diff --git a/go/internal/server/gamedata/pack_detail.go b/go/internal/server/gamedata/pack_detail.go
new file mode 100644
index 0000000..3b119ab
--- /dev/null
+++ b/go/internal/server/gamedata/pack_detail.go
@@ -0,0 +1,67 @@
+package gamedata
+
+import (
+	"database/sql"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// PackDetailDesign identifies the monsters whose state is consumed by the
+// client's PackMapRewardInfo. Ordinary story battle rewards are excluded.
+type PackDetailDesign struct{ RegenMonsterIDs []int }
+
+func LoadPackDetailDesign(root, version string, packID int) (PackDetailDesign, error) {
+	if packID <= 0 {
+		return PackDetailDesign{}, fmt.Errorf("gamedata: invalid detail pack %d", packID)
+	}
+	plain, err := ReadDatabase(root, version, fmt.Sprintf("pack%d", packID))
+	if err != nil {
+		return PackDetailDesign{}, err
+	}
+	dir, err := os.MkdirTemp("", "bd2-pack-detail-")
+	if err != nil {
+		return PackDetailDesign{}, err
+	}
+	defer os.RemoveAll(dir)
+	path := filepath.Join(dir, "pack.db")
+	if err := os.WriteFile(path, plain, 0o600); err != nil {
+		return PackDetailDesign{}, err
+	}
+	db, err := sql.Open("sqlite", "file:"+filepath.ToSlash(path)+"?mode=ro")
+	if err != nil {
+		return PackDetailDesign{}, err
+	}
+	defer db.Close()
+	return loadPackDetailDesign(db)
+}
+
+func loadPackDetailDesign(db *sql.DB) (PackDetailDesign, error) {
+	rows, err := db.Query("SELECT id,ProtoBuf FROM FieldMonsterTable ORDER BY id")
+	if err != nil {
+		return PackDetailDesign{}, err
+	}
+	defer rows.Close()
+	var design PackDetailDesign
+	for rows.Next() {
+		var id int
+		var raw []byte
+		if err := rows.Scan(&id, &raw); err != nil {
+			return PackDetailDesign{}, err
+		}
+		values := map[int]uint64{}
+		for _, field := range []int{24, 30, 31} {
+			v, err := packedInts(raw, field)
+			if err != nil || len(v) > 1 || id <= 0 {
+				return PackDetailDesign{}, fmt.Errorf("gamedata: invalid detail monster %d field %d", id, field)
+			}
+			if len(v) == 1 {
+				values[field] = v[0]
+			}
+		}
+		if values[31] == 1 && values[30] != 3 && values[24] > 0 {
+			design.RegenMonsterIDs = append(design.RegenMonsterIDs, id)
+		}
+	}
+	return design, rows.Err()
+}
diff --git a/go/internal/server/gamedata/pack_detail_test.go b/go/internal/server/gamedata/pack_detail_test.go
new file mode 100644
index 0000000..a149ea9
--- /dev/null
+++ b/go/internal/server/gamedata/pack_detail_test.go
@@ -0,0 +1,34 @@
+package gamedata
+
+import (
+	"bd2server/internal/server/wire"
+	"database/sql"
+	"testing"
+)
+
+func TestPackDetailDesignOnlyIncludesClientRegenRewardCategory(t *testing.T) {
+	db, err := sql.Open("sqlite", ":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if _, err := db.Exec("CREATE TABLE FieldMonsterTable(id INTEGER,ProtoBuf BLOB)"); err != nil {
+		t.Fatal(err)
+	}
+	for _, r := range []struct{ id, regen, typ, skip int }{{1, 0, 0, 0}, {2, 1, 0, 0}, {3, 0, 0, 1}, {4, 1, 3, 1}, {5, 1, 0, 1}, {6, 1, 1, 1}, {7, 1, 0, 2}} {
+		raw := wire.AppendVarint(wire.AppendVarint(wire.AppendVarint(nil, 24, uint64(r.regen)), 30, uint64(r.typ)), 31, uint64(r.skip))
+		if _, err := db.Exec("INSERT INTO FieldMonsterTable VALUES(?,?)", r.id, raw); err != nil {
+			t.Fatal(err)
+		}
+	}
