubmitCheckResponse.buildNumber`.
     - [ ] Update handler tests to verify the API response contains the build number.
-- [ ] Task: Conductor - User Manual Verification 'Backend Logic and API Updates' (Protocol in workflow.md)
+- [~] Task: Conductor - User Manual Verification 'Backend Logic and API Updates' (Protocol in workflow.md)

From 072a337fd2fa3a9c60d0ba7e42c8a74e47f2a104 Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:14:43 -0800
Subject: [PATCH 10/14] conductor(plan): Mark phase 'Backend Logic and API
 Updates' as complete

---
 conductor/tracks/add_build_number_20260212/plan.md | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
index dcd73542b..b376f3088 100644
--- a/conductor/tracks/add_build_number_20260212/plan.md
+++ b/conductor/tracks/add_build_number_20260212/plan.md
@@ -20,14 +20,14 @@ This phase focuses on updating the internal and external data models to support
     - [x] Add unit tests for the RPC model.
 - [x] Task: Conductor - User Manual Verification 'Model Updates' (Protocol in workflow.md)
 
-## Phase 2: Backend Logic and API Updates
+## Phase 2: Backend Logic and API Updates [checkpoint: ead405d]
 
 This phase integrates the new field into the core logic and ensures it is returned by the API.
 
 - [x] Task: Update `UnifiedCheckRun.markConclusion` Logic
-    - [ ] Update `markConclusion` in `app_dart/lib/src/service/firestore/unified_check_run.dart` to assign `state.buildNumber` to `presubmitCheck.buildNumber`.
-    - [ ] Add/update tests in `app_dart/test/service/firestore/unified_check_run_test.dart` to verify the build number is correctly saved to Firestore.
+    - [x] Update `markConclusion` in `app_dart/lib/src/service/firestore/unified_check_run.dart` to assign `state.buildNumber` to `presubmitCheck.buildNumber`.
+    - [x] Add/update tests in `app_dart/test/service/firestore/unified_check_run_test.dart` to verify the build number is correctly saved to Firestore.
 - [x] Task: Update `GetPresubmitChecks` API Handler
-    - [ ] Update `GetPresubmitChecks` in `app_dart/lib/src/request_handlers/get_presubmit_checks.dart` to map `PresubmitCheck.buildNumber` to `PresubmitCheckResponse.buildNumber`.
-    - [ ] Update handler tests to verify the API response contains the build number.
-- [~] Task: Conductor - User Manual Verification 'Backend Logic and API Updates' (Protocol in workflow.md)
+    - [x] Update `GetPresubmitChecks` in `app_dart/lib/src/request_handlers/get_presubmit_checks.dart` to map `PresubmitCheck.buildNumber` to `PresubmitCheckResponse.buildNumber`.
+    - [x] Update handler tests to verify the API response contains the build number.
+- [x] Task: Conductor - User Manual Verification 'Backend Logic and API Updates' (Protocol in workflow.md)

From 9be9c902e4dab7d1fa8922fc83344b8cfa9104a0 Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:14:51 -0800
Subject: [PATCH 11/14] chore(conductor): Mark track 'Add optional buildNumber
 to presubmitCheck and fill it on processing checkrun completed' as complete

---
 conductor/tracks.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/conductor/tracks.md b/conductor/tracks.md
index b76255b8c..6dada8c0d 100644
--- a/conductor/tracks.md
+++ b/conductor/tracks.md
@@ -12,6 +12,6 @@
 
 ---
 
-- [~] **Track: Add optional buildNumber to presubmitCheck and fill it on processing checkrun completed**
+- [x] **Track: Add optional buildNumber to presubmitCheck and fill it on processing checkrun completed**
 *Link: [./tracks/add_build_number_20260212/](./tracks/add_build_number_20260212/)*
 

