http and common

cmd/backoffice/main.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"errors"
 	"log"
 	"net/http"
 	"os"
@@ -10,6 +9,8 @@ import (
 
 	"git.k6n.net/mats/go-cart-actor/pkg/backofficeadmin"
 	"git.k6n.net/mats/platform/config"
+	"git.k6n.net/mats/platform/httpclient"
+	"git.k6n.net/mats/platform/httpserver"
 	"git.k6n.net/mats/platform/rabbit"
 )
 
@@ -41,21 +42,14 @@ func main() {
 	})
 
 	// Global CORS middleware allowing all origins and handling preflight.
-	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Access-Control-Allow-Origin", "*")
-		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
-		w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization, X-Requested-With")
-		w.Header().Set("Access-Control-Expose-Headers", "*")
-		if r.Method == http.MethodOptions {
-			w.WriteHeader(http.StatusNoContent)
-			return
-		}
-		mux.ServeHTTP(w, r)
-	})
-
 	srv := &http.Server{
-		Addr:         addr,
-		Handler:      handler,
+		Addr: addr,
+		Handler: httpclient.CORS(
+			httpclient.WithOrigin("*"),
+			httpclient.WithMethods("GET, POST, PUT, PATCH, DELETE, OPTIONS"),
+			httpclient.WithHeaders("Content-Type, Authorization, X-Requested-With"),
+			httpclient.WithExposeHeaders("*"),
+		)(mux),
 		ReadTimeout:  15 * time.Second,
 		WriteTimeout: 30 * time.Second,
 		IdleTimeout:  60 * time.Second,
@@ -70,6 +64,7 @@ func main() {
 		if err != nil {
 			log.Fatalf("failed to connect to RabbitMQ: %v", err)
 		}
+		defer conn.Close()
 	}
 	if err := app.Start(ctx, conn); err != nil {
 		log.Printf("AMQP listener disabled: %v", err)
@@ -78,7 +73,9 @@ func main() {
 	}
 
 	log.Printf("backoffice HTTP listening on %s", addr)
-	if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
-		log.Fatalf("http server error: %v", err)
+	if err := httpserver.RunServerWithShutdown(srv, "cart-backoffice", 10*time.Second, 5*time.Second,
+		func(context.Context) error { cancel(); return nil },
+	); err != nil {
+		log.Fatalf("server: %v", err)
 	}
 }

cmd/cart/main.go

@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
-	"net"
 	"net/http"
 	"net/http/pprof"
 	"os"
@@ -26,6 +25,7 @@ import (
 	"git.k6n.net/mats/platform/catalog"
 	"git.k6n.net/mats/platform/config"
 	"git.k6n.net/mats/platform/event"
+	"git.k6n.net/mats/platform/httpserver"
 	"git.k6n.net/mats/platform/rabbit"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/redis/go-redis/v9"
@@ -524,9 +524,11 @@ func main() {
 	httpAddr := normalizeListenAddr(cartPort)
 	debugAddr := normalizeListenAddr(config.EnvString("CART_DEBUG_PORT", "8081"))
 
+	// Debug mux on separate port (metrics + pprof).
+	go http.ListenAndServe(debugAddr, debugMux)
+
 	srv := &http.Server{
 		Addr:        httpAddr,
-		BaseContext: func(net.Listener) context.Context { return ctx },
 		ReadTimeout: 10 * time.Second,
 		// Close idle keep-alive connections so a load test with many short-lived
 		// clients doesn't pin file handles open indefinitely.
@@ -535,38 +537,15 @@ func main() {
 		Handler:      otelhttp.NewHandler(mux, "/"),
 	}
 
-	defer func() {
-
-		fmt.Println("Shutting down due to signal")
-		otelShutdown(context.Background())
-		diskStorage.Close()
-		pool.Close()
-
-	}()
-
-	srvErr := make(chan error, 1)
-	go func() {
-		srvErr <- srv.ListenAndServe()
-	}()
-
-	// Inventory change consumption used to live here over the bare Redis
-	// `inventory_changed` channel; it is now owned by the cart-inventory
-	// service, which translates quantity changes into inventory.level_changed
-	// bus crossings. The cart reads exact stock synchronously when it needs it.
-	// See docs/inventory-shape.md.
-
 	log.Printf("Server started at %s (debug %s)", httpAddr, debugAddr)
 
