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The getAttachment and exportAttachment MCP handlers had att.Size (database metadata) available but never checked it against
maxAttachmentSize before calling readAttachmentFile. This meant:
- Unnecessary file I/O (open + stat) for attachments already known to be too large
- Misleading error messages ("file not available" instead of "too large")
- If the file existed, the full stat + LimitReader pipeline would execute before rejecting
The Fix (2 lines of logic, added to 2 call sites)
Added a pre-flight att.Size > maxAttachmentSize check in both getAttachment (line 153) and exportAttachment (line 219), immediately
after confirming the attachments directory is configured and before any file I/O.
Changes Made
- internal/mcp/handlers.go: Added pre-flight size check in both handlers (2x 3 lines)
- internal/mcp/server_test.go: Added TestGetAttachment_RejectsOversizedBeforeFileIO and
TestExportAttachment_RejectsOversizedBeforeFileIO (44 lines)
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The getAttachment and exportAttachment MCP handlers had att.Size (database metadata) available but never checked it against maxAttachmentSize before calling readAttachmentFile. This meant:
The Fix (2 lines of logic, added to 2 call sites)
Added a pre-flight att.Size > maxAttachmentSize check in both getAttachment (line 153) and exportAttachment (line 219), immediately after confirming the attachments directory is configured and before any file I/O.
Changes Made