Gmail connector can't attach local files without sending base64 through the tool call

Summary

create_draft supports attachments, but only as inline base64 in attachments[].content. Claude Code can already read my local files — it just has no way to hand one to the connector. No path, no file handle, no runtime file reference.

So attaching a 525 KB PDF and a 240 KB XLSX means pushing about 1 MB of base64 through the tool call to move 765 KB of files. Fine for something tiny, but it becomes impractical quickly — and the files I want to attach are usually ones Claude Code just generated.

Repro

1. Claude Code desktop, Code tab, Gmail connector enabled.
2. Put report.pdf and data.xlsx in the workspace.
3. Ask Claude to draft an email and attach both files.
4. create_draft wants each attachment as inline base64. There's no way to just point it at the local file.

Expected

Something like either:

attachments: [{ file_ref: "..." }]

or:

attachments: [{ path: "/workspace/report.pdf" }]

Claude Code reads the file locally and handles the upload/encoding itself, instead of putting the whole file in the tool-call payload.

Actual

Inline base64 is the only option.

The Chrome extension's file_upload works around it, but only if you have the extension. The connector itself still can't take a file that Claude Code already has.

Related

• anthropics/claude-ai-mcp#819 — Gmail exposes attachment IDs, but there's no tool to download the attachment content.
• #83571 — create_draft accepts base64 attachments even though the tool description says attachments aren't supported.
• #28575 — earlier request for Gmail draft attachment support.
• #76717 — earlier report about missing attachment downloads; closed as unrelated to Claude Code.

Environment

• Claude Code desktop app, Code tab
• Windows 11
• First-party Gmail connector