-	go http.ListenAndServe(debugAddr, debugMux)
-
-	select {
-	case err = <-srvErr:
-		// Error when starting HTTP server.
-		log.Fatalf("Unable to start server: %v", err)
-	case <-ctx.Done():
-		// Wait for first CTRL+C.
-		// Stop receiving signal notifications as soon as possible.
-		stop()
+	if err := httpserver.RunServerWithShutdown(srv, "cart", 15*time.Second, 5*time.Second,
+		func(context.Context) error { stop(); return nil },
+		func(context.Context) error { otelShutdown(context.Background()); return nil },
+		func(context.Context) error { diskStorage.Close(); return nil },
+		func(context.Context) error { pool.Close(); return nil },
+	); err != nil {
+		log.Fatalf("server: %v", err)
 	}
 
 }

cmd/cart/utils.go

@@ -55,14 +55,6 @@ func getOriginalHost(r *http.Request) string {
 	return r.Host
 }
 
-func getClientIp(r *http.Request) string {
-	ip := r.Header.Get("X-Forwarded-For")
-	if ip == "" {
-		ip = r.RemoteAddr
-	}
-	return ip
-}
-
 func CookieCartIdHandler(fn func(cartId cart.CartId, w http.ResponseWriter, r *http.Request) error) func(w http.ResponseWriter, r *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
 

cmd/checkout/checkout_builder.go

@@ -9,6 +9,7 @@ import (
 
 	"git.k6n.net/mats/go-cart-actor/pkg/cart"
 	"git.k6n.net/mats/go-cart-actor/pkg/checkout"
+	"git.k6n.net/mats/platform/httpclient"
 	"git.k6n.net/mats/platform/tax"
 	adyenCheckout "github.com/adyen/adyen-go-api-library/v21/src/checkout"
 	"github.com/adyen/adyen-go-api-library/v21/src/common"
@@ -233,7 +234,7 @@ func GetCheckoutMetaFromRequest(r *http.Request) *CheckoutMeta {
 		siteUrl = checkoutPublicURL
 	}
 	return &CheckoutMeta{
-		ClientIp:        getClientIp(r),
+		ClientIp:        httpclient.ClientIP(r),
 		SiteUrl:         siteUrl,
 		CallbackBaseUrl: checkoutCallbackBaseURL,
 		Country:         country,

cmd/checkout/main.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"log"
-	"net"
 	"net/http"
 	"os"
 	"os/signal"
@@ -17,6 +16,7 @@ import (
 	"git.k6n.net/mats/go-cart-actor/pkg/telemetry"
 	redisinv "git.k6n.net/mats/go-redis-inventory/pkg/inventory"
 	"git.k6n.net/mats/platform/config"
+	"git.k6n.net/mats/platform/httpserver"
 	"git.k6n.net/mats/platform/rabbit"
 	"git.k6n.net/mats/platform/tax"
 	"github.com/adyen/adyen-go-api-library/v21/src/adyen"
@@ -293,35 +293,25 @@ func main() {
 		w.Write([]byte("1.0.0"))
 	})
 
+	// Debug mux on separate port (metrics + pprof).
+	go http.ListenAndServe(":8081", debugMux)
+
 	srv := &http.Server{
 		Addr:         ":8080",
-		BaseContext:  func(net.Listener) context.Context { return ctx },
 		ReadTimeout:  10 * time.Second,
 		WriteTimeout: 20 * time.Second,
 		Handler:      otelhttp.NewHandler(mux, "/"),
 	}
 
-	defer func() {
-		fmt.Println("Shutting down due to signal")
-		otelShutdown(context.Background())
-		diskStorage.Close()
-		pool.Close()
-	}()
-
-	srvErr := make(chan error, 1)
-	go func() {
-		srvErr <- srv.ListenAndServe()
-	}()
-
 	log.Print("Checkout server started at port 8080")
 
