Fix binary files retrieval (#1183)

* tighten content filtering logic

* add pdf retrieval test case

* add application/xml check

Author: kerobbi

pkg/github/repositories.go

@@ -601,7 +601,14 @@ func GetFileContents(getClient GetClientFn, getRawClient raw.GetRawClientFn, t t
 						}
 					}
 
-					if strings.HasPrefix(contentType, "application") || strings.HasPrefix(contentType, "text") {
+					// Determine if content is text or binary
+					isTextContent := strings.HasPrefix(contentType, "text/") ||
+						contentType == "application/json" ||
+						contentType == "application/xml" ||
+						strings.HasSuffix(contentType, "+json") ||
+						strings.HasSuffix(contentType, "+xml")
+
+					if isTextContent {
 						result := mcp.TextResourceContents{
 							URI:      resourceURI,
 							Text:     string(body),

pkg/github/repositories_test.go

@@ -157,6 +157,51 @@ func Test_GetFileContents(t *testing.T) {
 				MIMEType: "image/png",
 			},
 		},
+		{
+			name: "successful PDF file content fetch",
+			mockedClient: mock.NewMockedHTTPClient(
+				mock.WithRequestMatchHandler(
+					mock.GetReposGitRefByOwnerByRepoByRef,
+					http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+						w.WriteHeader(http.StatusOK)
+						_, _ = w.Write([]byte(`{"ref": "refs/heads/main", "object": {"sha": ""}}`))
+					}),
+				),
+				mock.WithRequestMatchHandler(
+					mock.GetReposContentsByOwnerByRepoByPath,
+					http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+						w.WriteHeader(http.StatusOK)
+						fileContent := &github.RepositoryContent{
+							Name: github.Ptr("document.pdf"),
+							Path: github.Ptr("document.pdf"),
+							SHA:  github.Ptr("pdf123"),
+							Type: github.Ptr("file"),
+						}
+						contentBytes, _ := json.Marshal(fileContent)
+						_, _ = w.Write(contentBytes)
+					}),
+				),
+				mock.WithRequestMatchHandler(
+					raw.GetRawReposContentsByOwnerByRepoByBranchByPath,
+					http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+						w.Header().Set("Content-Type", "application/pdf")
+						_, _ = w.Write(mockRawContent)
+					}),
+				),
+			),
+			requestArgs: map[string]interface{}{
+				"owner": "owner",
+				"repo":  "repo",
+				"path":  "document.pdf",
+				"ref":   "refs/heads/main",
+			},
+			expectError: false,
+			expectedResult: mcp.BlobResourceContents{
+				URI:      "repo://owner/repo/refs/heads/main/contents/document.pdf",
+				Blob:     base64.StdEncoding.EncodeToString(mockRawContent),
+				MIMEType: "application/pdf",
+			},
+		},
 		{
 			name: "successful directory content fetch",
 			mockedClient: mock.NewMockedHTTPClient(