When a file attachment upload fails in the IDE bridge (VS Code / JetBrains), the failure is now returned as a structured error object to Claude rather than silently dropped. Claude can then inform the user of the specific failure reason:
"upload failed: no OAuth token available""upload failed: could not read file (<reason>)""upload failed: server returned <status>""upload failed: unexpected server response""upload failed: network error (<reason>)""upload aborted"(when the request was cancelled)
Evidence
Bridge upload error reporting (search for "upload failed: no OAuth token available")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.