Provide bid rejected reason to losing bidders.

Allow scoreAd() return an extra string field 'rejectReason', which
tells why a bid is rejected. Its value is case sensitive. A bidder's
script can use placeholder ${rejectReason} in its debugging loss report
URL's query string, to get the reject reason. If score > 0, the
'rejectReason' value will be ignored (set to default 'not-available')
even if there is one from scoreAd().
Currently component sellers which participate in a top level auction
and act as bidders do not get top level's reject reasons.

Fixed: b/232945640
Bug: b/232945640
Change-Id: Idc0a270252241475863f28e0c212453fef9b29dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3661960
Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Qingxin Wu <qingxinwu@google.com>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1049741}

content/browser/interest_group/auction_runner_unittest.cc

@@ -169,7 +169,8 @@ std::string MakeBidScript(const url::Origin& seller,
                           const std::string& signal_val = "",
                           bool report_post_auction_signals = false,
                           const std::string& debug_loss_report_url = "",
-                          const std::string& debug_win_report_url = "") {
+                          const std::string& debug_win_report_url = "",
+                          bool report_reject_reason = false) {
   // TODO(morlovich): Use JsReplace.
   constexpr char kBidScript[] = R"(
     const seller = "%s";
@@ -180,6 +181,7 @@ std::string MakeBidScript(const url::Origin& seller,
     const interestGroupName = "%s";
     const hasSignals = %s;
     const reportPostAuctionSignals = %s;
+    const reportRejectReason = %s;
     const postAuctionSignalsPlaceholder = "%s";
     let debugLossReportUrl = "%s";
     let debugWinReportUrl = "%s";
@@ -284,6 +286,10 @@ std::string MakeBidScript(const url::Origin& seller,
       if (debugLossReportUrl) {
         if (reportPostAuctionSignals)
           debugLossReportUrl += postAuctionSignalsPlaceholder;
+        if (reportRejectReason) {
+          debugLossReportUrl += reportPostAuctionSignals ? '&' : '?';
+          debugLossReportUrl += 'rejectReason=${rejectReason}';
+        }
         forDebuggingOnly.reportAdAuctionLoss(debugLossReportUrl);
       }
       if (debugWinReportUrl) {
@@ -387,8 +393,9 @@ std::string MakeBidScript(const url::Origin& seller,
       num_ad_components, interest_group_owner.Serialize().c_str(),
       interest_group_name.c_str(), has_signals ? "true" : "false",
       report_post_auction_signals ? "true" : "false",
-      kPostAuctionSignalsPlaceholder, debug_loss_report_url.c_str(),
-      debug_win_report_url.c_str(), signal_key.c_str(), signal_val.c_str());
+      report_reject_reason ? "true" : "false", kPostAuctionSignalsPlaceholder,
+      debug_loss_report_url.c_str(), debug_win_report_url.c_str(),
+      signal_key.c_str(), signal_val.c_str());
 }
 
 // This can be appended to the standard script to override the function.
@@ -537,8 +544,7 @@ std::string MakeDecisionScript(
       if (reportPostAuctionSignals)
         debugReportUrl += postAuctionSignalsPlaceholder;
       if (reportTopLevelPostAuctionSignals) {
-        if (reportPostAuctionSignals)
-          debugReportUrl += "&";
+        debugReportUrl += reportPostAuctionSignals ? '&' : '?';
         debugReportUrl += topLevelPostAuctionSignalsPlaceholder;
       }
       // Only add key "bid=" to the report URL when report post auction signals
@@ -655,23 +661,13 @@ std::string MakeAuctionScriptNoReportUrl(
     bool report_post_auction_signals = false,
     const std::string& debug_loss_report_url = "",
     const std::string& debug_win_report_url = "") {
-  return MakeDecisionScript(
-      decision_logic_url,
-      /*send_report_url=*/absl::nullopt,
-      /*bid_from_component_auction_wins=*/false,
-      /*report_post_auction_signals=*/report_post_auction_signals,
-      debug_loss_report_url, debug_win_report_url);
+  return MakeDecisionScript(decision_logic_url,
+                            /*send_report_url=*/absl::nullopt,
+                            /*bid_from_component_auction_wins=*/false,
+                            report_post_auction_signals, debug_loss_report_url,
+                            debug_win_report_url);
 }
 
-const char kAuctionScriptRejects2[] = R"(
-  function scoreAd(adMetadata, bid, auctionConfig, browserSignals) {
-    privateAggregation.sendHistogramReport({bucket: 5, value: 6});
-    if (bid === 2)
-      return -1;
-    return bid + 1;
-  }
-)";
-
 const char kBasicReportResult[] = R"(
   function reportResult(auctionConfig, browserSignals) {
     privateAggregation.sendHistogramReport({bucket: 7, value: 8});
@@ -683,8 +679,18 @@ const char kBasicReportResult[] = R"(
   }
 )";
 
-std::string MakeAuctionScriptReject2() {
-  return std::string(kAuctionScriptRejects2) + kBasicReportResult;
+std::string MakeAuctionScriptReject2(
+    const std::string& reject_reason = "not-available") {
+  constexpr char kAuctionScriptRejects2[] = R"(
+    function scoreAd(adMetadata, bid, auctionConfig, browserSignals) {
+      privateAggregation.sendHistogramReport({bucket: 5, value: 6});
+      if (bid === 2)
+        return {desirability: -1, rejectReason: '%s'};
+      return bid + 1;
+    }
+  )";
+  return base::StringPrintf(kAuctionScriptRejects2, reject_reason.c_str()) +
+         kBasicReportResult;
 }
 
 std::string MakeAuctionScriptReject1And2WithDebugReporting(
@@ -695,15 +701,26 @@ std::string MakeAuctionScriptReject1And2WithDebugReporting(
     const debugWinReportUrl = "%s";
     function scoreAd(adMetadata, bid, auctionConfig, browserSignals) {
       let result = bid + 1;
-      if (bid === 1 || bid === 2)
+      let rejectReason = "not-available";
+      if (bid === 1) {
         result = -1;
+        rejectReason = 'invalid-bid';
+      } else if (bid === 2) {
+        result = -1;
+        rejectReason = 'bid-below-auction-floor';
+      }
+
       if (debugLossReportUrl) {
         forDebuggingOnly.reportAdAuctionLoss(
             debugLossReportUrl + '&bid=' + bid);
       }
       if (debugWinReportUrl)
         forDebuggingOnly.reportAdAuctionWin(debugWinReportUrl + "&bid=" + bid);
-      return result;
+      return {
+        desirability: result,
+        allowComponentAuction: true,
+        rejectReason: rejectReason
+      };
     }
   )";
   return base::StringPrintf(kReject1And2WithDebugReporting,
@@ -819,9 +836,11 @@ const GURL ReportWinUrl(
 
 // Returns a report URL with given parameters for forDebuggingOnly win/loss
 // report APIs, with post auction signals included in the URL.
-const GURL DebugReportUrl(const std::string& url,
-                          const PostAuctionSignals& signals,
-                          absl::optional<double> bid = absl::nullopt) {
+const GURL DebugReportUrl(
+    const std::string& url,
+    const PostAuctionSignals& signals,
+    absl::optional<double> bid = absl::nullopt,
+    absl::optional<std::string> reject_reason = absl::nullopt) {
   // Post auction signals needs to be consistent with
   // `kPostAuctionSignalsPlaceholder`. Only keeps integer part of bid values for
   // simplicity for now.
@@ -834,6 +853,11 @@ const GURL DebugReportUrl(const std::string& url,
       signals.made_winning_bid ? "true" : "false",
       signals.highest_scoring_other_bid,
       signals.made_highest_scoring_other_bid ? "true" : "false");
+  if (reject_reason.has_value()) {
+    report_url_string.append(
+        base::StringPrintf("&rejectReason=%s", reject_reason.value().c_str()));
+  }
+
   if (bid.has_value()) {
     return GURL(base::StringPrintf("%s&bid=%.0f", report_url_string.c_str(),
                                    bid.value()));
@@ -5938,6 +5962,8 @@ TEST_F(AuctionRunnerTest, BidderCrashBeforeBidding) {
         std::move(score_ad_params.score_ad_client))
         ->OnScoreAdComplete(
             /*score=*/11,
+            /*reject_reason=*/
+            auction_worklet::mojom::RejectReason::kNotAvailable,
             auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
             /*scoring_signals_data_version=*/0,
             /*has_scoring_signals_data_version=*/false,
@@ -6036,6 +6062,8 @@ TEST_F(AuctionRunnerTest, WinningBidderCrashWhileReporting) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/11,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -6055,6 +6083,8 @@ TEST_F(AuctionRunnerTest, WinningBidderCrashWhileReporting) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/10,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -6131,8 +6161,7 @@ TEST_F(AuctionRunnerTest, ForDebuggingOnlyReporting) {
                     kBidder2DebugLossReportUrl, kBidder2DebugWinReportUrl));
   auction_worklet::AddJavascriptResponse(
       &url_loader_factory_, kSellerUrl,
-      MakeAuctionScript(/*report_post_auction_signals=*/false,
-                        GURL("https://adstuff.publisher1.com/auction.js"),
+      MakeAuctionScript(/*report_post_auction_signals=*/false, kSellerUrl,
                         kSellerDebugLossReportBaseUrl,
                         kSellerDebugWinReportBaseUrl));
 