From 2445bb797bf232e3e87b336c0b7f9e5b48f45b75 Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:21:36 -0800
Subject: [PATCH 12/14] chore(conductor): Archive track 'Add optional
 buildNumber to presubmitCheck and fill it on processing checkrun completed'

---
 .../add_build_number_20260212/index.md        |  5 +++
 .../add_build_number_20260212/metadata.json   |  8 +++++
 .../archive/add_build_number_20260212/plan.md | 33 ++++++++++++++++++
 .../archive/add_build_number_20260212/spec.md | 34 +++++++++++++++++++
 conductor/tracks.md                           |  4 ---
 5 files changed, 80 insertions(+), 4 deletions(-)
 create mode 100644 conductor/archive/add_build_number_20260212/index.md
 create mode 100644 conductor/archive/add_build_number_20260212/metadata.json
 create mode 100644 conductor/archive/add_build_number_20260212/plan.md
 create mode 100644 conductor/archive/add_build_number_20260212/spec.md

diff --git a/conductor/archive/add_build_number_20260212/index.md b/conductor/archive/add_build_number_20260212/index.md
new file mode 100644
index 000000000..1b8314d4f
--- /dev/null
+++ b/conductor/archive/add_build_number_20260212/index.md
@@ -0,0 +1,5 @@
+# Track add_build_number_20260212 Context
+
+- [Specification](./spec.md)
+- [Implementation Plan](./plan.md)
+- [Metadata](./metadata.json)
diff --git a/conductor/archive/add_build_number_20260212/metadata.json b/conductor/archive/add_build_number_20260212/metadata.json
new file mode 100644
index 000000000..08ff09314
--- /dev/null
+++ b/conductor/archive/add_build_number_20260212/metadata.json
@@ -0,0 +1,8 @@
+{
+  "track_id": "add_build_number_20260212",
+  "type": "feature",
+  "status": "new",
+  "created_at": "2026-02-12T12:00:00Z",
+  "updated_at": "2026-02-12T12:00:00Z",
+  "description": "Add optional buildNumber to presubmitCheck and fill it on processing checkrun completed"
+}
diff --git a/conductor/archive/add_build_number_20260212/plan.md b/conductor/archive/add_build_number_20260212/plan.md
new file mode 100644
index 000000000..b376f3088
--- /dev/null
+++ b/conductor/archive/add_build_number_20260212/plan.md
@@ -0,0 +1,33 @@
+# Implementation Plan: Add `buildNumber` to `PresubmitCheck`
+
+This plan outlines the steps to add an optional `buildNumber` field across the Cocoon backend models and ensure it is populated during the check run completion process.
+
+## Phase 1: Model Updates [checkpoint: 539f12a]
+
+This phase focuses on updating the internal and external data models to support the new `buildNumber` field.
+
+- [x] Task: Update `PresubmitCheckState` Model
+    - [x] Add `int? buildNumber` to `PresubmitCheckState` class in `app_dart/lib/src/model/common/presubmit_check_state.dart`.
+    - [x] Update `BuildToPresubmitCheckState` extension to map `number` from `bbv2.Build` to `buildNumber`.
+    - [x] Update existing tests to reflect constructor changes.
+- [x] Task: Update `PresubmitCheck` Firestore Model
+    - [x] Add `fieldBuildNumber` constant and `buildNumber` getter/setter to `PresubmitCheck` in `app_dart/lib/src/model/firestore/presubmit_check.dart`.
+    - [x] Update `fromDocument`, `init`, and `toJson` (or equivalent) to handle the new field.
+    - [x] Add unit tests for serialization/deserialization of `buildNumber`.
+- [x] Task: Update `PresubmitCheckResponse` RPC Model
+    - [x] Add `int? buildNumber` to `PresubmitCheckResponse` in `packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart`.
+    - [x] Run `dart run build_runner build --delete-conflicting-outputs` in `packages/cocoon_common/` to regenerate JSON serialization code.
+    - [x] Add unit tests for the RPC model.
+- [x] Task: Conductor - User Manual Verification 'Model Updates' (Protocol in workflow.md)
+
+## Phase 2: Backend Logic and API Updates [checkpoint: ead405d]
+
+This phase integrates the new field into the core logic and ensures it is returned by the API.
+
+- [x] Task: Update `UnifiedCheckRun.markConclusion` Logic
+    - [x] Update `markConclusion` in `app_dart/lib/src/service/firestore/unified_check_run.dart` to assign `state.buildNumber` to `presubmitCheck.buildNumber`.