-	go http.ListenAndServe(":8081", debugMux)
-
-	select {
-	case err = <-srvErr:
-		log.Fatalf("Unable to start server: %v", err)
-	case <-ctx.Done():
-		stop()
+	if err := httpserver.RunServerWithShutdown(srv, "checkout", 15*time.Second, 5*time.Second,
+		func(context.Context) error { stop(); return nil },
+		func(context.Context) error { otelShutdown(context.Background()); return nil },
+		func(context.Context) error { diskStorage.Close(); return nil },
+		func(context.Context) error { pool.Close(); return nil },
+	); err != nil {
+		log.Fatalf("server: %v", err)
 	}
 }
 

cmd/checkout/utils.go

@@ -36,14 +36,6 @@ func getScheme(r *http.Request) string {
 	return "https"
 }
 
-func getClientIp(r *http.Request) string {
-	ip := r.Header.Get("X-Forwarded-For")
-	if ip == "" {
-		ip = r.RemoteAddr
-	}
-	return ip
-}
-
 func getCurrency(country string) string {
 	if country == "no" {
 		return "NOK"

cmd/profile/main.go

@@ -4,9 +4,7 @@ import (
 	"context"
 	"crypto/rand"
 	"encoding/hex"
-	"fmt"
 	"log"
-	"net"
 	"net/http"
 	"net/mail"
 	"os"
@@ -22,6 +20,7 @@ import (
 	"git.k6n.net/mats/go-cart-actor/pkg/proxy"
 	"git.k6n.net/mats/go-cart-actor/pkg/telemetry"
 	"git.k6n.net/mats/platform/config"
+	"git.k6n.net/mats/platform/httpserver"
 	"git.k6n.net/mats/platform/rabbit"
 	"github.com/redis/go-redis/v9"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
@@ -311,35 +310,25 @@ func main() {
 		w.Write([]byte("1.0.0"))
 	})
 
+	// Debug mux on separate port (metrics + pprof).
+	go http.ListenAndServe(":8081", debugMux)
+
 	srv := &http.Server{
 		Addr:         config.EnvString("PROFILE_ADDR", ":8080"),
-		BaseContext:  func(net.Listener) context.Context { return ctx },
 		ReadTimeout:  10 * time.Second,
 		WriteTimeout: 20 * time.Second,
 		Handler:      otelhttp.NewHandler(mux, "/"),
 	}
 
-	defer func() {
-		fmt.Println("Shutting down profile service")
-		otelShutdown(context.Background())
-		diskStorage.Close()
-		pool.Close()
-	}()
-
-	srvErr := make(chan error, 1)
-	go func() {
-		srvErr <- srv.ListenAndServe()
-	}()
-
 	log.Print("Profile server started at port 8080")
 
-	go http.ListenAndServe(":8081", debugMux)
-
-	select {
-	case err = <-srvErr:
-		log.Fatalf("Unable to start server: %v", err)
-	case <-ctx.Done():
-		stop()
+	if err := httpserver.RunServerWithShutdown(srv, "profile", 15*time.Second, 5*time.Second,
+		func(context.Context) error { stop(); return nil },
+		func(context.Context) error { otelShutdown(context.Background()); return nil },
+		func(context.Context) error { diskStorage.Close(); return nil },
+		func(context.Context) error { pool.Close(); return nil },
+	); err != nil {
+		log.Fatalf("server: %v", err)
 	}
 }
 

pkg/promotions/mcp/public.go

@@ -25,151 +25,167 @@ func NewPublic(store *promotions.Store, eval *promotions.PromotionService) *Serv
 