@@ -6202,6 +6231,8 @@ TEST_F(AuctionRunnerTest, SellerCrash) {
           std::move(score_ad_params.score_ad_client))
           ->OnScoreAdComplete(
               /*score=*/10,
+              /*reject_reason=*/
+              auction_worklet::mojom::RejectReason::kNotAvailable,
               auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
               /*scoring_signals_data_version=*/0,
               /*has_scoring_signals_data_version=*/false,
@@ -6216,6 +6247,8 @@ TEST_F(AuctionRunnerTest, SellerCrash) {
           std::move(score_ad_params2.score_ad_client))
           ->OnScoreAdComplete(
               /*score=*/11,
+              /*reject_reason=*/
+              auction_worklet::mojom::RejectReason::kNotAvailable,
               auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
               /*scoring_signals_data_version=*/0,
               /*has_scoring_signals_data_version=*/false,
@@ -6330,6 +6363,8 @@ TEST_F(AuctionRunnerTest, ComponentAuctionOneBidderCrashesBeforeBidding) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/3,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParams::New(
               /*ad=*/"null",
               /*bid=*/0,
@@ -6351,6 +6386,8 @@ TEST_F(AuctionRunnerTest, ComponentAuctionOneBidderCrashesBeforeBidding) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/4,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -6449,6 +6486,8 @@ TEST_F(AuctionRunnerTest, ComponentAuctionComponentSellersReportResultFails) {
         std::move(score_ad_params.score_ad_client))
         ->OnScoreAdComplete(
             /*score=*/3,
+            /*reject_reason=*/
+            auction_worklet::mojom::RejectReason::kNotAvailable,
             auction_worklet::mojom::ComponentAuctionModifiedBidParams::New(
                 /*ad=*/"null",
                 /*bid=*/0,
@@ -6470,6 +6509,8 @@ TEST_F(AuctionRunnerTest, ComponentAuctionComponentSellersReportResultFails) {
         std::move(score_ad_params.score_ad_client))
         ->OnScoreAdComplete(
             /*score=*/4,
+            /*reject_reason=*/
+            auction_worklet::mojom::RejectReason::kNotAvailable,
             auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
             /*scoring_signals_data_version=*/0,
             /*has_scoring_signals_data_version=*/false,
@@ -6676,7 +6717,10 @@ TEST_F(AuctionRunnerTest, ComponentAuctionComponentSellerBadBidParams) {
     EXPECT_EQ(2, score_ad_params.bid);
     mojo::Remote<auction_worklet::mojom::ScoreAdClient>(
         std::move(score_ad_params.score_ad_client))
-        ->OnScoreAdComplete(/*score=*/3, test_case.params.Clone(),
+        ->OnScoreAdComplete(/*score=*/3,
+                            /*reject_reason=*/
+                            auction_worklet::mojom::RejectReason::kNotAvailable,
+                            test_case.params.Clone(),
                             /*scoring_signals_data_version=*/0,
                             /*has_scoring_signals_data_version=*/false,
                             /*debug_loss_report_url=*/absl::nullopt,
@@ -6735,6 +6779,8 @@ TEST_F(AuctionRunnerTest, TopLevelSellerBadBidParams) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/3,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParams::New(
               /*ad=*/"null",
               /*bid=*/0,
@@ -6805,6 +6851,8 @@ TEST_F(AuctionRunnerTest, NullAdComponents) {
           std::move(score_ad_params.score_ad_client))
           ->OnScoreAdComplete(
               /*score=*/11,
+              /*reject_reason=*/
+              auction_worklet::mojom::RejectReason::kNotAvailable,
               auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
               /*scoring_signals_data_version=*/0,
               /*has_scoring_signals_data_version=*/false,
@@ -6902,6 +6950,8 @@ TEST_F(AuctionRunnerTest, AdComponentsLimit) {
           std::move(score_ad_params.score_ad_client))
           ->OnScoreAdComplete(
               /*score=*/11,
+              /*reject_reason=*/
+              auction_worklet::mojom::RejectReason::kNotAvailable,
               auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
               /*scoring_signals_data_version=*/0,
               /*has_scoring_signals_data_version=*/false,
@@ -7139,6 +7189,8 @@ TEST_F(AuctionRunnerTest, BadSellerReportUrl) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/10,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -7198,6 +7250,8 @@ TEST_F(AuctionRunnerTest, BadSellerBeaconUrl) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/10,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -7267,6 +7321,8 @@ TEST_F(AuctionRunnerTest, BadComponentSellerReportUrl) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/10,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParams::New(
               /*ad=*/"null",
               /*bid=*/0,
@@ -7285,6 +7341,8 @@ TEST_F(AuctionRunnerTest, BadComponentSellerReportUrl) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/10,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -7354,6 +7412,8 @@ TEST_F(AuctionRunnerTest, BadBidderReportUrl) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/10,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -7417,6 +7477,8 @@ TEST_F(AuctionRunnerTest, BadBidderBeaconUrl) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/10,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -7485,6 +7547,8 @@ TEST_F(AuctionRunnerTest, DestroyBidderWorkletWithoutBid) {
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/11,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -7550,6 +7614,8 @@ TEST_F(AuctionRunnerTest, Tie) {
         std::move(score_ad_params.score_ad_client))
         ->OnScoreAdComplete(
             /*score=*/10,
+            /*reject_reason=*/
+            auction_worklet::mojom::RejectReason::kNotAvailable,
             auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
             /*scoring_signals_data_version=*/0,
             /*has_scoring_signals_data_version=*/false,
@@ -7567,6 +7633,8 @@ TEST_F(AuctionRunnerTest, Tie) {
         std::move(score_ad_params.score_ad_client))
         ->OnScoreAdComplete(
             /*score=*/10,
+            /*reject_reason=*/
+            auction_worklet::mojom::RejectReason::kNotAvailable,
             auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
             /*scoring_signals_data_version=*/0,
             /*has_scoring_signals_data_version=*/false,
@@ -7701,6 +7769,8 @@ TEST_F(AuctionRunnerTest, WorkletOrder) {
                 std::move(score_ad_params1.score_ad_client))
                 ->OnScoreAdComplete(
                     /*score=*/bidder1_wins ? 11 : 9,
+                    /*reject_reason=*/
+                    auction_worklet::mojom::RejectReason::kNotAvailable,
                     auction_worklet::mojom::
                         ComponentAuctionModifiedBidParamsPtr(),
                     /*scoring_signals_data_version=*/0,
@@ -7714,15 +7784,18 @@ TEST_F(AuctionRunnerTest, WorkletOrder) {
           case Event::kBid2Scored:
             mojo::Remote<auction_worklet::mojom::ScoreAdClient>(
                 std::move(score_ad_params2.score_ad_client))
-                ->OnScoreAdComplete(/*score=*/10,
-                                    auction_worklet::mojom::
-                                        ComponentAuctionModifiedBidParamsPtr(),
-                                    /*scoring_signals_data_version=*/0,
-                                    /*has_scoring_signals_data_version=*/false,
-                                    /*debug_loss_report_url=*/absl::nullopt,
-                                    /*debug_win_report_url=*/absl::nullopt,
-                                    /*pa_requests=*/{},
-                                    /*errors=*/{});
+                ->OnScoreAdComplete(
+                    /*score=*/10,
+                    /*reject_reason=*/
+                    auction_worklet::mojom::RejectReason::kNotAvailable,
+                    auction_worklet::mojom::
+                        ComponentAuctionModifiedBidParamsPtr(),
+                    /*scoring_signals_data_version=*/0,
+                    /*has_scoring_signals_data_version=*/false,
+                    /*debug_loss_report_url=*/absl::nullopt,
+                    /*debug_win_report_url=*/absl::nullopt,
+                    /*pa_requests=*/{},
+                    /*errors=*/{});
             // Wait for the AuctionRunner to receive the score.
             task_environment_.RunUntilIdle();
             break;
@@ -9546,14 +9619,16 @@ TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
                     kBidder1, kBidder1Name,
                     /*has_signals=*/false, "k1", "a",
                     /*report_post_auction_signals=*/true,
-                    kBidder1DebugLossReportUrl, kBidder1DebugWinReportUrl));
+                    kBidder1DebugLossReportUrl, kBidder1DebugWinReportUrl,
+                    /*report_reject_reason=*/true));
   auction_worklet::AddJavascriptResponse(
       &url_loader_factory_, kBidder2Url,
       MakeBidScript(kSeller, "2", "https://ad2.com/", /*num_ad_components=*/2,
                     kBidder2, kBidder2Name,
                     /*has_signals=*/false, "l2", "b",
                     /*report_post_auction_signals=*/true,
-                    kBidder2DebugLossReportUrl, kBidder2DebugWinReportUrl));
+                    kBidder2DebugLossReportUrl, kBidder2DebugWinReportUrl,
+                    /*report_reject_reason=*/true));
   auction_worklet::AddJavascriptResponse(
       &url_loader_factory_, kSellerUrl,
       MakeAuctionScriptReject1And2WithDebugReporting(
@@ -9571,8 +9646,10 @@ TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
   EXPECT_THAT(
       res.debug_loss_report_urls,
       testing::UnorderedElementsAre(
-          DebugReportUrl(kBidder1DebugLossReportUrl, PostAuctionSignals()),
-          DebugReportUrl(kBidder2DebugLossReportUrl, PostAuctionSignals()),
+          DebugReportUrl(kBidder1DebugLossReportUrl, PostAuctionSignals(),
+                         /*bid=*/absl::nullopt, "invalid-bid"),
+          DebugReportUrl(kBidder2DebugLossReportUrl, PostAuctionSignals(),
+                         /*bid=*/absl::nullopt, "bid-below-auction-floor"),
           DebugReportUrl(kSellerDebugLossReportBaseUrl, PostAuctionSignals(),
                          /*bid=*/1),
           DebugReportUrl(kSellerDebugLossReportBaseUrl, PostAuctionSignals(),
@@ -9706,7 +9783,10 @@ TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
                          /*bid=*/2)));
 }
 
-// Like above test, but top-level seller rejects all bidders.
+// Test debug loss reporting in an auction with no winner. Component bidder 1 is
+// rejected by component seller, and component bidder 2 is rejected by top-level
+// seller. Component bidders get component auction's reject reason but not the
+// top-level auction's.
 TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
        ForDebuggingOnlyReportingComponentAuctionNoWinner) {
   interest_group_buyers_.emplace();
@@ -9715,21 +9795,17 @@ TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
       CreateAuctionConfig(kComponentSeller1Url, {{kBidder1}}));
   auction_worklet::AddJavascriptResponse(
       &url_loader_factory_, kComponentSeller1Url,
-      MakeDecisionScript(
-          kComponentSeller1Url,
-          /*send_report_url=*/GURL("https://component1-report.test/"),
-          /*bid_from_component_auction_wins=*/false,
-          /*report_post_auction_signals=*/true,
-          /*debug_loss_report_url=*/"https://component1-loss-reporting.test/",
-          /*debug_win_report_url=*/"https://component1-win-reporting.test/",
-          /*report_top_level_post_auction_signals*/ true));
+      MakeAuctionScriptReject1And2WithDebugReporting(
+          "https://component1-loss-reporting.test/?",
+          "https://component1-win-reporting.test/?"));
   auction_worklet::AddJavascriptResponse(
       &url_loader_factory_, kBidder1Url,
       MakeBidScript(kComponentSeller1, "1", "https://ad1.com/",
                     /*num_ad_components=*/2, kBidder1, kBidder1Name,
                     /*has_signals=*/true, "k1", "a",
                     /*report_post_auction_signals=*/true,
-                    kBidder1DebugLossReportUrl, kBidder1DebugWinReportUrl));
+                    kBidder1DebugLossReportUrl, kBidder1DebugWinReportUrl,
+                    /*report_reject_reason=*/true));
   auction_worklet::AddBidderJsonResponse(
       &url_loader_factory_,
       GURL(kBidder1TrustedSignalsUrl.spec() +
@@ -9755,7 +9831,8 @@ TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
                     /*num_ad_components=*/2, kBidder2, kBidder2Name,
                     /*has_signals=*/true, "l2", "b",
                     /*report_post_auction_signals=*/true,
-                    kBidder2DebugLossReportUrl, kBidder2DebugWinReportUrl));
+                    kBidder2DebugLossReportUrl, kBidder2DebugWinReportUrl,
+                    /*report_reject_reason=*/true));
   auction_worklet::AddBidderJsonResponse(
       &url_loader_factory_,
       GURL(kBidder2TrustedSignalsUrl.spec() +
@@ -9775,7 +9852,11 @@ function scoreAd(adMetadata, bid, auctionConfig, trustedScoringSignals,
   // While not setting `allowComponentAuction` will also reject the ad, it
   // also prevents loss reports and adds an error message, so need to set
   // it to true.
-  return {desirability: 0, allowComponentAuction: true};
+  return {
+    desirability: 0,
+    allowComponentAuction: true,
+    rejectReason: "bid-below-auction-floor"
+  };
 }
   )",
                          kPostAuctionSignalsPlaceholder,
@@ -9787,34 +9868,27 @@ function scoreAd(adMetadata, bid, auctionConfig, trustedScoringSignals,
   // No interest group won the auction.
   EXPECT_FALSE(result_.ad_url);
 
