This commit implements a new feature that allows Gmail attachments to be
served via HTTP URLs instead of returning base64-encoded data in the tool
response. This avoids consuming LLM context window space and token budgets
for large attachments.
Architecture:
-------------
The implementation works in both stdio and streamable-http transport modes:
1. Temp File Storage (core/attachment_storage.py):
- New AttachmentStorage class manages temporary file storage in ./tmp/attachments/
- Uses UUID-based file IDs to prevent guessing/unauthorized access
- Tracks metadata: filename, mime type, size, creation/expiration times
- Files expire after 1 hour (configurable) with automatic cleanup support
- Handles base64 decoding and file writing
2. HTTP Route Handlers:
- Added /attachments/{file_id} route to main FastMCP server (streamable-http mode)
- Added same route to MinimalOAuthServer (stdio mode)
- Both routes serve files with proper Content-Type headers via FileResponse
- Returns 404 for expired or missing attachments
3. Modified get_gmail_attachment_content():
- Now saves attachments to temp storage and returns HTTP URL
- Attempts to fetch filename/mimeType from message metadata (best effort)
- Handles stateless mode gracefully (skips file saving, shows preview)
- Falls back to base64 preview if file saving fails
- URL generation respects WORKSPACE_EXTERNAL_URL for reverse proxy setups
Key Features:
-------------
- Works in both stdio and streamable-http modes (uses existing HTTP servers)
- Respects stateless mode (no file writes when WORKSPACE_MCP_STATELESS_MODE=true)
- Secure: UUID-based file IDs prevent unauthorized access
- Automatic expiration: Files cleaned up after 1 hour
- Reverse proxy support: Uses WORKSPACE_EXTERNAL_URL if configured
- Graceful degradation: Falls back to preview if storage fails
Benefits:
---------
- Avoids context window bloat: Large attachments don't consume LLM tokens
- Better performance: Clients can stream/download files directly
- More efficient: No need to decode base64 in client applications
- Works across network boundaries: URLs accessible from any client
The feature maintains backward compatibility - if file saving fails or stateless
mode is enabled, the function falls back to showing a base64 preview.
Added ability to upload local files to Google Drive using file:// URL scheme
in the create_drive_file tool. This enables uploading files from /tmp and
other local paths without requiring HTTP/HTTPS hosting.
Changes:
- Added urllib.parse.urlparse and pathlib.Path imports
- Detect file:// URLs and read directly from local filesystem
- Validate file exists before attempting upload
- Updated docstring to reflect support for file://, http://, and https://
- Added error handling for unsupported URL schemes
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Co-Authored-By: Claude <noreply@anthropic.com>
- Added comprehensive update_drive_file function to modify Google Drive file metadata
- Fixed OAuth scope issue by using 'drive_file' instead of non-existent 'drive_write'
- Supports moving files, renaming, updating descriptions, managing sharing permissions
- Includes support for custom properties and file status (starred/trashed)
- Updated README.md and tool_tiers.yaml documentation
- Successfully tested with all parameters
Fixes#220 (OAuth stdio mode authentication issues)
Previously, the metadataHeaders parameter only requested Subject and
From fields from the Gmail API, even though To and Cc are standard
metadata fields. This updates all metadata API calls to include To
and Cc in both single message and batch operations.
Changes:
- Updated metadataHeaders to include To, Cc in all API calls
- Extended _extract_headers() calls to request To, Cc
- Updated response formatting to display To, Cc fields
- Handles missing To/Cc gracefully with empty strings
- Updated docstrings to reflect new fields in responses
Affected functions:
- get_gmail_message_content() (gmail/gmail_tools.py:369-457)
- get_gmail_messages_content_batch() (gmail/gmail_tools.py:463-638)
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Co-Authored-By: Claude <noreply@anthropic.com>
## Problem
Emails sent via send_gmail_message were always showing as from a default
user account regardless of which account was specified in the
user_google_email parameter.
## Root Cause
The _prepare_gmail_message() function was not setting the From header in
the MIME message. Gmail API defaults to the primary send-as address when
no From header is provided.
## Solution
- Added from_email parameter to _prepare_gmail_message()
- Set From header explicitly: message["From"] = from_email
- Updated send_gmail_message() to pass user_google_email as from_email
- Updated draft_gmail_message() to pass user_google_email as from_email
- Capitalized MIME headers (Subject, From, To, Cc, Bcc) per conventions
## Testing
Verified emails now correctly show sender address for multiple accounts.
Each account now properly displays its own address in the From field.
Fixes multi-account email sending functionality.