 func (s *Server) buildPublicTools() []pmcp.Tool {
 	return []pmcp.Tool{
-		{
-			Name:        "list_promotions",
-			Description: "List all promotion rules the cart engine evaluates, optionally filtered by status (active|inactive|scheduled|expired).",
-			InputSchema: pmcp.Object(pmcp.Props{
-				"status": pmcp.String("optional status filter: active|inactive|scheduled|expired"),
-			}, nil),
-			Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
-				var a struct {
-					Status string `json:"status"`
-				}
-				if err := pmcp.Decode(args, &a); err != nil {
-					return nil, err
-				}
-				rules := s.store.List()
-				if a.Status != "" {
-					filtered := rules[:0:0]
-					for _, r := range rules {
-						if string(r.Status) == a.Status {
-							filtered = append(filtered, r)
-						}
-					}
-					rules = filtered
-				}
-				return map[string]any{"promotions": rules, "count": len(rules)}, nil
-			},
-		},
-		{
-			Name:        "get_promotion",
-			Description: "Fetch a single promotion rule by id.",
-			InputSchema: pmcp.Object(pmcp.Props{"id": pmcp.String("the promotion id")}, []string{"id"}),
-			Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
-				var a struct {
-					ID string `json:"id"`
-				}
-				if err := pmcp.Decode(args, &a); err != nil {
-					return nil, err
-				}
-				r, ok := s.store.Get(a.ID)
-				if !ok {
-					return nil, fmt.Errorf("promotion %q not found", a.ID)
-				}
-				return r, nil
-			},
-		},
-		{
-			Name: "preview_cart_discount",
-			Description: "Evaluate the current active promotions against a hypothetical cart total and report the " +
-				"matched discount. cartTotalIncVat is in öre incl. VAT (e.g. 5 000 000 = 50 000 kr). Useful for " +
-				"verifying Volymrabatt tiers without touching a real cart.",
-			InputSchema: pmcp.Object(pmcp.Props{
-				"cartTotalIncVat": pmcp.Integer("cart total incl. VAT, in öre"),
-				"itemQuantity":    pmcp.Integer("optional total item quantity"),
-				"customerSegment": pmcp.String("optional customer segment"),
-			}, []string{"cartTotalIncVat"}),
-			Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
-				var a struct {
-					CartTotalIncVat int64  `json:"cartTotalIncVat"`
-					ItemQuantity    int    `json:"itemQuantity"`
-					CustomerSegment string `json:"customerSegment"`
-				}
-				if err := pmcp.Decode(args, &a); err != nil {
-					return nil, err
-				}
-				g := syntheticCart(a.CartTotalIncVat, a.ItemQuantity, s.defaultVatRate())
-				opts := []promotions.ContextOption{promotions.WithNow(time.Now())}
-				if a.CustomerSegment != "" {
-					opts = append(opts, promotions.WithCustomerSegment(a.CustomerSegment))
-				}
-				ctx := promotions.NewContextFromCart(g, opts...)
-				results, actions := s.eval.EvaluateAll(s.store.Snapshot(), ctx)
-				s.eval.ApplyResults(g, results, ctx)
-				return map[string]any{
-					"subtotalIncVat":    a.CartTotalIncVat,
-					"discountIncVat":    g.TotalDiscount.IncVat,
-					"netIncVat":         g.TotalPrice.IncVat,
-					"matchedActions":    actions,
-					"appliedPromotions": g.AppliedPromotions,
-				}, nil
-			},
-		},
-		{
-			Name: "evaluate_promotion",
-			Description: "Evaluate promotions against a hypothetical cart and return the full evaluation result: " +
-				"which promotions match, what discount they apply, and any pending next-tier nudges (\"spend X more for Y%\"). " +
-				"When promotionId is set, only that specific promotion is evaluated (useful for testing a new rule). " +
-				"When omitted, all active promotions are evaluated. cartTotalIncVat is in öre incl. VAT.",
-			InputSchema: pmcp.Object(pmcp.Props{
-				"cartTotalIncVat": pmcp.Integer("cart total incl. VAT, in öre"),
-				"promotionId":     pmcp.String("optional: evaluate only this promotion (by id)"),
-				"itemQuantity":    pmcp.Integer("optional total item quantity"),
-				"customerSegment": pmcp.String("optional customer segment"),
-			}, []string{"cartTotalIncVat"}),
-			Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
-				var a struct {
-					CartTotalIncVat int64  `json:"cartTotalIncVat"`
-					PromotionId     string `json:"promotionId"`
-					ItemQuantity    int    `json:"itemQuantity"`
-					CustomerSegment string `json:"customerSegment"`
-				}
-				if err := pmcp.Decode(args, &a); err != nil {
-					return nil, err
-				}
+		s.toolListPromotions(),
+		s.toolGetPromotion(),
+		s.toolPreviewCartDiscount(),
+		s.toolEvaluatePromotion(),
+	}
+}
 
