1 files changed, 80 insertions, 0 deletions
diff --git a/internal/game/core_startup.go b/internal/game/core_startup.go
index 323e519..2e81eac 100644
--- a/internal/game/core_startup.go
+++ b/internal/game/core_startup.go
@@ -27,6 +27,7 @@ func (g *Game) ValidateStartup() []StartupIssue {
 	issues = append(issues, validateIDs(g.DataDir, "drops", "drop table")...)
 	issues = append(issues, validateIDs(g.DataDir, "courses", "course")...)
 	issues = append(issues, validateIDs(g.DataDir, "modules", "module")...)
+	issues = append(issues, validateIDs(g.DataDir, "techs", "tech")...)
 	issues = append(issues, validateIDs(g.DataDir, "help", "help topic")...)
 
 	issues = append(issues, validateRooms(g)...)
@@ -37,6 +38,7 @@ func (g *Game) ValidateStartup() []StartupIssue {
 	issues = append(issues, validateCraftBlocks(g)...)
 	issues = append(issues, validateDropTables(g)...)
 	issues = append(issues, validateCourses(g)...)
+	issues = append(issues, validateTechs(g)...)
 	issues = append(issues, validateRoomWiring(g)...)
 
 	return issues
@@ -747,6 +749,84 @@ func validateNodeAction(prefix string, na *action.NodeAction, itemIDs map[string
 	return issues
 }
 
+var knownTechCategories = map[string]bool{
+	"accuracy":   true,
+	"strength":   true,
+	"defense":    true,
+	"ranged":     true,
+	"science":    true,
+	"protection": true,
+	"utility":    true,
+	"combo":      true,
+}
+
+// Reserved tech IDs whose semantics are coupled to code logic —
+// damageAfterTechProtection maps attack types to protect_melee/ranged/science
+// and killPlayer checks for retribution. These IDs must exist in YAML.
+var reservedTechIDs = map[string]bool{
+	"protect_melee":   true,
+	"protect_ranged":  true,
+	"protect_science": true,
+	"retribution":     true,
+}
+
+func validateTechs(g *Game) []StartupIssue {
+	var issues []StartupIssue
+	seen := make(map[string]bool)
+	for _, def := range AllTechs {
+		if def.ID == "" {
+			issues = append(issues, StartupIssue{
+				Level:   "ERROR",
+				Type:    "reference",
+				Message: "Tech has empty id",
+			})
+			continue
+		}
+		if seen[def.ID] {
+			issues = append(issues, StartupIssue{
+				Level:   "ERROR",
+				Type:    "duplicate",
+				Message: fmt.Sprintf("Duplicate tech %q", def.ID),
+			})
+		}
+		seen[def.ID] = true
+
+		if def.Name == "" {
+			issues = append(issues, StartupIssue{
+				Level:   "WARN",
+				Type:    "reference",
+				Message: fmt.Sprintf("Tech %q: has no name", def.ID),
+			})
+		}
+		if def.Category != "" && !knownTechCategories[def.Category] {
+			issues = append(issues, StartupIssue{
+				Level:   "WARN",
+				Type:    "reference",
+				Message: fmt.Sprintf("Tech %q: unknown category %q", def.ID, def.Category),
+			})
+		}
+		if def.DrainRate < 0 {
+			issues = append(issues, StartupIssue{
+				Level:   "ERROR",
+				Type:    "reference",
+				Message: fmt.Sprintf("Tech %q: negative drain_rate %.2f", def.ID, def.DrainRate),
+			})
+		}
+	}
+
+	for id := range reservedTechIDs {
+		if _, ok := techByID[id]; !ok {
+			issues = append(issues, StartupIssue{
+				Level:   "ERROR",
+				Type:    "reference",
+				Message: fmt.Sprintf("Reserved tech %q does not exist — required by code (damage protection / retribution)", id),
+			})
+		}
+	}
+
+	return issues
+}
+
 func dropTableIDSet(dataDir string) map[string]bool {
 	dir := filepath.Join(dataDir, "drops")
 	ids := make(map[string]bool)