+	design, err := loadPackDetailDesign(db)
+	if err != nil || len(design.RegenMonsterIDs) != 2 || design.RegenMonsterIDs[0] != 5 || design.RegenMonsterIDs[1] != 6 {
+		t.Fatalf("design=%+v err=%v", design, err)
+	}
+	if _, err := db.Exec("INSERT INTO FieldMonsterTable VALUES(8,?)", wire.AppendVarint(wire.AppendVarint(nil, 24, 1), 24, 2)); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := loadPackDetailDesign(db); err == nil {
+		t.Fatal("duplicate scalar accepted")
+	}
+}
diff --git a/go/internal/server/world/pack_detail.go b/go/internal/server/world/pack_detail.go
new file mode 100644
index 0000000..2f1b7e1
--- /dev/null
+++ b/go/internal/server/world/pack_detail.go
@@ -0,0 +1,45 @@
+package world
+
+import (
+	"bd2server/internal/server/gamedata"
+	"bd2server/internal/server/wire"
+	"fmt"
+)
+
+func (s *Service) handlePackDetail(request []byte) (int, []byte, bool, error) {
+	seq, found, err := wire.Varint(request, 1)
+	if err != nil || !found || seq == 0 || seq > 0x7fffffff {
+		return 0, nil, true, fmt.Errorf("%w: PackDetailInfo invalid sequence", ErrInvalidRequest)
+	}
+	packID, err := requestPack(request)
+	if err != nil {
+		return 0, nil, true, err
+	}
+	if !s.packUnlocked(packID) || !s.packSummaryTargets[packID] {
+		return 0, nil, true, fmt.Errorf("%w: PackDetailInfo unavailable pack %d", ErrInvalidRequest, packID)
+	}
+	if s.packDetailDesign == nil {
+		return 0, nil, true, fmt.Errorf("world: missing pack detail design loader")
+	}
+	design, err := s.packDetailDesign(packID)
+	if err != nil {
+		return 0, nil, true, err
+	}
+	if len(design.RegenMonsterIDs) > 0 {
+		// Empty monster state means defeated to the client. Until regeneration
+		// has a persisted domain, do not invent active flags or claim history.
+		return 0, nil, true, fmt.Errorf("%w: PackDetailInfo pack %d requires regenerating monster state", ErrInvalidRequest, packID)
+	}
+	// These repeated fields contain obtained field objects and completed
+	// research objects, not static candidates. No such grants exist in the
+	// current domain. Ordinary story battle inventory grants are excluded by
+	// the GameData monster category verified above. The response's protobuf
+	// collections are non-null even when the payload has no encoded fields.
+	return 627, []byte{}, true, nil
+}
+
+func (s *Service) attachPackDetailDesign(root, version string) {
+	s.packDetailDesign = func(packID int) (gamedata.PackDetailDesign, error) {
+		return gamedata.LoadPackDetailDesign(root, version, packID)
+	}
+}
diff --git a/go/internal/server/world/pack_detail_test.go b/go/internal/server/world/pack_detail_test.go
new file mode 100644
index 0000000..1fa1c04
--- /dev/null
+++ b/go/internal/server/world/pack_detail_test.go
@@ -0,0 +1,60 @@
+package world
+
+import (
+	"bd2server/internal/server/gamedata"
+	"bd2server/internal/server/wire"
+	"errors"
+	"testing"
+)
+
+func TestPackDetailUsesVerifiedDesignAndRejectsUnavailableState(t *testing.T) {
+	s := testService()
+	s.packSummaryTargets = map[int]bool{21: true, 22: true}
+	called := 0
+	s.packDetailDesign = func(id int) (gamedata.PackDetailDesign, error) {
+		called++
+		if id != 21 {
+			t.Fatalf("wrong pack %d", id)
+		}
+		return gamedata.PackDetailDesign{}, nil
+	}