-				rules := s.store.Snapshot()
-				if a.PromotionId != "" {
-					filtered := rules[:0:0]
-					for _, r := range rules {
-						if r.ID == a.PromotionId {
-							filtered = append(filtered, r)
-							break
-						}
+func (s *Server) toolListPromotions() pmcp.Tool {
+	return pmcp.Tool{
+		Name:        "list_promotions",
+		Description: "List all promotion rules the cart engine evaluates, optionally filtered by status (active|inactive|scheduled|expired).",
+		InputSchema: pmcp.Object(pmcp.Props{
+			"status": pmcp.String("optional status filter: active|inactive|scheduled|expired"),
+		}, nil),
+		Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
+			var a struct {
+				Status string `json:"status"`
+			}
+			if err := pmcp.Decode(args, &a); err != nil {
+				return nil, err
+			}
+			rules := s.store.List()
+			if a.Status != "" {
+				filtered := rules[:0:0]
+				for _, r := range rules {
+					if string(r.Status) == a.Status {
+						filtered = append(filtered, r)
 					}
-					if len(filtered) == 0 {
-						return nil, fmt.Errorf("promotion %q not found", a.PromotionId)
-					}
-					rules = filtered
 				}
+				rules = filtered
+			}
+			return map[string]any{"promotions": rules, "count": len(rules)}, nil
+		},
+	}
+}
 
