diff --git a/pkg/parser/schema_test.go b/pkg/parser/schema_test.go
index c2257ae482f..0ce13d1ebf8 100644
--- a/pkg/parser/schema_test.go
+++ b/pkg/parser/schema_test.go
@@ -621,6 +621,45 @@ func TestValidateMainWorkflowFrontmatterWithSchema(t *testing.T) {
 			wantErr:     true,
 			errContains: "minItems: got 0, want 1",
 		},
+		{
+			name: "invalid empty toolsets array",
+			frontmatter: map[string]any{
+				"on": "push",
+				"tools": map[string]any{
+					"github": map[string]any{
+						"toolsets": []string{},
+					},
+				},
+			},
+			wantErr:     true,
+			errContains: "minItems",
+		},
+		{
+			name: "invalid empty issue names array",
+			frontmatter: map[string]any{
+				"on": map[string]any{
+					"issues": map[string]any{
+						"types": []string{"labeled"},
+						"names": []string{},
+					},
+				},
+			},
+			wantErr:     true,
+			errContains: "minItems",
+		},
+		{
+			name: "invalid empty pull_request names array",
+			frontmatter: map[string]any{
+				"on": map[string]any{
+					"pull_request": map[string]any{
+						"types": []string{"labeled"},
+						"names": []string{},
+					},
+				},
+			},
+			wantErr:     true,
+			errContains: "minItems",
+		},
 		{
 			name: "valid schedule with multiple cron entries",
 			frontmatter: map[string]any{
diff --git a/pkg/parser/schemas/main_workflow_schema.json b/pkg/parser/schemas/main_workflow_schema.json
index 510479189b5..fd9e83996e0 100644
--- a/pkg/parser/schemas/main_workflow_schema.json
+++ b/pkg/parser/schemas/main_workflow_schema.json
@@ -285,10 +285,7 @@
                 },
                 {
                   "not": {
-                    "anyOf": [
-                      { "required": ["branches"] },
-                      { "required": ["branches-ignore"] }
-                    ]
+                    "anyOf": [{ "required": ["branches"] }, { "required": ["branches-ignore"] }]
                   }
                 }
               ],
@@ -305,10 +302,7 @@
                     },
                     {
                       "not": {
-                        "anyOf": [
-                          { "required": ["paths"] },
-                          { "required": ["paths-ignore"] }
-                        ]
+                        "anyOf": [{ "required": ["paths"] }, { "required": ["paths-ignore"] }]
                       }
                     }
                   ]
@@ -414,7 +408,8 @@
                       "items": {
                         "type": "string",
                         "description": "Label name"
-                      }
+                      },
+                      "minItems": 1
                     }
                   ]
                 }
@@ -431,10 +426,7 @@
                 },
                 {
                   "not": {
-                    "anyOf": [
-                      { "required": ["branches"] },
-                      { "required": ["branches-ignore"] }
-                    ]
+                    "anyOf": [{ "required": ["branches"] }, { "required": ["branches-ignore"] }]
                   }
                 }
               ],
@@ -451,10 +443,7 @@
                     },
                     {
                       "not": {
-                        "anyOf": [
-                          { "required": ["paths"] },
-                          { "required": ["paths-ignore"] }
-                        ]
+                        "anyOf": [{ "required": ["paths"] }, { "required": ["paths-ignore"] }]
                       }
                     }
                   ]
@@ -486,7 +475,8 @@
                       "items": {
                         "type": "string",
                         "description": "Label name"
-                      }
+                      },
+                      "minItems": 1
                     }
                   ]
                 },
@@ -669,10 +659,7 @@
                 },
                 {
                   "not": {
-                    "anyOf": [
-                      { "required": ["branches"] },
-                      { "required": ["branches-ignore"] }
-                    ]
+                    "anyOf": [{ "required": ["branches"] }, { "required": ["branches-ignore"] }]
                   }
                 }
               ]
@@ -996,10 +983,7 @@
                 },
                 {
                   "not": {
-                    "anyOf": [
-                      { "required": ["branches"] },
-                      { "required": ["branches-ignore"] }
-                    ]
+                    "anyOf": [{ "required": ["branches"] }, { "required": ["branches-ignore"] }]
                   }
                 }
               ],
@@ -1016,10 +1000,7 @@
                     },
                     {
                       "not": {
-                        "anyOf": [
-                          { "required": ["paths"] },
-                          { "required": ["paths-ignore"] }
-                        ]
+                        "anyOf": [{ "required": ["paths"] }, { "required": ["paths-ignore"] }]
                       }
                     }
                   ]
@@ -1899,7 +1880,8 @@
               "items": {
                 "type": "string",
                 "description": "Domain name or ecosystem identifier (supports wildcards like '*.example.com' and ecosystem names like 'python', 'node')"
-              }
+              },
+              "$comment": "Empty array is valid and means deny all network access. Omit the field entirely or use network: defaults to use default network permissions."
             },
             "firewall": {
               "description": "AWF (Agent Workflow Firewall) configuration for network egress control. Only supported for Copilot engine.",
@@ -2406,7 +2388,9 @@
                       "stargazers",
                       "users"
                     ]
-                  }
+                  },
+                  "minItems": 1,
+                  "$comment": "At least one toolset is required when toolsets array is specified. Use null or omit the field to use all toolsets."
                 }
               },
               "additionalProperties": false,