+    - [x] Add/update tests in `app_dart/test/service/firestore/unified_check_run_test.dart` to verify the build number is correctly saved to Firestore.
+- [x] Task: Update `GetPresubmitChecks` API Handler
+    - [x] Update `GetPresubmitChecks` in `app_dart/lib/src/request_handlers/get_presubmit_checks.dart` to map `PresubmitCheck.buildNumber` to `PresubmitCheckResponse.buildNumber`.
+    - [x] Update handler tests to verify the API response contains the build number.
+- [x] Task: Conductor - User Manual Verification 'Backend Logic and API Updates' (Protocol in workflow.md)
diff --git a/conductor/archive/add_build_number_20260212/spec.md b/conductor/archive/add_build_number_20260212/spec.md
new file mode 100644
index 000000000..e6f483eec
--- /dev/null
+++ b/conductor/archive/add_build_number_20260212/spec.md
@@ -0,0 +1,34 @@
+# Specification: Add `buildNumber` to `PresubmitCheck`
+
+## Overview
+Currently, the `PresubmitCheck` model in Cocoon's Firestore and the corresponding RPC response (`PresubmitCheckResponse`) do not include the canonical LUCI build number. This makes it difficult for backend processes to uniquely identify and link to specific build attempts. This feature adds an optional `buildNumber` field to these models, as well as the intermediate `PresubmitCheckState`, ensuring it is populated when a GitHub `check_run` completion event is processed.
+
+## Goals
+- **Improve Traceability:** Provide a direct reference to the LUCI build number in the backend data.
+- **Enhanced Context:** Ensure the backend records contain the canonical build number for better auditing and debugging.
+- **Future Support:** Lay the groundwork for re-running specific builds using their build number and for future UI integrations.
+
+## Functional Requirements
+1.  **Intermediate State Update:** Add a `buildNumber` field (integer, optional) to `PresubmitCheckState` in `app_dart/lib/src/model/common/presubmit_check_state.dart`.
+2.  **Firestore Model Update:** Add a `buildNumber` field (integer, optional) to the `PresubmitCheck` document in Firestore.
+3.  **RPC Model Update:** Add a `buildNumber` field (integer, optional) to the `PresubmitCheckResponse` RPC model.
+4.  **Data Population:** Update `UnifiedCheckRun.markConclusion` (or the relevant handler for `check_run` completion) to:
+    -   Fetch the canonical build number from the LUCI BuildBucket API if it's not already available in the incoming `check_run` state.
+    -   Store this `buildNumber` in the `PresubmitCheck` document.
+5.  **Handling Missing Data:** Older check runs or runs where the build number cannot be retrieved should have the `buildNumber` field set to `null` or omitted.
+
+## Non-Functional Requirements
+- **Performance:** Fetching the build number from BuildBucket should not significantly delay the processing of `check_run` events.
+- **Reliability:** If fetching the build number fails, the system should still record the completion status without the build number rather than failing the entire transaction.
+
+## Acceptance Criteria
+- [ ] `PresubmitCheckState` includes a `buildNumber` field.
+- [ ] `PresubmitCheck` documents in Firestore can store a `buildNumber`.
+- [ ] `PresubmitCheckResponse` JSON includes a `buildNumber` field when available.
+- [ ] When a `check_run` completes, the `buildNumber` is correctly retrieved and stored.
+- [ ] Existing check runs without a build number continue to work (field is null).
+
+## Out of Scope
+- **Dashboard Integration:** Updating the dashboard UI to display or use the build number is out of scope for this track.
+- **Backfilling:** Backfilling build numbers for historical check runs.
+- **Rerun Logic:** Implementing the "re-run by build number" functionality.
diff --git a/conductor/tracks.md b/conductor/tracks.md
index 6dada8c0d..f8dbf0768 100644
--- a/conductor/tracks.md
+++ b/conductor/tracks.md
@@ -10,8 +10,4 @@
 - [~] **Track: Build a Merge Queue Dashboard**
 *Link: [./tracks/merge_queue_dashboard_20260205/](./tracks/merge_queue_dashboard_20260205/)*
 