-				g := syntheticCart(a.CartTotalIncVat, a.ItemQuantity, s.defaultVatRate())
-				opts := []promotions.ContextOption{promotions.WithNow(time.Now())}
-				if a.CustomerSegment != "" {
-					opts = append(opts, promotions.WithCustomerSegment(a.CustomerSegment))
+func (s *Server) toolGetPromotion() pmcp.Tool {
+	return pmcp.Tool{
+		Name:        "get_promotion",
+		Description: "Fetch a single promotion rule by id.",
+		InputSchema: pmcp.Object(pmcp.Props{"id": pmcp.String("the promotion id")}, []string{"id"}),
+		Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
+			var a struct {
+				ID string `json:"id"`
+			}
+			if err := pmcp.Decode(args, &a); err != nil {
+				return nil, err
+			}
+			r, ok := s.store.Get(a.ID)
+			if !ok {
+				return nil, fmt.Errorf("promotion %q not found", a.ID)
+			}
+			return r, nil
+		},
+	}
+}
+
+func (s *Server) toolPreviewCartDiscount() pmcp.Tool {
+	return pmcp.Tool{
+		Name: "preview_cart_discount",
+		Description: "Evaluate the current active promotions against a hypothetical cart total and report the " +
+			"matched discount. cartTotalIncVat is in öre incl. VAT (e.g. 5 000 000 = 50 000 kr). Useful for " +
+			"verifying Volymrabatt tiers without touching a real cart.",
+		InputSchema: pmcp.Object(pmcp.Props{
+			"cartTotalIncVat": pmcp.Integer("cart total incl. VAT, in öre"),
+			"itemQuantity":    pmcp.Integer("optional total item quantity"),
+			"customerSegment": pmcp.String("optional customer segment"),
+		}, []string{"cartTotalIncVat"}),
+		Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
+			var a struct {
+				CartTotalIncVat int64  `json:"cartTotalIncVat"`
+				ItemQuantity    int    `json:"itemQuantity"`
+				CustomerSegment string `json:"customerSegment"`
+			}
+			if err := pmcp.Decode(args, &a); err != nil {
+				return nil, err
+			}
+			g := syntheticCart(a.CartTotalIncVat, a.ItemQuantity, s.defaultVatRate())
+			opts := []promotions.ContextOption{promotions.WithNow(time.Now())}
+			if a.CustomerSegment != "" {
+				opts = append(opts, promotions.WithCustomerSegment(a.CustomerSegment))
+			}
+			ctx := promotions.NewContextFromCart(g, opts...)
+			results, actions := s.eval.EvaluateAll(s.store.Snapshot(), ctx)
+			s.eval.ApplyResults(g, results, ctx)
+			return map[string]any{
+				"subtotalIncVat":    a.CartTotalIncVat,
+				"discountIncVat":    g.TotalDiscount.IncVat,
+				"netIncVat":         g.TotalPrice.IncVat,
+				"matchedActions":    actions,
+				"appliedPromotions": g.AppliedPromotions,
+			}, nil
+		},
+	}
+}
+
+func (s *Server) toolEvaluatePromotion() pmcp.Tool {
+	return pmcp.Tool{
+		Name: "evaluate_promotion",
+		Description: "Evaluate promotions against a hypothetical cart and return the full evaluation result: " +
+			"which promotions match, what discount they apply, and any pending next-tier nudges (\"spend X more for Y%\"). " +
+			"When promotionId is set, only that specific promotion is evaluated (useful for testing a new rule). " +
+			"When omitted, all active promotions are evaluated. cartTotalIncVat is in öre incl. VAT.",
+		InputSchema: pmcp.Object(pmcp.Props{
+			"cartTotalIncVat": pmcp.Integer("cart total incl. VAT, in öre"),
+			"promotionId":     pmcp.String("optional: evaluate only this promotion (by id)"),
+			"itemQuantity":    pmcp.Integer("optional total item quantity"),
+			"customerSegment": pmcp.String("optional customer segment"),
+		}, []string{"cartTotalIncVat"}),
+		Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
+			var a struct {
+				CartTotalIncVat int64  `json:"cartTotalIncVat"`
+				PromotionId     string `json:"promotionId"`
+				ItemQuantity    int    `json:"itemQuantity"`
+				CustomerSegment string `json:"customerSegment"`
+			}
+			if err := pmcp.Decode(args, &a); err != nil {
+				return nil, err
+			}
+
+			rules := s.store.Snapshot()
+			if a.PromotionId != "" {
+				filtered := rules[:0:0]
+				for _, r := range rules {
+					if r.ID == a.PromotionId {
+						filtered = append(filtered, r)
+						break
+					}
 				}
-				ctx := promotions.NewContextFromCart(g, opts...)
-				results, actions := s.eval.EvaluateAll(rules, ctx)
-				evalResults := make([]map[string]any, 0, len(results))
-				for _, r := range results {
-					evalResults = append(evalResults, map[string]any{
-						"ruleId":         r.Rule.ID,
-						"name":           r.Rule.Name,
-						"applicable":     r.Applicable,
-						"failedReason":   r.FailedReason,
-						"matchedActions": r.MatchedActions,
-					})
+				if len(filtered) == 0 {
+					return nil, fmt.Errorf("promotion %q not found", a.PromotionId)
 				}
-				s.eval.ApplyResults(g, results, ctx)
-				return map[string]any{
-					"subtotalIncVat":    a.CartTotalIncVat,
-					"discountIncVat":    g.TotalDiscount.IncVat,
-					"netIncVat":         g.TotalPrice.IncVat,
-					"matchedActions":    actions,
-					"appliedPromotions": g.AppliedPromotions,
-					"evaluationResults": evalResults,
-				}, nil
-			},
+				rules = filtered
+			}
+
+			g := syntheticCart(a.CartTotalIncVat, a.ItemQuantity, s.defaultVatRate())
+			opts := []promotions.ContextOption{promotions.WithNow(time.Now())}
+			if a.CustomerSegment != "" {
+				opts = append(opts, promotions.WithCustomerSegment(a.CustomerSegment))
+			}
+			ctx := promotions.NewContextFromCart(g, opts...)
+			results, actions := s.eval.EvaluateAll(rules, ctx)
+			evalResults := make([]map[string]any, 0, len(results))
+			for _, r := range results {
+				evalResults = append(evalResults, map[string]any{
+					"ruleId":         r.Rule.ID,
+					"name":           r.Rule.Name,
+					"applicable":     r.Applicable,
+					"failedReason":   r.FailedReason,
+					"matchedActions": r.MatchedActions,
+				})
+			}
+			s.eval.ApplyResults(g, results, ctx)
+			return map[string]any{
+				"subtotalIncVat":    a.CartTotalIncVat,
+				"discountIncVat":    g.TotalDiscount.IncVat,
+				"netIncVat":         g.TotalPrice.IncVat,
+				"matchedActions":    actions,
+				"appliedPromotions": g.AppliedPromotions,
+				"evaluationResults": evalResults,
+			}, nil
 		},
 	}
 }

