diff --git a/azure/azevents/azevents.go b/azure/azevents/azevents.go
index 439bac1..87f99ee 100644
--- a/azure/azevents/azevents.go
+++ b/azure/azevents/azevents.go
@@ -247,7 +247,8 @@ func (s *Server) RegisterHandlers(r chi.Router) {
 		portfolioIDs := []pacta.PortfolioID{}
 		var ranAt time.Time
 		now := s.now()
-		err := s.db.Transactional(r.Context(), func(tx db.Tx) error {
+		// We use a background context here rather than the one from the request so that it cannot be cancelled upstream.
+		err := s.db.Transactional(context.Background(), func(tx db.Tx) error {
 			incompleteUploads, err := s.db.IncompleteUploads(tx, req.Data.Request.IncompleteUploadIDs)
 			if err != nil {
 				return fmt.Errorf("reading incomplete uploads: %w", err)
@@ -271,7 +272,9 @@ func (s *Server) RegisterHandlers(r chi.Router) {
 				} else if *holdingsDate != *iu.HoldingsDate {
 					return fmt.Errorf("multiple holdings dates found for incomplete uploads: %+v", incompleteUploads)
 				}
-				ranAt = iu.RanAt
+				if iu.RanAt.After(ranAt) {
+					ranAt = iu.RanAt
+				}
 			}
 			for i, output := range req.Data.Outputs {
 				blobID, err := s.db.CreateBlob(tx, &output.Blob)
@@ -294,9 +297,7 @@ func (s *Server) RegisterHandlers(r chi.Router) {
 				err := s.db.UpdateIncompleteUpload(
 					tx,
 					iu.ID,
-					db.SetIncompleteUploadCompletedAt(now),
-					db.SetIncompleteUploadFailureMessage(""),
-					db.SetIncompleteUploadFailureCode(""))
+					db.SetIncompleteUploadCompletedAt(now))
 				if err != nil {
 					return fmt.Errorf("updating incomplete upload %d: %w", i, err)
 				}
diff --git a/cmd/runner/BUILD.bazel b/cmd/runner/BUILD.bazel
index 27b2f8b..080d643 100644
--- a/cmd/runner/BUILD.bazel
+++ b/cmd/runner/BUILD.bazel
@@ -71,4 +71,4 @@ oci_tarball(
     name = "image_tarball",
     image = ":image",
     repo_tags = [],
-)
\ No newline at end of file
+)
diff --git a/cmd/server/pactasrv/BUILD.bazel b/cmd/server/pactasrv/BUILD.bazel
index b03dab7..ee7f21b 100644
--- a/cmd/server/pactasrv/BUILD.bazel
+++ b/cmd/server/pactasrv/BUILD.bazel
@@ -28,5 +28,6 @@ go_library(
         "@com_github_go_chi_jwtauth_v5//:jwtauth",
         "@com_github_google_uuid//:uuid",
         "@org_uber_go_zap//:zap",
+        "@org_uber_go_zap//zapcore",
     ],
 )
diff --git a/cmd/server/pactasrv/incomplete_upload.go b/cmd/server/pactasrv/incomplete_upload.go
index c905264..3d3a1f9 100644
--- a/cmd/server/pactasrv/incomplete_upload.go
+++ b/cmd/server/pactasrv/incomplete_upload.go
@@ -10,11 +10,11 @@ import (
 	api "github.com/RMI/pacta/openapi/pacta"
 	"github.com/RMI/pacta/pacta"
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 )
 
 // (GET /incomplete-uploads)
 func (s *Server) ListIncompleteUploads(ctx context.Context, request api.ListIncompleteUploadsRequestObject) (api.ListIncompleteUploadsResponseObject, error) {
-	// TODO(#12) Implement Authorization
 	ownerID, err := s.getUserOwnerID(ctx)
 	if err != nil {
 		return nil, err
@@ -96,18 +96,19 @@ func (s *Server) checkIncompleteUploadAuthorization(ctx context.Context, id pact
 		return nil, err
 	}
 	// Extracted to a common variable so that we return the same response for not found and unauthorized.
-	notFoundErr := func(err error) error {
-		return oapierr.NotFound("incomplete upload not found", zap.String("incomplete_upload_id", string(id)), zap.Error(err))
+	notFoundErr := func(fields ...zapcore.Field) error {
+		fs := append(fields, zap.String("incomplete_upload_id", string(id)))
+		return oapierr.NotFound("incomplete upload not found", fs...)
 	}
 	iu, err := s.DB.IncompleteUpload(s.DB.NoTxn(ctx), id)
 	if err != nil {
 		if db.IsNotFound(err) {
-			return nil, notFoundErr(err)
+			return nil, notFoundErr(zap.Error(err))
 		}
 		return nil, oapierr.Internal("failed to look up incomplete upload", zap.String("incomplete_upload_id", string(id)), zap.Error(err))
 	}
 	if iu.Owner.ID != actorOwnerID {
-		return nil, notFoundErr(fmt.Errorf("incomplete upload does not belong to user: owner=%s actor=%s", iu.Owner.ID, actorOwnerID))
+		return nil, notFoundErr(zap.Error(fmt.Errorf("incomplete upload does not belong to user")), zap.String("owner_id", string(iu.Owner.ID)), zap.String("actor_id", string(actorOwnerID)))
 	}
 	return iu, nil
 }
diff --git a/cmd/server/pactasrv/portfolio.go b/cmd/server/pactasrv/portfolio.go
index 9826a1f..b33a743 100644
--- a/cmd/server/pactasrv/portfolio.go
+++ b/cmd/server/pactasrv/portfolio.go
@@ -10,6 +10,7 @@ import (
 	api "github.com/RMI/pacta/openapi/pacta"
 	"github.com/RMI/pacta/pacta"
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 )
 