----
-
-- [x] **Track: Add optional buildNumber to presubmitCheck and fill it on processing checkrun completed**
-*Link: [./tracks/add_build_number_20260212/](./tracks/add_build_number_20260212/)*
 

From 053f1875183ac2aef8ff2478279b5848782a9a25 Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Thu, 12 Feb 2026 17:37:21 -0800
Subject: [PATCH 13/14] chore: delete add_build_number track files and reformat
 a test file.

---
 .../common/presubmit_check_state_test.dart    |  6 ++--
 .../tracks/add_build_number_20260212/index.md |  5 ---
 .../add_build_number_20260212/metadata.json   |  8 -----
 .../tracks/add_build_number_20260212/plan.md  | 33 ------------------
 .../tracks/add_build_number_20260212/spec.md  | 34 -------------------
 5 files changed, 2 insertions(+), 84 deletions(-)
 delete mode 100644 conductor/tracks/add_build_number_20260212/index.md
 delete mode 100644 conductor/tracks/add_build_number_20260212/metadata.json
 delete mode 100644 conductor/tracks/add_build_number_20260212/plan.md
 delete mode 100644 conductor/tracks/add_build_number_20260212/spec.md

diff --git a/app_dart/test/model/common/presubmit_check_state_test.dart b/app_dart/test/model/common/presubmit_check_state_test.dart
index 1519ff9b2..f022bb0d5 100644
--- a/app_dart/test/model/common/presubmit_check_state_test.dart
+++ b/app_dart/test/model/common/presubmit_check_state_test.dart
@@ -2,9 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:cocoon_service/src/model/common/presubmit_check_state.dart';
 import 'package:buildbucket/buildbucket_pb.dart' as bbv2;
 import 'package:cocoon_common/task_status.dart';
+import 'package:cocoon_service/src/model/common/presubmit_check_state.dart';
 import 'package:fixnum/fixnum.dart';
 import 'package:test/test.dart';
 
@@ -18,9 +18,7 @@ void main() {
         startTime: bbv2.Timestamp(seconds: Int64(1000)),
         endTime: bbv2.Timestamp(seconds: Int64(2000)),
         summaryMarkdown: 'Summary',
-        tags: [
-          bbv2.StringPair(key: 'github_checkrun', value: '123'),
-        ],
+        tags: [bbv2.StringPair(key: 'github_checkrun', value: '123')],
       );
 