+  // Component bidder 1 rejected by component auction gets its reject reason
+  // "invalid-bid". Component bidders don't get the top-level auction's reject
+  // reason.
   EXPECT_THAT(
       result_.debug_loss_report_urls,
       testing::UnorderedElementsAre(
           DebugReportUrl(kBidder1DebugLossReportUrl,
                          PostAuctionSignals(
-                             /*winning_bid=*/1,
-                             /*made_winning_bid=*/true,
+                             /*winning_bid=*/0,
+                             /*made_winning_bid=*/false,
                              /*highest_scoring_other_bid=*/0,
-                             /*made_highest_scoring_other_bid=*/false)),
-          ComponentSellerDebugReportUrl(
-              "https://component1-loss-reporting.test/",
-              /*signals=*/
-              PostAuctionSignals(/*winning_bid=*/1,
-                                 /*made_winning_bid=*/true,
-                                 /*highest_scoring_other_bid=*/0,
-                                 /*made_highest_scoring_other_bid=*/false),
-              /*top_level_signals=*/
-              PostAuctionSignals(),
-              /*bid=*/1),
-          DebugReportUrl("https://top-seller-loss-reporting.test/",
-                         PostAuctionSignals(),
-                         /*bid=*/1),
+                             /*made_highest_scoring_other_bid=*/false),
+                         /*bid=*/absl::nullopt, "invalid-bid"),
+          GURL("https://component1-loss-reporting.test/?&bid=1"),
           DebugReportUrl(kBidder2DebugLossReportUrl,
                          PostAuctionSignals(
                              /*winning_bid=*/2,
                              /*made_winning_bid=*/true,
                              /*highest_scoring_other_bid=*/0,
-                             /*made_highest_scoring_other_bid=*/false)),
+                             /*made_highest_scoring_other_bid=*/false),
+                         /*bid=*/absl::nullopt, "not-available"),
           ComponentSellerDebugReportUrl(
               "https://component2-loss-reporting.test/",
               /*signals=*/
@@ -10097,6 +10171,8 @@ TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
         std::move(score_ad_params.score_ad_client))
         ->OnScoreAdComplete(
             /*score=*/10,
+            /*reject_reason=*/
+            auction_worklet::mojom::RejectReason::kNotAvailable,
             auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
             /*scoring_signals_data_version=*/0,
             /*has_scoring_signals_data_version=*/false,
@@ -10160,6 +10236,8 @@ TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
       std::move(score_ad_params.score_ad_client))
       ->OnScoreAdComplete(
           /*score=*/10,
+          /*reject_reason=*/
+          auction_worklet::mojom::RejectReason::kNotAvailable,
           auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr(),
           /*scoring_signals_data_version=*/0,
           /*has_scoring_signals_data_version=*/false,
@@ -10343,8 +10421,231 @@ TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
                                     GURL("https://seller0.test/win/11")));
 }
 
-// Enable and test forDebuggingOnly.reportAdAuctionLoss() and
-// forDebuggingOnly.reportAdAuctionWin() APIs.
+// Reject reason returned by scoreAd() for a rejected bid can be reported to the
+// bidder through its debug loss report URL.
+TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
+       RejectedBidGetsRejectReason) {
+  for (const std::string& reject_reason :
+       {"not-available", "invalid-bid", "bid-below-auction-floor",
+        "pending-approval-by-exchange", "disapproved-by-exchange",
+        "blocked-by-publisher", "language-exclusions", "category-exclusions"}) {
+    auction_worklet::AddJavascriptResponse(
+        &url_loader_factory_, kBidder1Url,
+        MakeBidScript(kSeller, "1", "https://ad1.com/", /*num_ad_components=*/2,
+                      kBidder1, kBidder1Name,
+                      /*has_signals=*/false, "k1", "a",
+                      /*report_post_auction_signals=*/false,
+                      kBidder1DebugLossReportUrl, kBidder1DebugWinReportUrl,
+                      /*report_reject_reason=*/true));
+    // Bidder 2 will get a negative score from scoreAd().
+    auction_worklet::AddJavascriptResponse(
+        &url_loader_factory_, kBidder2Url,
+        MakeBidScript(kSeller, "2", "https://ad2.com/", /*num_ad_components=*/2,
+                      kBidder2, kBidder2Name,
+                      /*has_signals=*/false, "l2", "b",
+                      /*report_post_auction_signals=*/false,
+                      kBidder2DebugLossReportUrl, kBidder2DebugWinReportUrl,
+                      /*report_reject_reason=*/true));
+    auction_worklet::AddJavascriptResponse(
+        &url_loader_factory_, kSellerUrl,
+        MakeAuctionScriptReject2(reject_reason));
+
+    const Result& res = RunStandardAuction();
+    // Bidder 1 won the auction.
+    EXPECT_EQ(InterestGroupKey(kBidder1, kBidder1Name),
+              result_.winning_group_id);
+    EXPECT_EQ(GURL("https://ad1.com/"), res.ad_url);
+
+    EXPECT_EQ(1u, res.debug_loss_report_urls.size());
+    // Seller rejected bidder 2 and returned the reject reason which were then
+    // reported to bidder 2 through its loss report URL.
+    EXPECT_THAT(res.debug_loss_report_urls,
+                testing::UnorderedElementsAre(base::StringPrintf(
+                    "https://bidder2-debug-loss-reporting.com/"
+                    "?rejectReason=%s",
+                    reject_reason.c_str())));
+
+    EXPECT_EQ(1u, res.debug_win_report_urls.size());
+    EXPECT_THAT(res.debug_win_report_urls,
+                testing::UnorderedElementsAre(kBidder1DebugWinReportUrl));
+  }
+}
+
+// Reject reason returned by scoreAd() for a bid whose score is positive is
+// ignored and will not be reported to the bidder.
+TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
+       rejectReasonIgnoredForPositiveBid) {
+  auction_worklet::AddJavascriptResponse(
+      &url_loader_factory_, kBidder1Url,
+      MakeBidScript(kSeller, "1", "https://ad1.com/", /*num_ad_components=*/2,
+                    kBidder1, kBidder1Name,
+                    /*has_signals=*/false, "k1", "a",
+                    /*report_post_auction_signals=*/false,
+                    kBidder1DebugLossReportUrl, kBidder1DebugWinReportUrl,
+                    /*report_reject_reason=*/true));
+
+  auction_worklet::AddJavascriptResponse(
+      &url_loader_factory_, kBidder2Url,
+      MakeBidScript(kSeller, "3", "https://ad2.com/", /*num_ad_components=*/2,
+                    kBidder2, kBidder2Name,
+                    /*has_signals=*/false, "l2", "b",
+                    /*report_post_auction_signals=*/false,
+                    kBidder2DebugLossReportUrl, kBidder2DebugWinReportUrl,
+                    /*report_reject_reason=*/true));
+  auction_worklet::AddJavascriptResponse(&url_loader_factory_, kSellerUrl,
+                                         MakeAuctionScriptReject2());
+
+  const Result& res = RunStandardAuction();
+  // Bidder 2 won the auction.
+  EXPECT_EQ(InterestGroupKey(kBidder2, kBidder2Name), result_.winning_group_id);
+  EXPECT_EQ(GURL("https://ad2.com/"), res.ad_url);
+
+  EXPECT_EQ(1u, res.debug_loss_report_urls.size());
+  // Reject reason returned by scoreAd() for bidder 1 should be ignored and
+  // reported as "not-available" in debug loss report URL, because the bid gets
+  // a positive score thus not rejected by seller.
+  EXPECT_THAT(
+      res.debug_loss_report_urls,
+      testing::UnorderedElementsAre("https://bidder1-debug-loss-reporting.com/"
+                                    "?rejectReason=not-available"));
+
+  EXPECT_EQ(1u, res.debug_win_report_urls.size());
+  EXPECT_THAT(res.debug_win_report_urls,
+              testing::UnorderedElementsAre(kBidder2DebugWinReportUrl));
+}
+
+// Only bidders' debug loss report URLs support macro ${rejectReason}.
+// Bidders' debug win report URLs and sellers' debug loss/win report URLs does
+// not.
+TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
+       rejectReasonInBidderDebugLossReportOnly) {
+  const char kBidder1Script[] = R"(
+    function generateBid(interestGroup, auctionSignals, perBuyerSignals,
+                         trustedBiddingSignals, browserSignals) {
+      forDebuggingOnly.reportAdAuctionLoss(
+          'https://bidder1-debug-loss-reporting.com/?reason=${rejectReason}');
+      forDebuggingOnly.reportAdAuctionWin(
+          'https://bidder1-debug-win-reporting.com/?reason=${rejectReason}');
+      return {
+        bid: 1,
+        render: interestGroup.ads[0].renderUrl
+      };
+    }
+
+    // Prevent an error about this method not existing.
+    function reportWin() {}
+  )";
+
+  const char kBidder2Script[] = R"(
+    function generateBid(interestGroup, auctionSignals, perBuyerSignals,
+                         trustedBiddingSignals, browserSignals) {
+      forDebuggingOnly.reportAdAuctionLoss(
+          'https://bidder2-debug-loss-reporting.com/?reason=${rejectReason}');
+      forDebuggingOnly.reportAdAuctionWin(
+          'https://bidder2-debug-win-reporting.com/?reason=${rejectReason}');
+      return {
+        bid: 2,
+        render: interestGroup.ads[0].renderUrl
+      };
+    }
+
+    // Prevent an error about this method not existing.
+    function reportWin() {}
+  )";
+
+  // Desirability is -1 if bid is 1, otherwise is bid.
+  const char kSellerScript[] = R"(
+    function scoreAd(adMetadata, bid, auctionConfig, trustedScoringSignals,
+                     browserSignals) {
+      forDebuggingOnly.reportAdAuctionLoss(
+          'https://seller-debug-loss-reporting.com/?reason=${rejectReason}');
+      forDebuggingOnly.reportAdAuctionWin(
+          'https://seller-debug-win-reporting.com/?reason=${rejectReason}');
+      if (bid == 1) {
+        return {desirability: -1, rejectReason: 'invalid-bid'}
+      } else {
+        return bid;
+      }
+    }
+
+    // Prevent an error about this method not existing.
+    function reportResult() {}
+  )";
+
+  auction_worklet::AddJavascriptResponse(&url_loader_factory_, kBidder1Url,
+                                         kBidder1Script);
+  auction_worklet::AddJavascriptResponse(&url_loader_factory_, kBidder2Url,
+                                         kBidder2Script);
+  auction_worklet::AddJavascriptResponse(&url_loader_factory_, kSellerUrl,
+                                         kSellerScript);
+
+  const Result& res = RunStandardAuction();
+  // Bidder 2 won the auction.
+  EXPECT_EQ(InterestGroupKey(kBidder2, kBidder2Name), result_.winning_group_id);
+  EXPECT_EQ(GURL("https://ad2.com/"), res.ad_url);
+
+  // Only bidder's debug loss report supports macro ${rejectReason}.
+  EXPECT_EQ(2u, res.debug_loss_report_urls.size());
+  EXPECT_THAT(
+      res.debug_loss_report_urls,
+      testing::UnorderedElementsAre(
+          "https://bidder1-debug-loss-reporting.com/?reason=invalid-bid",
+          "https://seller-debug-loss-reporting.com/"
+          "?reason=${rejectReason}"));
+  EXPECT_EQ(2u, res.debug_win_report_urls.size());
+  EXPECT_THAT(
+      res.debug_win_report_urls,
+      testing::UnorderedElementsAre("https://bidder2-debug-win-reporting.com/"
+                                    "?reason=${rejectReason}",
+                                    "https://seller-debug-win-reporting.com/"
+                                    "?reason=${rejectReason}"));
+}
+
+// When scoreAd() does not return a reject reason, report it as "not-available"
+// in bidder's loss report URL as default.
+TEST_F(AuctionRunnerBiddingAndScoringDebugReportingAPIEnabledTest,
+       SellerNotReturningRejectReason) {
+  const char kBidderScript[] = R"(
+    function generateBid(interestGroup, auctionSignals, perBuyerSignals,
+                         trustedBiddingSignals, browserSignals) {
+      forDebuggingOnly.reportAdAuctionLoss(
+          'https://bidder-debug-loss-reporting.com/?reason=${rejectReason}');
+      return {
+        bid: 1,
+        render: interestGroup.ads[0].renderUrl
+      };
+    }
+
+    // Prevent an error about this method not existing.
+    function reportWin() {}
+  )";
+
+  const char kSellerScript[] = R"(
+    function scoreAd(adMetadata, bid, auctionConfig, trustedScoringSignals,
+                     browserSignals) {
+      return {desirability: -1};
+    }
+
+    // Prevent an error about this method not existing.
+    function reportResult() {}
+  )";
+
+  auction_worklet::AddJavascriptResponse(&url_loader_factory_, kBidder1Url,
+                                         kBidderScript);
+  auction_worklet::AddJavascriptResponse(&url_loader_factory_, kSellerUrl,
+                                         kSellerScript);
+
+  const Result& res = RunStandardAuction();
+
+  EXPECT_EQ(1u, res.debug_loss_report_urls.size());
+  EXPECT_THAT(
+      res.debug_loss_report_urls,
+      testing::UnorderedElementsAre("https://bidder-debug-loss-reporting.com/"
+                                    "?reason=not-available"));
+  EXPECT_EQ(0u, res.debug_win_report_urls.size());
+}
+
+// Disable private aggregation API.
 class AuctionRunnerPrivateAggregationAPIDisabledTest
     : public AuctionRunnerTest {
  public:

content/browser/interest_group/interest_group_auction.cc

@@ -410,13 +410,15 @@ class InterestGroupAuction::BuyerHelper
         continue;
       }
       if (bid_state->bidder_debug_loss_report_url.has_value()) {
-        // Losing bidders should not get highest_scoring_other_bid and
-        // made_highest_scoring_other_bid signals.
+        // Losing and rejected bidders should not get highest_scoring_other_bid
+        // and made_highest_scoring_other_bid signals.
         debug_loss_report_urls.emplace_back(FillPostAuctionSignals(
             std::move(bid_state->bidder_debug_loss_report_url).value(),
             PostAuctionSignals(signals.winning_bid, signals.made_winning_bid,
-                               0.0, false)));
+                               0.0, false),
+            /*top_level_signals=*/absl::nullopt, bid_state->reject_reason));
       }
+      // TODO(qingxinwu): Add reject reason to seller debug loss report as well.
       if (bid_state->seller_debug_loss_report_url.has_value()) {
         debug_loss_report_urls.emplace_back(FillPostAuctionSignals(
             std::move(bid_state->seller_debug_loss_report_url).value(), signals,
@@ -762,10 +764,10 @@ class InterestGroupAuction::BuyerHelper
                            maybe_bidding_signals_data_version,
                            debug_loss_report_url, debug_win_report_url);
       if (bid)
-        state->bidder_debug_loss_report_url = std::move(debug_loss_report_url);
+        state->bidder_debug_loss_report_url = debug_loss_report_url;
     } else {
       // Bidders who do not bid are allowed to get loss report.
-      state->bidder_debug_loss_report_url = std::move(debug_loss_report_url);
+      state->bidder_debug_loss_report_url = debug_loss_report_url;
     }
 
     // Release the worklet. If it wins the auction, it will be requested again
@@ -775,7 +777,7 @@ class InterestGroupAuction::BuyerHelper
     if (!bid) {
       state->EndTracing();
     } else {
-      state->bidder_debug_win_report_url = std::move(debug_win_report_url);
+      state->bidder_debug_win_report_url = debug_win_report_url;
       state->made_bid = true;
       auction_->ScoreBidIfReady(std::move(bid));
     }
@@ -1180,10 +1182,43 @@ void InterestGroupAuction::GetInterestGroupsThatBid(
   }
 }
 
+base::StringPiece GetRejectReasonString(
+    const auction_worklet::mojom::RejectReason reject_reason) {
+  base::StringPiece reject_reason_str;
+  switch (reject_reason) {
+    case auction_worklet::mojom::RejectReason::kNotAvailable:
+      reject_reason_str = "not-available";
+      break;
+    case auction_worklet::mojom::RejectReason::kInvalidBid:
+      reject_reason_str = "invalid-bid";
+      break;
+    case auction_worklet::mojom::RejectReason::kBidBelowAuctionFloor:
+      reject_reason_str = "bid-below-auction-floor";
+      break;
+    case auction_worklet::mojom::RejectReason::kPendingApprovalByExchange:
+      reject_reason_str = "pending-approval-by-exchange";
+      break;
+    case auction_worklet::mojom::RejectReason::kDisapprovedByExchange:
+      reject_reason_str = "disapproved-by-exchange";
+      break;
+    case auction_worklet::mojom::RejectReason::kBlockedByPublisher:
+      reject_reason_str = "blocked-by-publisher";
+      break;
+    case auction_worklet::mojom::RejectReason::kLanguageExclusions:
+      reject_reason_str = "language-exclusions";
+      break;
+    case auction_worklet::mojom::RejectReason::kCategoryExclusions:
+      reject_reason_str = "category-exclusions";
+      break;
+  }
+  return reject_reason_str;
+}
+
 GURL InterestGroupAuction::FillPostAuctionSignals(
     const GURL& url,
     const PostAuctionSignals& signals,
-    const absl::optional<PostAuctionSignals>& top_level_signals) {
+    const absl::optional<PostAuctionSignals>& top_level_signals,
+    const absl::optional<auction_worklet::mojom::RejectReason> reject_reason) {
   // TODO(qingxinwu): Round `winning_bid` and `highest_scoring_other_bid` to two
   // most-significant digits. Maybe same to corresponding browser signals of
   // reportWin()/reportResult().
@@ -1217,6 +1252,12 @@ GURL InterestGroupAuction::FillPostAuctionSignals(
         top_level_signals->made_winning_bid ? "true" : "false");
   }
 
+  if (reject_reason.has_value()) {
+    base::ReplaceSubstringsAfterOffset(
+        &query_string, 0, "${rejectReason}",
+        GetRejectReasonString(reject_reason.value()));
+  }
+
   GURL::Replacements replacements;
   replacements.SetQueryStr(query_string);
   return url.ReplaceComponents(replacements);
@@ -1671,6 +1712,7 @@ bool InterestGroupAuction::ValidateScoreBidCompleteResult(
 
 void InterestGroupAuction::OnScoreAdComplete(
     double score,
+    auction_worklet::mojom::RejectReason reject_reason,
     auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr
         component_auction_modified_bid_params,
     uint32_t data_version,
@@ -1719,6 +1761,9 @@ void InterestGroupAuction::OnScoreAdComplete(
         std::move(debug_loss_report_url);
     bid->bid_state->seller_debug_win_report_url =
         std::move(debug_win_report_url);
+    // Ignores reject reason if score > 0.
+    if (score <= 0)
+      bid->bid_state->reject_reason = reject_reason;
   } else {
     bid->bid_state->top_level_seller_debug_loss_report_url =
         std::move(debug_loss_report_url);

content/browser/interest_group/interest_group_auction.h

@@ -243,6 +243,11 @@ class CONTENT_EXPORT InterestGroupAuction
     // auction, won it, and was then scored by the top-level seller.
     absl::optional<GURL> top_level_seller_debug_win_report_url;
     absl::optional<GURL> top_level_seller_debug_loss_report_url;
+
+    // The reason this bid was rejected by the auction (i.e., reason why score
+    // was non-positive).
+    auction_worklet::mojom::RejectReason reject_reason =
+        auction_worklet::mojom::RejectReason::kNotAvailable;
   };
 
   // Result of generated a bid. Contains information that needs to score a bid
@@ -541,6 +546,7 @@ class CONTENT_EXPORT InterestGroupAuction
   // auction_worklet::mojom::ScoreAdClient implementation:
   void OnScoreAdComplete(
       double score,
+      auction_worklet::mojom::RejectReason reject_reason,
       auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr
           component_auction_modified_bid_params,
       uint32_t scoring_signals_data_version,
@@ -638,10 +644,13 @@ class CONTENT_EXPORT InterestGroupAuction
   // Replaces `${}` placeholders in a debug report URL's query string for post
   // auction signals if exist. Only replaces unescaped placeholder ${}, but
   // not escaped placeholder (i.e., %24%7B%7D).
-  static GURL FillPostAuctionSignals(const GURL& url,
-                                     const PostAuctionSignals& signals,
-                                     const absl::optional<PostAuctionSignals>&
-                                         top_level_signals = absl::nullopt);
+  static GURL FillPostAuctionSignals(
+      const GURL& url,
+      const PostAuctionSignals& signals,
+      const absl::optional<PostAuctionSignals>& top_level_signals =
+          absl::nullopt,
+      const absl::optional<auction_worklet::mojom::RejectReason> reject_reason =
+          absl::nullopt);
 
   // Tracing ID associated with the Auction. A nestable
   // async "Auction" trace

content/services/auction_worklet/public/mojom/seller_worklet.mojom

@@ -54,6 +54,18 @@ struct ComponentAuctionReportResultParams {
   bool has_modified_bid;
 };
 
+// The reason a bid was rejected by an auction.
+enum RejectReason {
+  kNotAvailable = 0,
+  kInvalidBid = 1,
+  kBidBelowAuctionFloor = 2,
+  kPendingApprovalByExchange = 3,
+  kDisapprovedByExchange = 4,
+  kBlockedByPublisher = 5,
+  kLanguageExclusions = 6,
+  kCategoryExclusions = 7,
+};
+
 // Interface for returning ScoreAd results. The advantage of having an interface
 // is that it makes ScoreAd() calls cancellable, and allows callbacks passed
 // over the Mojo pipe to be deleted when the Mojo pipe is, to avoid setting off
@@ -66,6 +78,10 @@ interface ScoreAdClient {
   //  of 0 indicates either an error running the script, or that the script
   //  indicated the bid should not be used.
   //
+  // `reject_reason` The reason this bid was rejected by the auction (i.e., the
+  //  reason why `score` was non-positive). Default to kNotAvailable if not set.
+  //  Will be ignored if `score` is positive.
+  //
   // `component_auction_modified_bid_params` If this is a component seller
   //  worklet, contains parameters to pass to the top-level seller worklet
   //  in place of values from the original bidder worklet's BidderWorkletBid.
@@ -96,6 +112,7 @@ interface ScoreAdClient {
   //  empty if `score` is positive, nor should it be assumed to be non-empty if
   //  `score` is 0.
   OnScoreAdComplete(double score,
+                    RejectReason reject_reason,
                     ComponentAuctionModifiedBidParams?
                         component_auction_modified_bid_params,
                     uint32 scoring_signals_data_version,
@@ -160,7 +177,7 @@ interface SellerWorklet {
   //  to use with tracing calls.
   //
   // `score_ad_client` When the ScoreAd completes, successfully or not, its
-  // OnScoreAdComplete() method will invoked be invoked with the results.
+  // OnScoreAdComplete() method will be invoked with the results.
   ScoreAd(string ad_metadata_json,
           double bid,
           blink.mojom.AuctionAdConfigNonSharedParams

content/services/auction_worklet/seller_worklet.cc

@@ -6,6 +6,7 @@
 
 #include <stdint.h>
 
+#include <cmath>
 #include <list>
 #include <memory>
 #include <string>
@@ -261,6 +262,30 @@ bool AddOtherSeller(
       browser_signals_other_seller->get_component_seller().Serialize());
 }
 
+// Converts reject reason string to corresponding mojom enum.
+absl::optional<mojom::RejectReason> RejectReasonStringToEnum(
+    const std::string& reason) {
+  if (reason == "not-available") {
+    return mojom::RejectReason::kNotAvailable;
+  } else if (reason == "invalid-bid") {
+    return mojom::RejectReason::kInvalidBid;
+  } else if (reason == "bid-below-auction-floor") {
+    return mojom::RejectReason::kBidBelowAuctionFloor;
+  } else if (reason == "pending-approval-by-exchange") {
+    return mojom::RejectReason::kPendingApprovalByExchange;
+  } else if (reason == "disapproved-by-exchange") {
+    return mojom::RejectReason::kDisapprovedByExchange;
+  } else if (reason == "blocked-by-publisher") {
+    return mojom::RejectReason::kBlockedByPublisher;
+  } else if (reason == "language-exclusions") {
+    return mojom::RejectReason::kLanguageExclusions;
+  } else if (reason == "category-exclusions") {
+    return mojom::RejectReason::kCategoryExclusions;
+  }
+  // Invalid (out of range) reject reason.
+  return absl::nullopt;
+}
+
 }  // namespace
 