+	request := wire.AppendVarint(wire.AppendVarint(nil, 1, 10), 2, 21)
+	if err := s.state.ClearQuest(1, 21); err != nil {
+		t.Fatal(err)
+	}
+	code, response, handled, err := s.Handle("/PackDetailInfo", request)
+	if err != nil || !handled || code != 627 || response == nil || len(response) != 0 || called != 1 {
+		t.Fatalf("detail code=%d body=%x handled=%v err=%v calls=%d", code, response, handled, err, called)
+	}
+	s.packDetailDesign = func(int) (gamedata.PackDetailDesign, error) {
+		return gamedata.PackDetailDesign{RegenMonsterIDs: []int{101}}, nil
+	}
+	_, _, handled, err = s.Handle("/PackDetailInfo", request)
+	if !handled || !errors.Is(err, ErrInvalidRequest) {
+		t.Fatalf("unsupported regeneration handled=%v err=%v", handled, err)
+	}
+	s.packDetailDesign = func(int) (gamedata.PackDetailDesign, error) {
+		return gamedata.PackDetailDesign{}, errors.New("missing design")
+	}
+	if _, _, _, err := s.Handle("/PackDetailInfo", request); err == nil {
+		t.Fatal("design failure swallowed")
+	}
+}
+
+func TestPackDetailRejectsInvalidAndLockedRequestsBeforeReadingDesign(t *testing.T) {
+	s := testService()
+	s.packSummaryTargets = map[int]bool{21: true, 22: true}
+	s.packDetailDesign = func(int) (gamedata.PackDetailDesign, error) {
+		t.Fatal("invalid request read GameData")
+		return gamedata.PackDetailDesign{}, nil
+	}
+	for _, request := range [][]byte{nil, {8}, wire.AppendVarint(nil, 1, 1), wire.AppendVarint(wire.AppendVarint(nil, 1, 1), 2, 22), wire.AppendVarint(wire.AppendVarint(nil, 1, 0x80000000), 2, 21)} {
+		if _, _, handled, err := s.Handle("/PackDetailInfo", request); !handled || err == nil {
+			t.Fatalf("request %x handled=%v err=%v", request, handled, err)
+		}
+	}
+	delete(s.packSummaryTargets, 21)
+	if _, _, _, err := s.Handle("/PackDetailInfo", wire.AppendVarint(wire.AppendVarint(nil, 1, 1), 2, 21)); err == nil {
+		t.Fatal("non-target pack accepted")
+	}
+}
diff --git a/go/internal/server/world/world.go b/go/internal/server/world/world.go
index f7dfa40..5c8b8d7 100644
--- a/go/internal/server/world/world.go
+++ b/go/internal/server/world/world.go
@@ -85,6 +85,7 @@ func Load(seedPath, gameDataRoot, gameDataVersion string, storage stateio.Store,
 	}
 	service := &Service{seed: seed, state: state, starter: starter, equipment: equipment, inventory: inventory, wallet: wallet, characters: characters, quests: quests, transition: transition, packs: packs, transitions: transitions, activePack: activePack, fieldPacks: fieldPacks}
 	service.packSummaryTargets = packSummaryTargets
+	service.attachPackDetailDesign(gameDataRoot, gameDataVersion)
 	return service, nil
 }
 
@@ -118,6 +119,7 @@ func (s *Service) setCurrentPack(packID int) {
 }
 
 type Service struct {
+	packDetailDesign   func(int) (gamedata.PackDetailDesign, error)
 	packSummaryTargets map[int]bool
 	fieldPacks         map[int]gamedata.FieldPack
 	squadLevel         func() (uint64, error)
@@ -156,6 +158,8 @@ func (s *Service) AttachDecks(decks *deck.Store) error {
 
 func (s *Service) Handle(path string, request []byte) (int, []byte, bool, error) {
 	switch path {
+	case "/PackDetailInfo":
+		return s.handlePackDetail(request)
 	case "/PackSummaryInfoList":
 		return s.handlePackSummary(request)
 	case "/PackInfo":