Return error type for unknown tools in inventory builder and handle it in HTTP handler

Author: omgitsads

pkg/http/handler.go

@@ -2,6 +2,7 @@ package http
 
 import (
 	"context"
+	"errors"
 	"log/slog"
 	"net/http"
 
@@ -178,6 +179,12 @@ func withInsiders(next http.Handler) http.Handler {
 func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	inv, err := h.inventoryFactoryFunc(r)
 	if err != nil {
+		if errors.Is(err, inventory.UnknownToolsErr) {
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(err.Error()))
+			return
+		}
+
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}

pkg/inventory/builder.go

@@ -2,11 +2,16 @@ package inventory
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"sort"
 	"strings"
 )
 
+var (
+	UnknownToolsErr = errors.New("unknown tools specified in WithTools")
+)
+
 // ToolFilter is a function that determines if a tool should be included.
 // Returns true if the tool should be included, false to exclude it.
 type ToolFilter func(ctx context.Context, tool *ServerTool) (bool, error)
@@ -204,7 +209,7 @@ func (b *Builder) Build() (*Inventory, error) {
 
 		// Error out if there are unrecognized tools
 		if len(unrecognizedTools) > 0 {
-			return nil, fmt.Errorf("unrecognized tools: %s", strings.Join(unrecognizedTools, ", "))
+			return nil, fmt.Errorf("%w: %s", UnknownToolsErr, strings.Join(unrecognizedTools, ", "))
 		}
 	}