 SellerWorklet::SellerWorklet(
@@ -595,6 +620,7 @@ void SellerWorklet::V8State::ScoreAd(
     // `scoreAd()` might use them to detect script timeout or failures.
     PostScoreAdCallbackToUserThread(
         std::move(callback), /*score=*/0,
+        /*reject_reason=*/mojom::RejectReason::kNotAvailable,
         /*component_auction_modified_bid_params=*/nullptr,
         /*scoring_signals_data_version=*/absl::nullopt,
         /*debug_loss_report_url=*/
@@ -607,13 +633,14 @@ void SellerWorklet::V8State::ScoreAd(
   }
 
   double score;
+  mojom::RejectReason reject_reason = mojom::RejectReason::kNotAvailable;
   bool allow_component_auction = false;
   mojom::ComponentAuctionModifiedBidParamsPtr
       component_auction_modified_bid_params;
   // Try to parse the result as a number. On success, it's the desirability
   // score.
   if (!gin::ConvertFromV8(isolate, score_ad_result, &score)) {
-    // Otherwise, try it must be an object with the desireability score, and
+    // Otherwise, it must be an object with the desireability score, and
     // potentially other fields as well.
     if (!score_ad_result->IsObject()) {
       errors_out.push_back(
@@ -642,6 +669,30 @@ void SellerWorklet::V8State::ScoreAd(
     if (!result_dict.Get("allowComponentAuction", &allow_component_auction))
       allow_component_auction = false;
 
+    v8::Local<v8::Value> reject_reason_value;
+    if (score_ad_object
+            ->Get(context, v8_helper_->CreateStringFromLiteral("rejectReason"))
+            .ToLocal(&reject_reason_value) &&
+        !reject_reason_value->IsUndefined()) {
+      if (!reject_reason_value->IsString()) {
+        errors_out.push_back(base::StrCat(
+            {decision_logic_url_.spec(),
+             " rejectReason returned by scoreAd() must be a string."}));
+      } else {
+        std::string reject_reason_str;
+        result_dict.Get("rejectReason", &reject_reason_str);
+        auto reject_reason_opt = RejectReasonStringToEnum(reject_reason_str);
+
+        if (!reject_reason_opt.has_value()) {
+          errors_out.push_back(
+              base::StrCat({decision_logic_url_.spec(),
+                            " scoreAd() returned an invalid reject reason."}));
+        } else {
+          reject_reason = reject_reason_opt.value();
+        }
+      }
+    }
+
     // If this is the seller in a component auction (and thus it was passed a
     // top-level seller), need to return a
     // mojom::ComponentAuctionModifiedBidParams.
@@ -695,7 +746,7 @@ void SellerWorklet::V8State::ScoreAd(
     // Keep debug report URLs because we want to send debug loss reports if
     // seller rejected all bids.
     PostScoreAdCallbackToUserThread(
-        std::move(callback), /*score=*/0,
+        std::move(callback), /*score=*/0, reject_reason,
         /*component_auction_modified_bid_params=*/nullptr,
         scoring_signals_data_version,
         context_recycler.for_debugging_only_bindings()->TakeLossReportUrl(),
@@ -726,6 +777,7 @@ void SellerWorklet::V8State::ScoreAd(
 
   PostScoreAdCallbackToUserThread(
       std::move(callback), score,
+      /*reject_reason=*/mojom::RejectReason::kNotAvailable,
       std::move(component_auction_modified_bid_params),
       scoring_signals_data_version,
       context_recycler.for_debugging_only_bindings()->TakeLossReportUrl(),
@@ -904,6 +956,7 @@ void SellerWorklet::V8State::PostScoreAdCallbackToUserThreadOnError(
     PrivateAggregationRequests pa_requests) {
   PostScoreAdCallbackToUserThread(
       std::move(callback), /*score=*/0,
+      /*reject_reason=*/mojom::RejectReason::kNotAvailable,
       /*component_auction_modified_bid_params=*/nullptr,
       /*scoring_signals_data_version=*/absl::nullopt,
       /*debug_loss_report_url=*/absl::nullopt,
@@ -914,6 +967,7 @@ void SellerWorklet::V8State::PostScoreAdCallbackToUserThreadOnError(
 void SellerWorklet::V8State::PostScoreAdCallbackToUserThread(
     ScoreAdCallbackInternal callback,
     double score,
+    mojom::RejectReason reject_reason,
     mojom::ComponentAuctionModifiedBidParamsPtr
         component_auction_modified_bid_params,
     absl::optional<uint32_t> scoring_signals_data_version,
@@ -924,7 +978,7 @@ void SellerWorklet::V8State::PostScoreAdCallbackToUserThread(
   DCHECK_CALLED_ON_VALID_SEQUENCE(v8_sequence_checker_);
   user_thread_->PostTask(
       FROM_HERE,
-      base::BindOnce(std::move(callback), score,
+      base::BindOnce(std::move(callback), score, reject_reason,
                      std::move(component_auction_modified_bid_params),
                      scoring_signals_data_version,
                      std::move(debug_loss_report_url),
@@ -1081,6 +1135,7 @@ void SellerWorklet::ScoreAdIfReady(ScoreAdTaskList::iterator task) {
 void SellerWorklet::DeliverScoreAdCallbackOnUserThread(
     ScoreAdTaskList::iterator task,
     double score,
+    mojom::RejectReason reject_reason,
     mojom::ComponentAuctionModifiedBidParamsPtr
         component_auction_modified_bid_params,
     absl::optional<uint32_t> scoring_signals_data_version,
@@ -1089,7 +1144,6 @@ void SellerWorklet::DeliverScoreAdCallbackOnUserThread(
     PrivateAggregationRequests pa_requests,
     std::vector<std::string> errors) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(user_sequence_checker_);
-
   if (load_script_error_msg_)
     errors.insert(errors.begin(), load_script_error_msg_.value());
   if (task->trusted_scoring_signals_error_msg)
@@ -1102,7 +1156,7 @@ void SellerWorklet::DeliverScoreAdCallbackOnUserThread(
   // it does. Only useful if the SellerWorklet object is still in use, so
   // unclear how useful it would be.
   task->score_ad_client->OnScoreAdComplete(
-      score, std::move(component_auction_modified_bid_params),
+      score, reject_reason, std::move(component_auction_modified_bid_params),
       scoring_signals_data_version.value_or(0),
       scoring_signals_data_version.has_value(), debug_loss_report_url,
       debug_win_report_url, std::move(pa_requests), std::move(errors));

content/services/auction_worklet/seller_worklet.h

@@ -195,6 +195,7 @@ class CONTENT_EXPORT SellerWorklet : public mojom::SellerWorklet {
     // V8State, and avoids having to make a copy of the errors vector.
     using ScoreAdCallbackInternal = base::OnceCallback<void(
         double score,
+        mojom::RejectReason reject_reason,
         mojom::ComponentAuctionModifiedBidParamsPtr
             component_auction_modified_bid_params,
         absl::optional<uint32_t> scoring_signals_data_version,
@@ -270,6 +271,7 @@ class CONTENT_EXPORT SellerWorklet : public mojom::SellerWorklet {
     void PostScoreAdCallbackToUserThread(
         ScoreAdCallbackInternal callback,
         double score,
+        mojom::RejectReason reject_reason,
         mojom::ComponentAuctionModifiedBidParamsPtr
             component_auction_modified_bid_params,
         absl::optional<uint32_t> scoring_signals_data_version,
@@ -333,6 +335,7 @@ class CONTENT_EXPORT SellerWorklet : public mojom::SellerWorklet {
   void DeliverScoreAdCallbackOnUserThread(
       ScoreAdTaskList::iterator task,
       double score,
+      mojom::RejectReason reject_reason,
       mojom::ComponentAuctionModifiedBidParamsPtr
           component_auction_modified_bid_params,
       absl::optional<uint32_t> scoring_signals_data_version,

content/services/auction_worklet/seller_worklet_unittest.cc

@@ -47,7 +47,7 @@ namespace auction_worklet {
 namespace {
 
 using PrivateAggregationRequests =
-    std::vector<auction_worklet::mojom::PrivateAggregationRequestPtr>;
+    std::vector<mojom::PrivateAggregationRequestPtr>;
 
 // Very short time used by some tests that want to wait until just before a
 // timer triggers.
@@ -106,16 +106,17 @@ std::string CreateReportToScript(const std::string& raw_return_value,
 // A ScoreAdClient that takes a callback to call in OnScoreAdComplete().
 class TestScoreAdClient : public mojom::ScoreAdClient {
  public:
-  using ScoreAdCompleteCallback = base::OnceCallback<void(
-      double score,
-      auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr
-          component_auction_modified_bid_params,
-      uint32_t scoring_signals_data_version,
-      bool has_scoring_signals_data_version,
-      const absl::optional<GURL>& debug_loss_report_url,
-      const absl::optional<GURL>& debug_win_report_url,
-      PrivateAggregationRequests pa_requests,
-      const std::vector<std::string>& errors)>;
+  using ScoreAdCompleteCallback =
+      base::OnceCallback<void(double score,
+                              mojom::RejectReason reject_reason,
+                              mojom::ComponentAuctionModifiedBidParamsPtr
+                                  component_auction_modified_bid_params,
+                              uint32_t scoring_signals_data_version,
+                              bool has_scoring_signals_data_version,
+                              const absl::optional<GURL>& debug_loss_report_url,
+                              const absl::optional<GURL>& debug_win_report_url,
+                              PrivateAggregationRequests pa_requests,
+                              const std::vector<std::string>& errors)>;
 
   explicit TestScoreAdClient(ScoreAdCompleteCallback score_ad_complete_callback)
       : score_ad_complete_callback_(std::move(score_ad_complete_callback)) {}
@@ -133,25 +134,26 @@ class TestScoreAdClient : public mojom::ScoreAdClient {
   }
 
   // mojom::ScoreAdClient implementation:
-  void OnScoreAdComplete(
-      double score,
-      auction_worklet::mojom::ComponentAuctionModifiedBidParamsPtr
-          component_auction_modified_bid_params,
-      uint32_t scoring_signals_data_version,
-      bool has_scoring_signals_data_version,
-      const absl::optional<GURL>& debug_loss_report_url,
-      const absl::optional<GURL>& debug_win_report_url,
-      PrivateAggregationRequests pa_requests,
-      const std::vector<std::string>& errors) override {
+  void OnScoreAdComplete(double score,
+                         mojom::RejectReason reject_reason,
+                         mojom::ComponentAuctionModifiedBidParamsPtr
+                             component_auction_modified_bid_params,
+                         uint32_t scoring_signals_data_version,
+                         bool has_scoring_signals_data_version,
+                         const absl::optional<GURL>& debug_loss_report_url,
+                         const absl::optional<GURL>& debug_win_report_url,
+                         PrivateAggregationRequests pa_requests,
+                         const std::vector<std::string>& errors) override {
     std::move(score_ad_complete_callback_)
-        .Run(score, std::move(component_auction_modified_bid_params),
+        .Run(score, reject_reason,
+             std::move(component_auction_modified_bid_params),
              scoring_signals_data_version, has_scoring_signals_data_version,
              debug_loss_report_url, debug_win_report_url,
              std::move(pa_requests), errors);
   }
 
   static ScoreAdCompleteCallback ScoreAdNeverInvokedCallback() {
-    return base::BindOnce([](double score,
+    return base::BindOnce([](double score, mojom::RejectReason reject_reason,
                              mojom::ComponentAuctionModifiedBidParamsPtr
                                  component_auction_modified_bid_params,
                              uint32_t scoring_signals_data_version,
@@ -241,12 +243,15 @@ class SellerWorkletTest : public testing::Test {
       const absl::optional<GURL>& expected_debug_loss_report_url =
           absl::nullopt,
       const absl::optional<GURL>& expected_debug_win_report_url = absl::nullopt,
+      mojom::RejectReason expected_reject_reason =
+          mojom::RejectReason::kNotAvailable,
       PrivateAggregationRequests expected_pa_requests = {}) {
     RunScoreAdWithJavascriptExpectingResult(
         CreateScoreAdScript(raw_return_value), expected_score, expected_errors,
         std::move(expected_component_auction_modified_bid_params),
         expected_data_version, expected_debug_loss_report_url,
-        expected_debug_win_report_url, std::move(expected_pa_requests));
+        expected_debug_win_report_url, expected_reject_reason,
+        std::move(expected_pa_requests));
   }
 