pkg/promotions/mcp/tools.go

@@ -16,50 +16,8 @@ import (
 // and the handler that runs it.
 func (s *Server) buildTools() []pmcp.Tool {
 	return []pmcp.Tool{
-		{
-			Name:        "list_promotions",
-			Description: "List all promotion rules the cart engine evaluates, optionally filtered by status (active|inactive|scheduled|expired).",
-			InputSchema: pmcp.Object(pmcp.Props{
-				"status": pmcp.String("optional status filter: active|inactive|scheduled|expired"),
-			}, nil),
-			Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
-				var a struct {
-					Status string `json:"status"`
-				}
-				if err := pmcp.Decode(args, &a); err != nil {
-					return nil, err
-				}
-				rules := s.store.List()
-				if a.Status != "" {
-					filtered := rules[:0:0]
-					for _, r := range rules {
-						if string(r.Status) == a.Status {
-							filtered = append(filtered, r)
-						}
-					}
-					rules = filtered
-				}
-				return map[string]any{"promotions": rules, "count": len(rules)}, nil
-			},
-		},
-		{
-			Name:        "get_promotion",
-			Description: "Fetch a single promotion rule by id.",
-			InputSchema: pmcp.Object(pmcp.Props{"id": pmcp.String("the promotion id")}, []string{"id"}),
-			Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
-				var a struct {
-					ID string `json:"id"`
-				}
-				if err := pmcp.Decode(args, &a); err != nil {
-					return nil, err
-				}
-				r, ok := s.store.Get(a.ID)
-				if !ok {
-					return nil, fmt.Errorf("promotion %q not found", a.ID)
-				}
-				return r, nil
-			},
-		},
+		s.toolListPromotions(),
+		s.toolGetPromotion(),
 		{
 			Name: "upsert_promotion",
 			Description: "Create a promotion or replace the existing one with the same id. " +
@@ -142,42 +100,7 @@ func (s *Server) buildTools() []pmcp.Tool {
 				return map[string]any{"id": a.ID, "deleted": true}, nil
 			},
 		},
-		{
-			Name: "preview_cart_discount",
-			Description: "Evaluate the current active promotions against a hypothetical cart total and report the " +
-				"matched discount. cartTotalIncVat is in öre incl. VAT (e.g. 5 000 000 = 50 000 kr). Useful for " +
-				"verifying Volymrabatt tiers without touching a real cart.",
-			InputSchema: pmcp.Object(pmcp.Props{
-				"cartTotalIncVat": pmcp.Integer("cart total incl. VAT, in öre"),
-				"itemQuantity":    pmcp.Integer("optional total item quantity"),
-				"customerSegment": pmcp.String("optional customer segment"),
-			}, []string{"cartTotalIncVat"}),
-			Invoke: func(_ context.Context, args json.RawMessage) (any, error) {
-				var a struct {
-					CartTotalIncVat int64  `json:"cartTotalIncVat"`
-					ItemQuantity    int    `json:"itemQuantity"`
-					CustomerSegment string `json:"customerSegment"`
-				}
-				if err := pmcp.Decode(args, &a); err != nil {
-					return nil, err
-				}
-				g := syntheticCart(a.CartTotalIncVat, a.ItemQuantity, s.defaultVatRate())
-				opts := []promotions.ContextOption{promotions.WithNow(time.Now())}
-				if a.CustomerSegment != "" {
-					opts = append(opts, promotions.WithCustomerSegment(a.CustomerSegment))
-				}
-				ctx := promotions.NewContextFromCart(g, opts...)
-				results, actions := s.eval.EvaluateAll(s.store.Snapshot(), ctx)
-				s.eval.ApplyResults(g, results, ctx)
-				return map[string]any{
-					"subtotalIncVat":    a.CartTotalIncVat,
-					"discountIncVat":    g.TotalDiscount.IncVat,
-					"netIncVat":         g.TotalPrice.IncVat,
-					"matchedActions":    actions,
-					"appliedPromotions": g.AppliedPromotions,
-				}, nil
-			},
-		},
+		s.toolPreviewCartDiscount(),
 	}
 }