fix(repos): label deferred symlink content accurately

Report contentless large symlink targets as not returned while preserving their ResourceLink and requested-path identity.

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

Copilot-Session: 21420b11-5dae-49b6-ac77-965faec7f88b

Author: SamMorrowDrums

pkg/github/repositories.go

@@ -1092,16 +1092,14 @@ func GetFileContents(t translations.TranslationHelperFunc) inventory.ServerTool
 				// GetContent when the API returns null content with a
 				// base64 encoding field, and to avoid DetectContentType
 				// misclassifying them as binary.
-				if fileSize == 0 && read.ContentAvailable {
+				if read.ContentAvailable && len(read.Content) == 0 {
 					result := &mcp.ResourceContents{
 						URI:      resourceURI,
 						Text:     "",
 						MIMEType: "text/plain",
 					}
 					message := fmt.Sprintf("successfully downloaded empty file (SHA: %s)%s", fileSHA, successNote)
-					if read.Metadata != nil {
-						message = marshalRepositoryPathMetadata(read.Metadata, "dereferenced_target", successNote)
-					}
+					message = repositoryReadMessage(read, message, successNote)
 					return attachIFC(utils.NewToolResultResource(message, result)), nil, nil
 				}
 
@@ -1117,9 +1115,9 @@ func GetFileContents(t translations.TranslationHelperFunc) inventory.ServerTool
 					message := fmt.Sprintf("File %s is too large to display (%d bytes). Use the download URL to fetch the content: %s (SHA: %s)%s",
 						path, fileSize, fileContent.GetDownloadURL(), fileSHA, successNote)
 					if read.Metadata != nil {
-						message = marshalRepositoryPathMetadata(read.Metadata, "dereferenced_target", successNote)
 						resourceLink.Title = fmt.Sprintf("Dereferenced target %s via symlink %s", read.Metadata.ResolvedTargetPath, path)
 					}
+					message = repositoryReadMessage(read, message, successNote)
 					return attachIFC(utils.NewToolResultResourceLink(
 						message,
 						resourceLink)), nil, nil
@@ -1149,9 +1147,7 @@ func GetFileContents(t translations.TranslationHelperFunc) inventory.ServerTool
 						MIMEType: contentType,
 					}
 					message := fmt.Sprintf("successfully downloaded text file (SHA: %s)%s", fileSHA, successNote)
-					if read.Metadata != nil {
-						message = marshalRepositoryPathMetadata(read.Metadata, "dereferenced_target", successNote)
-					}
+					message = repositoryReadMessage(read, message, successNote)
 					return attachIFC(utils.NewToolResultResource(message, result)), nil, nil
 				}
 
@@ -1161,9 +1157,7 @@ func GetFileContents(t translations.TranslationHelperFunc) inventory.ServerTool
 					MIMEType: contentType,
 				}
 				message := fmt.Sprintf("successfully downloaded binary file (SHA: %s)%s", fileSHA, successNote)
-				if read.Metadata != nil {
-					message = marshalRepositoryPathMetadata(read.Metadata, "dereferenced_target", successNote)
-				}
+				message = repositoryReadMessage(read, message, successNote)
 				return attachIFC(utils.NewToolResultResource(message, result)), nil, nil
 			} else if dirContent != nil {
 				// file content or file SHA is nil which means it's a directory

pkg/github/repositories_helper.go

@@ -270,6 +270,17 @@ func marshalRepositoryPathMetadata(metadata *repositoryPathMetadata, content, no
 	return string(payload)
 }
 
+func repositoryReadMessage(read *repositoryFileRead, fallback, note string) string {
+	if read.Metadata == nil {
+		return fallback
+	}
+	content := "dereferenced_target"
+	if !read.ContentAvailable {
+		content = "not_returned"
+	}
+	return marshalRepositoryPathMetadata(read.Metadata, content, note)
+}
+
 func symlinkTargetAtPath(ctx context.Context, client *github.Client, owner, repo, treeish, path string) (string, bool, *github.Response, error) {
 	entry, resp, err := getTreeEntry(ctx, client, owner, repo, treeish, path)
 	if err != nil {

pkg/github/repositories_test.go

@@ -759,7 +759,7 @@ func Test_GetFileContents_ContentlessRequestCounts(t *testing.T) {
 		assert.Equal(t, 4, requests)
 		metadata := repositoryPathMetadataFromResult(t, result)
 		assert.Equal(t, "target.bin", metadata.ResolvedTargetPath)
-		assert.Equal(t, "dereferenced_target", metadata.Content)
+		assert.Equal(t, "not_returned", metadata.Content)
 	})
 
 	t.Run("truncated tree fails closed", func(t *testing.T) {