   // Behaves just like RunScoreAdWithReturnValueExpectingResult(), but
@@ -267,6 +272,8 @@ class SellerWorkletTest : public testing::Test {
       const absl::optional<GURL>& expected_debug_loss_report_url =
           absl::nullopt,
       const absl::optional<GURL>& expected_debug_win_report_url = absl::nullopt,
+      mojom::RejectReason expected_reject_reason =
+          mojom::RejectReason::kNotAvailable,
       PrivateAggregationRequests expected_pa_requests = {}) {
     AddJavascriptResponse(&url_loader_factory_, decision_logic_url_,
                           CreateScoreAdScript(raw_return_value));
@@ -277,8 +284,8 @@ class SellerWorkletTest : public testing::Test {
         seller_worklet.get(), expected_score, expected_errors,
         std::move(expected_component_auction_modified_bid_params),
         expected_data_version, expected_debug_loss_report_url,
-        expected_debug_win_report_url, std::move(expected_pa_requests),
-        run_loop.QuitClosure());
+        expected_debug_win_report_url, expected_reject_reason,
+        std::move(expected_pa_requests), run_loop.QuitClosure());
     task_environment_.FastForwardBy(expected_duration - kTinyTime);
     EXPECT_FALSE(run_loop.AnyQuitCalled());
     task_environment_.FastForwardBy(kTinyTime);
@@ -299,6 +306,8 @@ class SellerWorkletTest : public testing::Test {
       const absl::optional<GURL>& expected_debug_loss_report_url =
           absl::nullopt,
       const absl::optional<GURL>& expected_debug_win_report_url = absl::nullopt,
+      mojom::RejectReason expected_reject_reason =
+          mojom::RejectReason::kNotAvailable,
       PrivateAggregationRequests expected_pa_requests = {}) {
     SCOPED_TRACE(javascript);
     AddJavascriptResponse(&url_loader_factory_, decision_logic_url_,
@@ -307,7 +316,8 @@ class SellerWorkletTest : public testing::Test {
         expected_score, expected_errors,
         std::move(expected_component_auction_modified_bid_params),
         expected_data_version, expected_debug_loss_report_url,
-        expected_debug_win_report_url, std::move(expected_pa_requests));
+        expected_debug_win_report_url, expected_reject_reason,
+        std::move(expected_pa_requests));
   }
 
   // Runs score_ad() script, checking result and invoking provided closure
@@ -321,6 +331,7 @@ class SellerWorkletTest : public testing::Test {
       absl::optional<uint32_t> expected_data_version,
       const absl::optional<GURL>& expected_debug_loss_report_url,
       const absl::optional<GURL>& expected_debug_win_report_url,
+      mojom::RejectReason expected_reject_reason,
       PrivateAggregationRequests expected_pa_requests,
       base::OnceClosure done_closure) {
     seller_worklet->ScoreAd(
@@ -332,6 +343,7 @@ class SellerWorkletTest : public testing::Test {
         /*trace_id=*/1,
         TestScoreAdClient::Create(base::BindOnce(
             [](double expected_score,
+               mojom::RejectReason expected_reject_reason,
                mojom::ComponentAuctionModifiedBidParamsPtr
                    expected_component_auction_modified_bid_params,
                absl::optional<uint32_t> expected_data_version,
@@ -340,6 +352,7 @@ class SellerWorkletTest : public testing::Test {
                PrivateAggregationRequests expected_pa_requests,
                std::vector<std::string> expected_errors,
                base::OnceClosure done_closure, double score,
+               mojom::RejectReason reject_reason,
                mojom::ComponentAuctionModifiedBidParamsPtr
                    component_auction_modified_bid_params,
                uint32_t data_version, bool has_data_version,
@@ -351,6 +364,8 @@ class SellerWorkletTest : public testing::Test {
               if (has_data_version)
                 maybe_data_version = data_version;
               EXPECT_EQ(expected_score, score);
+              EXPECT_EQ(static_cast<int>(expected_reject_reason),
+                        static_cast<int>(reject_reason));
               EXPECT_EQ(
                   expected_component_auction_modified_bid_params.is_null(),
                   component_auction_modified_bid_params.is_null());
@@ -373,7 +388,7 @@ class SellerWorkletTest : public testing::Test {
               EXPECT_EQ(expected_errors, errors);
               std::move(done_closure).Run();
             },
-            expected_score,
+            expected_score, expected_reject_reason,
             std::move(expected_component_auction_modified_bid_params),
             expected_data_version, expected_debug_loss_report_url,
             expected_debug_win_report_url, std::move(expected_pa_requests),
@@ -406,14 +421,16 @@ class SellerWorkletTest : public testing::Test {
       const absl::optional<GURL>& expected_debug_loss_report_url =
           absl::nullopt,
       const absl::optional<GURL>& expected_debug_win_report_url = absl::nullopt,
+      mojom::RejectReason expected_reject_reason =
+          mojom::RejectReason::kNotAvailable,
       PrivateAggregationRequests expected_pa_requests = {}) {
     base::RunLoop run_loop;
     RunScoreAdOnWorkletAsync(
         seller_worklet, expected_score, expected_errors,
         std::move(expected_component_auction_modified_bid_params),
         expected_data_version, expected_debug_loss_report_url,
-        expected_debug_win_report_url, std::move(expected_pa_requests),
-        run_loop.QuitClosure());
+        expected_debug_win_report_url, expected_reject_reason,
+        std::move(expected_pa_requests), run_loop.QuitClosure());
     run_loop.Run();
   }
 
@@ -429,6 +446,8 @@ class SellerWorkletTest : public testing::Test {
       const absl::optional<GURL>& expected_debug_loss_report_url =
           absl::nullopt,
       const absl::optional<GURL>& expected_debug_win_report_url = absl::nullopt,
+      mojom::RejectReason expected_reject_reason =
+          mojom::RejectReason::kNotAvailable,
       PrivateAggregationRequests expected_pa_requests = {}) {
     auto seller_worklet = CreateWorklet();
     ASSERT_TRUE(seller_worklet);
@@ -436,7 +455,8 @@ class SellerWorkletTest : public testing::Test {
         seller_worklet.get(), expected_score, expected_errors,
         std::move(expected_component_auction_modified_bid_params),
         expected_data_version, expected_debug_loss_report_url,
-        expected_debug_win_report_url, std::move(expected_pa_requests));
+        expected_debug_win_report_url, expected_reject_reason,
+        std::move(expected_pa_requests));
   }
 
   // Configures `url_loader_factory_` to return a report_result() script created
@@ -658,7 +678,7 @@ class SellerWorkletTest : public testing::Test {
   uint32_t browser_signal_bidding_duration_msecs_;
   double browser_signal_desireability_;
   double browser_signal_highest_scoring_other_bid_;
-  auction_worklet::mojom::ComponentAuctionReportResultParamsPtr
+  mojom::ComponentAuctionReportResultParamsPtr
       browser_signals_component_auction_report_result_params_;
   absl::optional<uint32_t> browser_signal_data_version_;
   absl::optional<base::TimeDelta> seller_timeout_;
@@ -901,6 +921,80 @@ TEST_F(SellerWorkletTest, ScoreAdAd) {
           /*ad=*/"[[35]]", /*bid=*/0, /*has_bid=*/false));
 }
 