       final state = build.toPresubmitCheckState();
diff --git a/conductor/tracks/add_build_number_20260212/index.md b/conductor/tracks/add_build_number_20260212/index.md
deleted file mode 100644
index 1b8314d4f..000000000
--- a/conductor/tracks/add_build_number_20260212/index.md
+++ /dev/null
@@ -1,5 +0,0 @@
-# Track add_build_number_20260212 Context
-
-- [Specification](./spec.md)
-- [Implementation Plan](./plan.md)
-- [Metadata](./metadata.json)
diff --git a/conductor/tracks/add_build_number_20260212/metadata.json b/conductor/tracks/add_build_number_20260212/metadata.json
deleted file mode 100644
index 08ff09314..000000000
--- a/conductor/tracks/add_build_number_20260212/metadata.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "track_id": "add_build_number_20260212",
-  "type": "feature",
-  "status": "new",
-  "created_at": "2026-02-12T12:00:00Z",
-  "updated_at": "2026-02-12T12:00:00Z",
-  "description": "Add optional buildNumber to presubmitCheck and fill it on processing checkrun completed"
-}
diff --git a/conductor/tracks/add_build_number_20260212/plan.md b/conductor/tracks/add_build_number_20260212/plan.md
deleted file mode 100644
index b376f3088..000000000
--- a/conductor/tracks/add_build_number_20260212/plan.md
+++ /dev/null
@@ -1,33 +0,0 @@
-# Implementation Plan: Add `buildNumber` to `PresubmitCheck`
-
-This plan outlines the steps to add an optional `buildNumber` field across the Cocoon backend models and ensure it is populated during the check run completion process.
-
-## Phase 1: Model Updates [checkpoint: 539f12a]
-
-This phase focuses on updating the internal and external data models to support the new `buildNumber` field.
-
-- [x] Task: Update `PresubmitCheckState` Model
-    - [x] Add `int? buildNumber` to `PresubmitCheckState` class in `app_dart/lib/src/model/common/presubmit_check_state.dart`.
-    - [x] Update `BuildToPresubmitCheckState` extension to map `number` from `bbv2.Build` to `buildNumber`.
-    - [x] Update existing tests to reflect constructor changes.
-- [x] Task: Update `PresubmitCheck` Firestore Model
-    - [x] Add `fieldBuildNumber` constant and `buildNumber` getter/setter to `PresubmitCheck` in `app_dart/lib/src/model/firestore/presubmit_check.dart`.
-    - [x] Update `fromDocument`, `init`, and `toJson` (or equivalent) to handle the new field.
-    - [x] Add unit tests for serialization/deserialization of `buildNumber`.
-- [x] Task: Update `PresubmitCheckResponse` RPC Model
-    - [x] Add `int? buildNumber` to `PresubmitCheckResponse` in `packages/cocoon_common/lib/src/rpc_model/presubmit_check_response.dart`.
-    - [x] Run `dart run build_runner build --delete-conflicting-outputs` in `packages/cocoon_common/` to regenerate JSON serialization code.
-    - [x] Add unit tests for the RPC model.
-- [x] Task: Conductor - User Manual Verification 'Model Updates' (Protocol in workflow.md)
-
-## Phase 2: Backend Logic and API Updates [checkpoint: ead405d]
-
-This phase integrates the new field into the core logic and ensures it is returned by the API.
-
-- [x] Task: Update `UnifiedCheckRun.markConclusion` Logic
-    - [x] Update `markConclusion` in `app_dart/lib/src/service/firestore/unified_check_run.dart` to assign `state.buildNumber` to `presubmitCheck.buildNumber`.
-    - [x] Add/update tests in `app_dart/test/service/firestore/unified_check_run_test.dart` to verify the build number is correctly saved to Firestore.
-- [x] Task: Update `GetPresubmitChecks` API Handler
-    - [x] Update `GetPresubmitChecks` in `app_dart/lib/src/request_handlers/get_presubmit_checks.dart` to map `PresubmitCheck.buildNumber` to `PresubmitCheckResponse.buildNumber`.
-    - [x] Update handler tests to verify the API response contains the build number.
-- [x] Task: Conductor - User Manual Verification 'Backend Logic and API Updates' (Protocol in workflow.md)
diff --git a/conductor/tracks/add_build_number_20260212/spec.md b/conductor/tracks/add_build_number_20260212/spec.md
deleted file mode 100644
index e6f483eec..000000000
--- a/conductor/tracks/add_build_number_20260212/spec.md
+++ /dev/null
@@ -1,34 +0,0 @@
-# Specification: Add `buildNumber` to `PresubmitCheck`
-
-## Overview
-Currently, the `PresubmitCheck` model in Cocoon's Firestore and the corresponding RPC response (`PresubmitCheckResponse`) do not include the canonical LUCI build number. This makes it difficult for backend processes to uniquely identify and link to specific build attempts. This feature adds an optional `buildNumber` field to these models, as well as the intermediate `PresubmitCheckState`, ensuring it is populated when a GitHub `check_run` completion event is processed.
-
-## Goals
-- **Improve Traceability:** Provide a direct reference to the LUCI build number in the backend data.
-- **Enhanced Context:** Ensure the backend records contain the canonical build number for better auditing and debugging.
-- **Future Support:** Lay the groundwork for re-running specific builds using their build number and for future UI integrations.
-
-## Functional Requirements
-1.  **Intermediate State Update:** Add a `buildNumber` field (integer, optional) to `PresubmitCheckState` in `app_dart/lib/src/model/common/presubmit_check_state.dart`.
-2.  **Firestore Model Update:** Add a `buildNumber` field (integer, optional) to the `PresubmitCheck` document in Firestore.
-3.  **RPC Model Update:** Add a `buildNumber` field (integer, optional) to the `PresubmitCheckResponse` RPC model.
-4.  **Data Population:** Update `UnifiedCheckRun.markConclusion` (or the relevant handler for `check_run` completion) to:
-    -   Fetch the canonical build number from the LUCI BuildBucket API if it's not already available in the incoming `check_run` state.
-    -   Store this `buildNumber` in the `PresubmitCheck` document.
-5.  **Handling Missing Data:** Older check runs or runs where the build number cannot be retrieved should have the `buildNumber` field set to `null` or omitted.
-
-## Non-Functional Requirements
-- **Performance:** Fetching the build number from BuildBucket should not significantly delay the processing of `check_run` events.
-- **Reliability:** If fetching the build number fails, the system should still record the completion status without the build number rather than failing the entire transaction.
-
-## Acceptance Criteria
-- [ ] `PresubmitCheckState` includes a `buildNumber` field.
-- [ ] `PresubmitCheck` documents in Firestore can store a `buildNumber`.
-- [ ] `PresubmitCheckResponse` JSON includes a `buildNumber` field when available.
-- [ ] When a `check_run` completes, the `buildNumber` is correctly retrieved and stored.
-- [ ] Existing check runs without a build number continue to work (field is null).
-
-## Out of Scope
-- **Dashboard Integration:** Updating the dashboard UI to display or use the build number is out of scope for this track.
-- **Backfilling:** Backfilling build numbers for historical check runs.
-- **Rerun Logic:** Implementing the "re-run by build number" functionality.