 // (GET /portfolios)
@@ -95,18 +96,19 @@ func (s *Server) checkPortfolioAuthorization(ctx context.Context, id pacta.Portf
 		return nil, err
 	}
 	// Extracted to a common variable so that we return the same response for not found and unauthorized.
-	notFoundErr := func(err error) error {
-		return oapierr.NotFound("portfolio not found", zap.String("portfolio_id", string(id)), zap.Error(err))
+	notFoundErr := func(fields ...zapcore.Field) error {
+		fs := append(fields, zap.String("portfolio_id", string(id)))
+		return oapierr.NotFound("portfolio not found", fs...)
 	}
 	iu, err := s.DB.Portfolio(s.DB.NoTxn(ctx), id)
 	if err != nil {
 		if db.IsNotFound(err) {
-			return nil, notFoundErr(err)
+			return nil, notFoundErr(zap.Error(err))
 		}
 		return nil, oapierr.Internal("failed to look up portfolio", zap.String("portfolio_id", string(id)), zap.Error(err))
 	}
 	if iu.Owner.ID != actorOwnerID {
-		return nil, notFoundErr(fmt.Errorf("portfolio does not belong to user: owner=%s actor=%s", iu.Owner.ID, actorOwnerID))
+		return nil, notFoundErr(zap.Error(fmt.Errorf("portfolio does not belong to user")), zap.String("owner", string(iu.Owner.ID)), zap.String("actor", string(actorOwnerID)))
 	}
 	return iu, nil
 }
diff --git a/cmd/server/pactasrv/upload.go b/cmd/server/pactasrv/upload.go
index 22bd3a9..4650b0b 100644
--- a/cmd/server/pactasrv/upload.go
+++ b/cmd/server/pactasrv/upload.go
@@ -31,10 +31,12 @@ func (s *Server) StartPortfolioUpload(ctx context.Context, request api.StartPort
 		return nil, err
 	}
 	n := len(request.Body.Items)
-	blobs := make([]*pacta.Blob, n)
-	resp := api.StartPortfolioUpload200JSONResponse{
-		Items: make([]api.StartPortfolioUploadRespItem, n),
+	if n > 25 {
+		// TODO(#71) Implement basic limits
+		return nil, oapierr.BadRequest("too many items")
 	}
+	blobs := make([]*pacta.Blob, n)
+	respItems := make([]api.StartPortfolioUploadRespItem, n)
 	for i, item := range request.Body.Items {
 		fn := item.FileName
 		extStr := filepath.Ext(fn)
@@ -46,13 +48,13 @@ func (s *Server) StartPortfolioUpload(ctx context.Context, request api.StartPort
 				zap.String("file_name", fn),
 				zap.Error(err)).
 				WithErrorID("INVALID_FILE_EXTENSION").
-				WithMessage(fmt.Sprintf("File extension %q from file %q is not supported", extStr, fn))
+				WithMessage(fmt.Sprintf(`{"file": %q, "extension": %q}`, fn, extStr))
 		}
 		blobs[i] = &pacta.Blob{
 			FileType: ft,
 			FileName: item.FileName,
 		}
-		resp.Items[i].FileName = string(fn)
+		respItems[i].FileName = string(fn)
 	}
 
 	for i := range request.Body.Items {
@@ -63,7 +65,7 @@ func (s *Server) StartPortfolioUpload(ctx context.Context, request api.StartPort
 			return nil, oapierr.Internal("failed to sign blob URI", zap.String("uri", uri), zap.Error(err))
 		}
 		blobs[i].BlobURI = pacta.BlobURI(uri)
-		resp.Items[i].UploadUrl = signed
+		respItems[i].UploadUrl = signed
 	}
 
 	err = s.DB.Transactional(ctx, func(tx db.Tx) error {
@@ -83,7 +85,7 @@ func (s *Server) StartPortfolioUpload(ctx context.Context, request api.StartPort
 			if err != nil {
 				return fmt.Errorf("creating incomplete upload %d: %w", i, err)
 			}
-			resp.Items[i].IncompleteUploadId = string(iuid)
+			respItems[i].IncompleteUploadId = string(iuid)
 		}
 		return nil
 	})
@@ -91,7 +93,7 @@ func (s *Server) StartPortfolioUpload(ctx context.Context, request api.StartPort
 		return nil, oapierr.Internal("failed to create uploads", zap.Error(err))
 	}
 
-	return resp, nil
+	return api.StartPortfolioUpload200JSONResponse{Items: respItems}, nil
 }
 
 // Called after uploads of portfolios to cloud storage are complete.
@@ -119,7 +121,7 @@ func (s *Server) CompletePortfolioUpload(ctx context.Context, request api.Comple
 		blobIDs := []pacta.BlobID{}
 		for _, id := range ids {
 			iu := ius[id]
-			if iu == nil || iu.Owner.ID != ownerID {
+			if iu == nil || iu.Owner == nil || iu.Owner.ID != ownerID {
 				return oapierr.NotFound(
 					fmt.Sprintf("incomplete upload %s does not belong to user", id),
 					zap.String("incomplete_upload_id", string(id)),