+// Test the `rejectReason` output field of scoreAd().
+TEST_F(SellerWorkletTest, ScoreAdRejectReason) {
+  const struct {
+    std::string reason_str;
+    mojom::RejectReason reason_enum;
+  } kTestCases[] = {
+      {"not-available", mojom::RejectReason::kNotAvailable},
+      {"invalid-bid", mojom::RejectReason::kInvalidBid},
+      {"bid-below-auction-floor", mojom::RejectReason::kBidBelowAuctionFloor},
+      {"pending-approval-by-exchange",
+       mojom::RejectReason::kPendingApprovalByExchange},
+      {"disapproved-by-exchange", mojom::RejectReason::kDisapprovedByExchange},
+      {"blocked-by-publisher", mojom::RejectReason::kBlockedByPublisher},
+      {"language-exclusions", mojom::RejectReason::kLanguageExclusions},
+      {"category-exclusions", mojom::RejectReason::kCategoryExclusions},
+  };
+
+  for (const auto& test_case : kTestCases) {
+    RunScoreAdWithReturnValueExpectingResult(
+        base::StringPrintf(R"({desirability:-1, rejectReason: '%s'})",
+                           test_case.reason_str.c_str()),
+        0,
+        /*expected_errors=*/{}, mojom::ComponentAuctionModifiedBidParamsPtr(),
+        /*expected_data_version=*/absl::nullopt,
+        /*expected_debug_loss_report_url=*/absl::nullopt,
+        /*expected_debug_win_report_url=*/absl::nullopt, test_case.reason_enum);
+  }
+
+  // Default reject reason is mojom::RejectReason::kNotAvailable, if scoreAd()
+  // does not return one.
+  RunScoreAdWithReturnValueExpectingResult(
+      "{desirability:-1}", 0,
+      /*expected_errors=*/{}, mojom::ComponentAuctionModifiedBidParamsPtr(),
+      /*expected_data_version=*/absl::nullopt,
+      /*expected_debug_loss_report_url=*/absl::nullopt,
+      /*expected_debug_win_report_url=*/absl::nullopt,
+      mojom::RejectReason::kNotAvailable);
+
+  // Reject reason is ignored when desirability is positive.
+  RunScoreAdWithReturnValueExpectingResult(
+      "{desirability:3, rejectReason: 'invalid-bid'}", 3,
+      /*expected_errors=*/{}, mojom::ComponentAuctionModifiedBidParamsPtr(),
+      /*expected_data_version=*/absl::nullopt,
+      /*expected_debug_loss_report_url=*/absl::nullopt,
+      /*expected_debug_win_report_url=*/absl::nullopt,
+      /*expected_reject_reason*/ mojom::RejectReason::kNotAvailable);
+}
+
+// Invalid `rejectReason` output of scoreAd() results in error.
+TEST_F(SellerWorkletTest, ScoreAdInvalidRejectReason) {
+  // Reject reason string returned by seller script is case sensitive.
+  RunScoreAdWithReturnValueExpectingResult(
+      "{desirability:-1, rejectReason: 'INVALID-BID'}", 0,
+      /*expected_errors=*/
+      {"https://url.test/ scoreAd() returned an invalid reject reason."},
+      mojom::ComponentAuctionModifiedBidParamsPtr(),
+      /*expected_data_version=*/absl::nullopt,
+      /*expected_debug_loss_report_url=*/absl::nullopt,
+      /*expected_debug_win_report_url=*/absl::nullopt,
+      /*expected_reject_reason*/ mojom::RejectReason::kNotAvailable);
+
+  // Reject reason returned by seller script must be a string.
+  RunScoreAdWithReturnValueExpectingResult(
+      "{desirability:-1, rejectReason: 2}", 0,
+      /*expected_errors=*/
+      {"https://url.test/ rejectReason returned by scoreAd() must be a "
+       "string."},
+      mojom::ComponentAuctionModifiedBidParamsPtr(),
+      /*expected_data_version=*/absl::nullopt,
+      /*expected_debug_loss_report_url=*/absl::nullopt,
+      /*expected_debug_win_report_url=*/absl::nullopt,
+      /*expected_reject_reason*/ mojom::RejectReason::kNotAvailable);
+}
+
 // Test the `bid` output field of scoreAd().
 TEST_F(SellerWorkletTest, ScoreAdModifiesBid) {
   // When `browser_signals_other_seller_` is not top a top-level auction (i.e.
@@ -1296,6 +1390,8 @@ TEST_F(SellerWorkletTest, ScoreAdParallelBeforeLoadComplete) {
                              /*expected_data_version=*/absl::nullopt,
                              /*expected_debug_loss_report_url=*/absl::nullopt,
                              /*expected_debug_win_report_url=*/absl::nullopt,
+                             /*expected_reject_reason=*/
+                             mojom::RejectReason::kNotAvailable,
                              /*expected_pa_requests=*/{},
                              base::BindLambdaForTesting([&]() {
                                ++num_completed_worklets;
@@ -1338,6 +1434,8 @@ TEST_F(SellerWorkletTest, ScoreAdParallelAfterLoadComplete) {
                              /*expected_data_version=*/absl::nullopt,
                              /*expected_debug_loss_report_url=*/absl::nullopt,
                              /*expected_debug_win_report_url=*/absl::nullopt,
+                             /*expected_reject_reason=*/
+                             mojom::RejectReason::kNotAvailable,
                              /*expected_pa_requests=*/{},
                              base::BindLambdaForTesting([&]() {
                                ++num_completed_worklets;
@@ -1402,6 +1500,8 @@ TEST_F(SellerWorkletTest, ScoreAdParallelTrustedScoringSignalsNotBatched) {
                              /*expected_data_version=*/i,
                              /*expected_debug_loss_report_url=*/absl::nullopt,
                              /*expected_debug_win_report_url=*/absl::nullopt,
+                             /*expected_reject_reason=*/
+                             mojom::RejectReason::kNotAvailable,
                              /*expected_pa_requests=*/{},
                              base::BindLambdaForTesting([&]() {
                                ++num_completed_worklets;
@@ -1469,6 +1569,8 @@ TEST_F(SellerWorkletTest, ScoreAdParallelTrustedScoringSignalsBatched1) {
                              /*expected_data_version=*/absl::nullopt,
                              /*expected_debug_loss_report_url=*/absl::nullopt,
                              /*expected_debug_win_report_url=*/absl::nullopt,
+                             /*expected_reject_reason=*/
+                             mojom::RejectReason::kNotAvailable,
                              /*expected_pa_requests=*/{},
                              base::BindLambdaForTesting([&]() {
                                ++num_completed_worklets;
@@ -1527,6 +1629,8 @@ TEST_F(SellerWorkletTest, ScoreAdParallelTrustedScoringSignalsBatched2) {
                              /*expected_data_version=*/10,
                              /*expected_debug_loss_report_url=*/absl::nullopt,
                              /*expected_debug_win_report_url=*/absl::nullopt,
+                             /*expected_reject_reason=*/
+                             mojom::RejectReason::kNotAvailable,
                              /*expected_pa_requests=*/{},
                              base::BindLambdaForTesting([&]() {
                                ++num_completed_worklets;
@@ -1594,6 +1698,8 @@ TEST_F(SellerWorkletTest, ScoreAdParallelTrustedScoringSignalsBatched3) {
                              /*expected_data_version=*/10,
                              /*expected_debug_loss_report_url=*/absl::nullopt,
                              /*expected_debug_win_report_url=*/absl::nullopt,
+                             /*expected_reject_reason=*/
+                             mojom::RejectReason::kNotAvailable,
                              /*expected_pa_requests=*/{},
                              base::BindLambdaForTesting([&]() {
                                ++num_completed_worklets;
@@ -1849,7 +1955,7 @@ TEST_F(SellerWorkletTest, ReportResultTopLevelSeller) {
       mojom::ComponentAuctionOtherSeller::NewTopLevelSeller(
           url::Origin::Create(GURL("https://top.seller.test")));
   browser_signals_component_auction_report_result_params_ =
-      auction_worklet::mojom::ComponentAuctionReportResultParams::New(
+      mojom::ComponentAuctionReportResultParams::New(
           /*top_level_seller_signals=*/"null",
           /*modified_bid=*/0,
           /*has_modified_bid=*/false);
@@ -1879,7 +1985,7 @@ TEST_F(SellerWorkletTest, ReportResultComponentSeller) {
       mojom::ComponentAuctionOtherSeller::NewTopLevelSeller(
           url::Origin::Create(GURL("https://top.seller.test")));
   browser_signals_component_auction_report_result_params_ =
-      auction_worklet::mojom::ComponentAuctionReportResultParams::New(
+      mojom::ComponentAuctionReportResultParams::New(
           /*top_level_seller_signals=*/"null",
           /*modified_bid=*/0,
           /*has_modified_bid=*/false);
@@ -1923,7 +2029,7 @@ TEST_F(SellerWorkletTest, ReportResultTopLevelSellerSignals) {
       mojom::ComponentAuctionOtherSeller::NewTopLevelSeller(
           url::Origin::Create(GURL("https://top.seller.test")));
   browser_signals_component_auction_report_result_params_ =
-      auction_worklet::mojom::ComponentAuctionReportResultParams::New(
+      mojom::ComponentAuctionReportResultParams::New(
           /*top_level_seller_signals=*/"null",
           /*modified_bid=*/0,
           /*has_modified_bid=*/false);
@@ -1965,7 +2071,7 @@ TEST_F(SellerWorkletTest, ReportResultModifiedBid) {
       mojom::ComponentAuctionOtherSeller::NewTopLevelSeller(
           url::Origin::Create(GURL("https://top.seller.test")));
   browser_signals_component_auction_report_result_params_ =
-      auction_worklet::mojom::ComponentAuctionReportResultParams::New(
+      mojom::ComponentAuctionReportResultParams::New(
           /*top_level_seller_signals=*/"null",
           /*modified_bid=*/4,
           /*has_modified_bid=*/true);
@@ -2365,7 +2471,7 @@ TEST_F(SellerWorkletTest, ScriptIsolation) {
           seller_timeout_,
           /*trace_id=*/1,
           TestScoreAdClient::Create(base::BindLambdaForTesting(
-              [&run_loop](double score,
+              [&run_loop](double score, mojom::RejectReason reject_reason,
                           mojom::ComponentAuctionModifiedBidParamsPtr
                               component_auction_modified_bid_params,
                           uint32_t scoring_signals_data_version,
@@ -2483,6 +2589,8 @@ TEST_F(SellerWorkletTest, PauseOnStart) {
                            /*expected_data_version=*/absl::nullopt,
                            /*expected_debug_loss_report_url=*/absl::nullopt,
                            /*expected_debug_win_report_url=*/absl::nullopt,
+                           /*expected_reject_reason=*/
+                           mojom::RejectReason::kNotAvailable,
                            /*expected_pa_requests=*/{}, run_loop.QuitClosure());
 
   // Give it a chance to fetch.
@@ -2565,6 +2673,8 @@ TEST_F(SellerWorkletTest, BasicV8Debug) {
       /*expected_data_version=*/absl::nullopt,
       /*expected_debug_loss_report_url=*/absl::nullopt,
       /*expected_debug_win_report_url=*/absl::nullopt,
+      /*expected_reject_reason=*/
+      mojom::RejectReason::kNotAvailable,
       /*expected_pa_requests=*/{}, run_loop1.QuitClosure());
 
   decision_logic_url_ = kUrl2;
@@ -2578,6 +2688,8 @@ TEST_F(SellerWorkletTest, BasicV8Debug) {
       /*expected_data_version=*/absl::nullopt,
       /*expected_debug_loss_report_url=*/absl::nullopt,
       /*expected_debug_win_report_url=*/absl::nullopt,
+      /*expected_reject_reason=*/
+      mojom::RejectReason::kNotAvailable,
       /*expected_pa_requests=*/{}, run_loop2.QuitClosure());
 
   int id1 = worklet_impl1->context_group_id_for_testing();
@@ -2693,22 +2805,27 @@ TEST_F(SellerWorkletTest, BasicDevToolsDebug) {
   auto worklet1 = CreateWorklet(/*pause_for_debugger_on_start=*/true);
   base::RunLoop run_loop1;
   RunScoreAdOnWorkletAsync(
-      worklet1.get(), 100.5, {}, mojom::ComponentAuctionModifiedBidParamsPtr(),
+      worklet1.get(), /*expected_score=*/100.5, /*expected_errors=*/{},
+      mojom::ComponentAuctionModifiedBidParamsPtr(),
       /*expected_data_version=*/absl::nullopt,
       /*expected_debug_loss_report_url=*/absl::nullopt,
       /*expected_debug_win_report_url=*/absl::nullopt,
+      /*expected_reject_reason=*/
+      mojom::RejectReason::kNotAvailable,
       /*expected_pa_requests=*/{}, run_loop1.QuitClosure());
 
   decision_logic_url_ = GURL(kUrl2);
   auto worklet2 = CreateWorklet(/*pause_for_debugger_on_start=*/true);
   base::RunLoop run_loop2;
-  RunScoreAdOnWorkletAsync(worklet2.get(), 0,
+  RunScoreAdOnWorkletAsync(worklet2.get(), /*expected_score=*/0,
                            {"http://example.org/second.js scoreAd() did not "
                             "return an object or a number."},
                            mojom::ComponentAuctionModifiedBidParamsPtr(),
                            /*expected_data_version=*/absl::nullopt,
                            /*expected_debug_loss_report_url=*/absl::nullopt,
                            /*expected_debug_win_report_url=*/absl::nullopt,
+                           /*expected_reject_reason=*/
+                           mojom::RejectReason::kNotAvailable,
                            /*expected_pa_requests=*/{},
                            run_loop2.QuitClosure());
 
@@ -2848,11 +2965,14 @@ TEST_F(SellerWorkletTest, InstrumentationBreakpoints) {
   decision_logic_url_ = GURL(kUrl);
   auto worklet = CreateWorklet(/*pause_for_debugger_on_start=*/true);
   base::RunLoop run_loop;
-  RunScoreAdOnWorkletAsync(worklet.get(), 1.0, {},
+  RunScoreAdOnWorkletAsync(worklet.get(), /*expected_score=*/1.0,
+                           /*expected_errors=*/{},
                            mojom::ComponentAuctionModifiedBidParamsPtr(),
                            /*expected_data_version=*/absl::nullopt,
                            /*expected_debug_loss_report_url=*/absl::nullopt,
                            /*expected_debug_win_report_url=*/absl::nullopt,
+                           /*expected_reject_reason=*/
+                           mojom::RejectReason::kNotAvailable,
                            /*expected_pa_requests=*/{}, run_loop.QuitClosure());
 
   mojo::AssociatedRemote<blink::mojom::DevToolsAgent> agent;
@@ -2926,10 +3046,13 @@ TEST_F(SellerWorkletTest, InstrumentationBreakpoints) {
   // remove it.
   base::RunLoop run_loop3;
   RunScoreAdOnWorkletAsync(
-      worklet.get(), 1.0, {}, mojom::ComponentAuctionModifiedBidParamsPtr(),
+      worklet.get(), /*expected_score=*/1.0, /*expected_errors=*/{},
+      mojom::ComponentAuctionModifiedBidParamsPtr(),
       /*expected_data_version=*/absl::nullopt,
       /*expected_debug_loss_report_url=*/absl::nullopt,
       /*expected_debug_win_report_url=*/absl::nullopt,
+      /*expected_reject_reason=*/
+      mojom::RejectReason::kNotAvailable,
       /*expected_pa_requests=*/{}, run_loop3.QuitClosure());
 