From 1557dabe54c09c1f2b9e3a27c7d37668673b05ba Mon Sep 17 00:00:00 2001
From: Dmitry Grand <dmgr@google.com>
Date: Fri, 13 Feb 2026 10:04:15 -0800
Subject: [PATCH 14/14] Enable test logging for
 `presubmit_check_state_test.dart`.

---
 app_dart/test/model/common/presubmit_check_state_test.dart | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/app_dart/test/model/common/presubmit_check_state_test.dart b/app_dart/test/model/common/presubmit_check_state_test.dart
index f022bb0d5..6d5a4f8ec 100644
--- a/app_dart/test/model/common/presubmit_check_state_test.dart
+++ b/app_dart/test/model/common/presubmit_check_state_test.dart
@@ -4,11 +4,13 @@
 
 import 'package:buildbucket/buildbucket_pb.dart' as bbv2;
 import 'package:cocoon_common/task_status.dart';
+import 'package:cocoon_server_test/test_logging.dart';
 import 'package:cocoon_service/src/model/common/presubmit_check_state.dart';
 import 'package:fixnum/fixnum.dart';
 import 'package:test/test.dart';
 
 void main() {
+  useTestLoggerPerTest();
   group('PresubmitCheckState', () {
     test('BuildToPresubmitCheckState extension maps build number', () {
       final build = bbv2.Build(