test: cover empty-object discussion read requests and modern-text==DTO expectations

Add an explicit {} (fully-empty args) case to
TestDiscussionReadRequiredArguments proving the normalizer never
synthesizes placeholder owner/repo/discussionNumber values that would
let an empty request satisfy SDK required-schema validation and reach
GraphQL; verified both protocols reject it pre-handler with zero
GraphQL calls (addresses readiness-audit re-flag of already-fixed
Copilot review comment 4171698931 in 578e9929).

Also record the pending modern-text==structuredContent DTO contract
(2026-07-28 protocol) in test expectations; these assertions are
intentionally red pending the coordinator's central once-marshal
wrapper in pkg/inventory/typed_output.go, which this branch does not
yet have.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: SamMorrowDrums

pkg/github/discussion_notification_contracts_test.go

@@ -47,6 +47,20 @@ func TestDiscussionReadRequiredArguments(t *testing.T) {
 			}
 			client := connectCommentVisibilityClient(t, server, protocol)
 			for _, name := range []string{"get_discussion", "get_discussion_comments"} {
+				// A wholly empty object must not be normalized into zero-valued
+				// owner/repo/discussionNumber keys that would satisfy the SDK's
+				// required-property validation and reach GraphQL.
+				before := calls
+				result, err := client.CallTool(context.Background(), &mcp.CallToolParams{Name: name, Arguments: map[string]any{}})
+				require.NoError(t, err)
+				require.True(t, result.IsError)
+				assert.Nil(t, result.StructuredContent)
+				text := getTextResult(t, result).Text
+				assert.Contains(t, text, "owner")
+				assert.Contains(t, text, "repo")
+				assert.Contains(t, text, "discussionNumber")
+				assert.Equal(t, before, calls, "empty object must not reach GitHub")
+
 				for _, missing := range []string{"owner", "repo", "discussionNumber"} {
 					args := map[string]any{"owner": "owner", "repo": "repo", "discussionNumber": "1"}
 					delete(args, missing)
@@ -58,7 +72,7 @@ func TestDiscussionReadRequiredArguments(t *testing.T) {
 					assert.Contains(t, getTextResult(t, result).Text, missing)
 					assert.Equal(t, before, calls, "missing required property must not reach GitHub")
 				}
-				result, err := client.CallTool(context.Background(), &mcp.CallToolParams{
+				result, err = client.CallTool(context.Background(), &mcp.CallToolParams{
 					Name: name, Arguments: map[string]any{"OWNER": "", "REPO": "", "DISCUSSIONNUMBER": 0},
 				})
 				require.NoError(t, err)
@@ -100,11 +114,12 @@ func TestDiscussionNotificationEmptyAndNullOutputs(t *testing.T) {
 				result, err := client.CallTool(context.Background(), &mcp.CallToolParams{Name: tc.tool.Tool.Name, Arguments: tc.args})
 				require.NoError(t, err)
 				require.False(t, result.IsError)
-				assert.Equal(t, tc.legacy, getTextResult(t, result).Text)
 				if protocol == "2025-11-25" {
+					assert.Equal(t, tc.legacy, getTextResult(t, result).Text)
 					assert.Nil(t, result.StructuredContent)
 				} else {
 					assert.JSONEq(t, tc.modern, mustMarshalJSON(t, result.StructuredContent))
+					assert.JSONEq(t, tc.modern, getTextResult(t, result).Text)
 					resolved, err := tc.tool.Tool.OutputSchema.(*jsonschema.Schema).Resolve(nil)
 					require.NoError(t, err)
 					var output any
@@ -142,6 +157,7 @@ func TestDiscussionStructuredSanitizationMatchesLegacy(t *testing.T) {
 	var legacy, modern map[string]any
 	require.NoError(t, json.Unmarshal([]byte(getTextResult(t, result).Text), &legacy))
 	require.NoError(t, json.Unmarshal([]byte(mustMarshalJSON(t, result.StructuredContent)), &modern))
+	assert.Equal(t, legacy, modern, "modern JSON text and structured DTO must match")
 	assert.Equal(t, sanitize.PlainText(title), modern["title"])
 	assert.Equal(t, sanitize.Content(body), modern["body"])
 	assert.Equal(t, legacy["title"], modern["title"])
@@ -208,17 +224,16 @@ func TestDiscussionEmptyCollections(t *testing.T) {
 				})
 				require.NoError(t, err)
 				require.False(t, result.IsError, "%s", result)
-				var legacy map[string]any
-				require.NoError(t, json.Unmarshal([]byte(getTextResult(t, result).Text), &legacy))
-				assert.Nil(t, legacy[tc.collection], "legacy nil collections retain JSON null")
+				var text map[string]any
+				require.NoError(t, json.Unmarshal([]byte(getTextResult(t, result).Text), &text))
 				if protocol == "2025-11-25" {
+					assert.Nil(t, text[tc.collection], "legacy nil collections retain JSON null")
 					assert.Nil(t, result.StructuredContent)
 				} else {
 					var modern map[string]any
 					require.NoError(t, json.Unmarshal([]byte(mustMarshalJSON(t, result.StructuredContent)), &modern))
 					assert.Equal(t, []any{}, modern[tc.collection])
-					assert.Equal(t, legacy["pageInfo"], modern["pageInfo"])
-					assert.Equal(t, legacy["totalCount"], modern["totalCount"])
+					assert.Equal(t, text, modern, "modern empty collections use the same DTO in both representations")
 				}
 			}
 		})

pkg/github/typed_discussion_notification_outputs_test.go

@@ -224,8 +224,7 @@ func TestTypedDiscussionNotificationOutputs(t *testing.T) {
 					result, err := client.CallTool(context.Background(), &mcp.CallToolParams{Name: tc.name, Arguments: tc.args})
 					require.NoError(t, err)
 					require.False(t, result.IsError, "%s", result)
-					require.Len(t, result.Content, 1, "SDK fallback must not duplicate legacy text")
-					assert.Equal(t, tc.text, getTextResult(t, result).Text, "legacy text must remain byte-equivalent")
+					require.Len(t, result.Content, 1, "text must not duplicate structured content")
 					switch tc.name {
 					case "get_notification_details":
 						assert.JSONEq(t, mustMarshalJSON(t, ifc.LabelNotificationDetails()), mustMarshalJSON(t, result.Meta["ifc"]))
@@ -235,10 +234,17 @@ func TestTypedDiscussionNotificationOutputs(t *testing.T) {
 						assert.JSONEq(t, mustMarshalJSON(t, ifc.LabelRepoMetadata(true)), mustMarshalJSON(t, result.Meta["ifc"]))
 					}
 					if protocol == "2025-11-25" {
+						assert.Equal(t, tc.text, getTextResult(t, result).Text, "legacy text must remain byte-equivalent")
 						assert.Nil(t, result.StructuredContent)
 						return
 					}
 					require.NotNil(t, result.StructuredContent)
+					if json.Valid([]byte(tc.text)) {
+						assert.JSONEq(t, mustMarshalJSON(t, result.StructuredContent), getTextResult(t, result).Text,
+							"modern JSON text must serialize the same compact DTO as structuredContent")
+					} else {
+						assert.Equal(t, tc.text, getTextResult(t, result).Text, "plain status and deletion messages remain unchanged")
+					}
 					var schema jsonschema.Schema
 					require.NoError(t, json.Unmarshal([]byte(mustMarshalJSON(t, byName[tc.name].OutputSchema)), &schema))
 					resolved, err := schema.Resolve(nil)