diff --git a/bridge.go b/bridge.go
index 9e1e201..eb2b5d0 100644
--- a/bridge.go
+++ b/bridge.go
@@ -362,6 +362,53 @@ func validateSchemaNode(value any, schema map[string]any, path string) error {
 		}
 	}
 
+	if err := validateSchemaCombinators(value, schema, path); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func validateSchemaCombinators(value any, schema map[string]any, path string) error {
+	if subschemas := schemaObjects(schema["allOf"]); len(subschemas) > 0 {
+		for _, subschema := range subschemas {
+			if err := validateSchemaNode(value, subschema, path); err != nil {
+				return err
+			}
+		}
+	}
+
+	if subschemas := schemaObjects(schema["anyOf"]); len(subschemas) > 0 {
+		for _, subschema := range subschemas {
+			if err := validateSchemaNode(value, subschema, path); err == nil {
+				goto anyOfMatched
+			}
+		}
+		return fmt.Errorf("%s must match at least one schema in anyOf", displayPath(path))
+	}
+
+anyOfMatched:
+	if subschemas := schemaObjects(schema["oneOf"]); len(subschemas) > 0 {
+		matches := 0
+		for _, subschema := range subschemas {
+			if err := validateSchemaNode(value, subschema, path); err == nil {
+				matches++
+			}
+		}
+		if matches != 1 {
+			if matches == 0 {
+				return fmt.Errorf("%s must match exactly one schema in oneOf", displayPath(path))
+			}
+			return fmt.Errorf("%s matches multiple schemas in oneOf", displayPath(path))
+		}
+	}
+
+	if subschema, ok := schema["not"].(map[string]any); ok && subschema != nil {
+		if err := validateSchemaNode(value, subschema, path); err == nil {
+			return fmt.Errorf("%s must not match the forbidden schema", displayPath(path))
+		}
+	}
+
 	return nil
 }
 
@@ -624,6 +671,23 @@ func schemaMap(value any) map[string]any {
 	return m
 }
 
+func schemaObjects(value any) []map[string]any {
+	switch raw := value.(type) {
+	case []any:
+		out := make([]map[string]any, 0, len(raw))
+		for _, item := range raw {
+			if schema := schemaMap(item); schema != nil {
+				out = append(out, schema)
+			}
+		}
+		return out
+	case []map[string]any:
+		return append([]map[string]any(nil), raw...)
+	default:
+		return nil
+	}
+}
+
 func stringList(value any) []string {
 	switch raw := value.(type) {
 	case []any:
diff --git a/bridge_test.go b/bridge_test.go
index baa8e26..706f7eb 100644
--- a/bridge_test.go
+++ b/bridge_test.go
@@ -408,6 +408,109 @@ func TestToolBridge_Bad_RejectsInvalidEnumValues(t *testing.T) {
 	}
 }
 
+func TestToolBridge_Good_ValidatesSchemaCombinators(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	engine := gin.New()
+
+	bridge := api.NewToolBridge("/tools")
+	bridge.Add(api.ToolDescriptor{
+		Name:        "route_choice",
+		Description: "Choose a route",
+		Group:       "items",
+		InputSchema: map[string]any{
+			"type": "object",
+			"properties": map[string]any{
+				"choice": map[string]any{
+					"oneOf": []any{
+						map[string]any{
+							"type": "string",
+							"allOf": []any{
+								map[string]any{"minLength": 2},
+								map[string]any{"pattern": "^[A-Z]+$"},
+							},
+						},
+						map[string]any{
+							"type":    "string",
+							"pattern": "^A",
+						},
+					},
+				},
+			},
+			"required": []any{"choice"},
+		},
+	}, func(c *gin.Context) {
+		c.JSON(http.StatusOK, api.OK("accepted"))
+	})
+
+	rg := engine.Group(bridge.BasePath())
+	bridge.RegisterRoutes(rg)
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodPost, "/tools/route_choice", bytes.NewBufferString(`{"choice":"BC"}`))
+	engine.ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+}
+
+func TestToolBridge_Bad_RejectsAmbiguousOneOfMatches(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	engine := gin.New()
+
+	bridge := api.NewToolBridge("/tools")
+	bridge.Add(api.ToolDescriptor{
+		Name:        "route_choice",
+		Description: "Choose a route",
+		Group:       "items",
+		InputSchema: map[string]any{
+			"type": "object",
+			"properties": map[string]any{
+				"choice": map[string]any{
+					"oneOf": []any{
+						map[string]any{
+							"type": "string",
+							"allOf": []any{
+								map[string]any{"minLength": 1},
+								map[string]any{"pattern": "^[A-Z]+$"},
+							},
+						},
+						map[string]any{
+							"type":    "string",
+							"pattern": "^A",
+						},
+					},
+				},
+			},
+			"required": []any{"choice"},
+		},
+	}, func(c *gin.Context) {
+		c.JSON(http.StatusOK, api.OK("accepted"))
+	})
+
+	rg := engine.Group(bridge.BasePath())
+	bridge.RegisterRoutes(rg)
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodPost, "/tools/route_choice", bytes.NewBufferString(`{"choice":"A"}`))
+	engine.ServeHTTP(w, req)
+
+	if w.Code != http.StatusBadRequest {
+		t.Fatalf("expected 400, got %d", w.Code)
+	}
+
+	var resp api.Response[any]
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("unmarshal error: %v", err)
+	}
+	if resp.Success {
+		t.Fatal("expected Success=false")
+	}
+	if resp.Error == nil || resp.Error.Code != "invalid_request_body" {
+		t.Fatalf("expected invalid_request_body error, got %#v", resp.Error)
+	}
+}
+
 func TestToolBridge_Bad_RejectsAdditionalProperties(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 	engine := gin.New()