   TestDevToolsAgentClient::Event breakpoint_hit3 =
@@ -2988,10 +3111,13 @@ TEST_F(SellerWorkletTest, UnloadWhilePaused) {
       R"({"id":4,"method":"Runtime.runIfWaitingForDebugger","params":{}})");
 
   RunScoreAdOnWorkletAsync(
-      worklet.get(), 1.0, {}, mojom::ComponentAuctionModifiedBidParamsPtr(),
+      worklet.get(), /*expected_score=*/1.0, /*expected_errors=*/{},
+      mojom::ComponentAuctionModifiedBidParamsPtr(),
       /*expected_data_version=*/absl::nullopt,
       /*expected_debug_loss_report_url=*/absl::nullopt,
       /*expected_debug_win_report_url=*/absl::nullopt,
+      /*expected_reject_reason=*/
+      mojom::RejectReason::kNotAvailable,
       /*expected_pa_requests=*/{}, base::BindOnce([]() {
         ADD_FAILURE() << "scoreAd shouldn't actually get to finish.";
       }));
@@ -3399,7 +3525,7 @@ TEST_F(SellerWorkletBiddingAndScoringDebugReportingAPIEnabledTest,
         seller_timeout_,
         /*trace_id=*/1,
         TestScoreAdClient::Create(base::BindLambdaForTesting(
-            [&run_loop](double score,
+            [&run_loop](double score, mojom::RejectReason reject_reason,
                         mojom::ComponentAuctionModifiedBidParamsPtr
                             component_auction_modified_bid_params,
                         uint32_t scoring_signals_data_version,
@@ -3436,15 +3562,15 @@ class SellerWorkletPrivateAggregationEnabledTest : public SellerWorkletTest {
 };
 
 TEST_F(SellerWorkletPrivateAggregationEnabledTest, ScoreAd) {
-  auction_worklet::mojom::PrivateAggregationRequestPtr kExpectedRequest1 =
-      auction_worklet::mojom::PrivateAggregationRequest::New(
+  mojom::PrivateAggregationRequestPtr kExpectedRequest1 =
+      mojom::PrivateAggregationRequest::New(
           content::mojom::AggregatableReportHistogramContribution::New(
               /*bucket=*/123,
               /*value=*/45),
           content::mojom::AggregationServiceMode::kDefault,
           content::mojom::DebugModeDetails::New());
-  auction_worklet::mojom::PrivateAggregationRequestPtr kExpectedRequest2 =
-      auction_worklet::mojom::PrivateAggregationRequest::New(
+  mojom::PrivateAggregationRequestPtr kExpectedRequest2 =
+      mojom::PrivateAggregationRequest::New(
           content::mojom::AggregatableReportHistogramContribution::New(
               /*bucket=*/absl::MakeInt128(/*high=*/1, /*low=*/0),
               /*value=*/1),
@@ -3464,6 +3590,7 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ScoreAd) {
         /*expected_data_version=*/absl::nullopt,
         /*expected_debug_loss_report_url=*/absl::nullopt,
         /*expected_debug_win_report_url=*/absl::nullopt,
+        /*expected_reject_reason=*/mojom::RejectReason::kNotAvailable,
         std::move(expected_pa_requests));
   }
 
@@ -3481,6 +3608,7 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ScoreAd) {
         /*expected_data_version=*/absl::nullopt,
         /*expected_debug_loss_report_url=*/absl::nullopt,
         /*expected_debug_win_report_url=*/absl::nullopt,
+        /*expected_reject_reason=*/mojom::RejectReason::kNotAvailable,
         std::move(expected_pa_requests));
   }
 
@@ -3498,6 +3626,7 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ScoreAd) {
         /*expected_data_version=*/absl::nullopt,
         /*expected_debug_loss_report_url=*/absl::nullopt,
         /*expected_debug_win_report_url=*/absl::nullopt,
+        /*expected_reject_reason=*/mojom::RejectReason::kNotAvailable,
         std::move(expected_pa_requests));
   }
 
@@ -3518,6 +3647,7 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ScoreAd) {
         /*expected_data_version=*/absl::nullopt,
         /*expected_debug_loss_report_url=*/absl::nullopt,
         /*expected_debug_win_report_url=*/absl::nullopt,
+        /*expected_reject_reason=*/mojom::RejectReason::kNotAvailable,
         std::move(expected_pa_requests));
   }
 
@@ -3537,18 +3667,18 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ScoreAd) {
         /*expected_data_version=*/absl::nullopt,
         /*expected_debug_loss_report_url=*/absl::nullopt,
         /*expected_debug_win_report_url=*/absl::nullopt,
+        /*expected_reject_reason=*/mojom::RejectReason::kNotAvailable,
         std::move(expected_pa_requests));
   }
 
   // Debug mode enabled with debug key
   {
     PrivateAggregationRequests expected_pa_requests;
-    expected_pa_requests.push_back(
-        auction_worklet::mojom::PrivateAggregationRequest::New(
-            kExpectedRequest1->contribution->Clone(),
-            content::mojom::AggregationServiceMode::kDefault,
-            content::mojom::DebugModeDetails::New(
-                /*is_enabled=*/true, content::mojom::DebugKey::New(1234u))));
+    expected_pa_requests.push_back(mojom::PrivateAggregationRequest::New(
+        kExpectedRequest1->contribution->Clone(),
+        content::mojom::AggregationServiceMode::kDefault,
+        content::mojom::DebugModeDetails::New(
+            /*is_enabled=*/true, content::mojom::DebugKey::New(1234u))));
 
     RunScoreAdWithJavascriptExpectingResult(
         CreateScoreAdScript("5",
@@ -3561,24 +3691,23 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ScoreAd) {
         /*expected_data_version=*/absl::nullopt,
         /*expected_debug_loss_report_url=*/absl::nullopt,
         /*expected_debug_win_report_url=*/absl::nullopt,
+        /*expected_reject_reason=*/mojom::RejectReason::kNotAvailable,
         std::move(expected_pa_requests));
   }
 
   // Debug mode enabled without debug key, but with multiple requests
   {
     PrivateAggregationRequests expected_pa_requests;
-    expected_pa_requests.push_back(
-        auction_worklet::mojom::PrivateAggregationRequest::New(
-            kExpectedRequest1->contribution->Clone(),
-            content::mojom::AggregationServiceMode::kDefault,
-            content::mojom::DebugModeDetails::New(
-                /*is_enabled=*/true, /*debug_key=*/nullptr)));
-    expected_pa_requests.push_back(
-        auction_worklet::mojom::PrivateAggregationRequest::New(
-            kExpectedRequest2->contribution->Clone(),
-            content::mojom::AggregationServiceMode::kDefault,
-            content::mojom::DebugModeDetails::New(
-                /*is_enabled=*/true, /*debug_key=*/nullptr)));
+    expected_pa_requests.push_back(mojom::PrivateAggregationRequest::New(
+        kExpectedRequest1->contribution->Clone(),
+        content::mojom::AggregationServiceMode::kDefault,
+        content::mojom::DebugModeDetails::New(
+            /*is_enabled=*/true, /*debug_key=*/nullptr)));
+    expected_pa_requests.push_back(mojom::PrivateAggregationRequest::New(
+        kExpectedRequest2->contribution->Clone(),
+        content::mojom::AggregationServiceMode::kDefault,
+        content::mojom::DebugModeDetails::New(
+            /*is_enabled=*/true, /*debug_key=*/nullptr)));
 
     RunScoreAdWithJavascriptExpectingResult(
         CreateScoreAdScript("5",
@@ -3593,20 +3722,21 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ScoreAd) {
         /*expected_data_version=*/absl::nullopt,
         /*expected_debug_loss_report_url=*/absl::nullopt,
         /*expected_debug_win_report_url=*/absl::nullopt,
+        /*expected_reject_reason=*/mojom::RejectReason::kNotAvailable,
         std::move(expected_pa_requests));
   }
 }
 
 TEST_F(SellerWorkletPrivateAggregationEnabledTest, ReportResult) {
-  auction_worklet::mojom::PrivateAggregationRequestPtr kExpectedRequest1 =
-      auction_worklet::mojom::PrivateAggregationRequest::New(
+  mojom::PrivateAggregationRequestPtr kExpectedRequest1 =
+      mojom::PrivateAggregationRequest::New(
           content::mojom::AggregatableReportHistogramContribution::New(
               /*bucket=*/123,
               /*value=*/45),
           content::mojom::AggregationServiceMode::kDefault,
           content::mojom::DebugModeDetails::New());
-  auction_worklet::mojom::PrivateAggregationRequestPtr kExpectedRequest2 =
-      auction_worklet::mojom::PrivateAggregationRequest::New(
+  mojom::PrivateAggregationRequestPtr kExpectedRequest2 =
+      mojom::PrivateAggregationRequest::New(
           content::mojom::AggregatableReportHistogramContribution::New(
               /*bucket=*/absl::MakeInt128(/*high=*/1, /*low=*/0),
               /*value=*/1),
@@ -3696,12 +3826,11 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ReportResult) {
   // Debug mode enabled with debug key
   {
     PrivateAggregationRequests expected_pa_requests;
-    expected_pa_requests.push_back(
-        auction_worklet::mojom::PrivateAggregationRequest::New(
-            kExpectedRequest1->contribution->Clone(),
-            content::mojom::AggregationServiceMode::kDefault,
-            content::mojom::DebugModeDetails::New(
-                /*is_enabled=*/true, content::mojom::DebugKey::New(1234u))));
+    expected_pa_requests.push_back(mojom::PrivateAggregationRequest::New(
+        kExpectedRequest1->contribution->Clone(),
+        content::mojom::AggregationServiceMode::kDefault,
+        content::mojom::DebugModeDetails::New(
+            /*is_enabled=*/true, content::mojom::DebugKey::New(1234u))));
 
     RunReportResultCreatedScriptExpectingResult(
         "5",
@@ -3718,18 +3847,16 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ReportResult) {
   // Debug mode enabled without debug key, but with multiple requests
   {
     PrivateAggregationRequests expected_pa_requests;
-    expected_pa_requests.push_back(
-        auction_worklet::mojom::PrivateAggregationRequest::New(
-            kExpectedRequest1->contribution->Clone(),
-            content::mojom::AggregationServiceMode::kDefault,
-            content::mojom::DebugModeDetails::New(
-                /*is_enabled=*/true, /*debug_key=*/nullptr)));
-    expected_pa_requests.push_back(
-        auction_worklet::mojom::PrivateAggregationRequest::New(
-            kExpectedRequest2->contribution->Clone(),
-            content::mojom::AggregationServiceMode::kDefault,
-            content::mojom::DebugModeDetails::New(
-                /*is_enabled=*/true, /*debug_key=*/nullptr)));
+    expected_pa_requests.push_back(mojom::PrivateAggregationRequest::New(
+        kExpectedRequest1->contribution->Clone(),
+        content::mojom::AggregationServiceMode::kDefault,
+        content::mojom::DebugModeDetails::New(
+            /*is_enabled=*/true, /*debug_key=*/nullptr)));
+    expected_pa_requests.push_back(mojom::PrivateAggregationRequest::New(
+        kExpectedRequest2->contribution->Clone(),
+        content::mojom::AggregationServiceMode::kDefault,
+        content::mojom::DebugModeDetails::New(
+            /*is_enabled=*/true, /*debug_key=*/nullptr)));
 
     RunReportResultCreatedScriptExpectingResult(
         "5",
@@ -3784,6 +3911,7 @@ TEST_F(SellerWorkletPrivateAggregationDisabledTest, ScoreAd) {
       /*expected_data_version=*/absl::nullopt,
       /*expected_debug_loss_report_url=*/absl::nullopt,
       /*expected_debug_win_report_url=*/absl::nullopt,
+      /*expected_reject_reason=*/mojom::RejectReason::kNotAvailable,
       /*expected_pa_requests=*/{});
 }