Long text pasted into input auto-converts to paste attachment with no content on model side

[moosepass]

Bug Report

Description:
When a long text is pasted into the input, it gets automatically converted to a paste attachment. However, the attachment arrives with no content on the model side — the model cannot read it. Real file uploads work correctly.

Steps to Reproduce:

1. Paste a large block of text into the Claude Code input
2. Observe it gets auto-converted to a paste attachment
3. The model receives the attachment but sees no content

Expected Behavior:
The pasted text should be accessible to the model, either as inline text or as a readable attachment.

Actual Behavior:
The attachment arrives empty/with no content on the model side.

Environment:

• OS: macOS Tahoe 26.5
• Claude Desktop App: 1.20186.1 (df1d8a)

Additional Context:

• Real file uploads (dragged/attached files) work fine — content is accessible
• Only paste-triggered auto-conversion is affected

[Syed2096]

Similar issue using microsoft edge and windows 11, pasted text is empty for the model.

[johnsmithau]

Also reproducing on macOS, but in the Claude Desktop chat window (claude.ai) rather than Claude Code — so this may be broader than area:tui.

Two things that may help narrow it:

1. ⇧⌘V (paste as plain text) is a reliable workaround. It bypasses the auto-conversion entirely and the content arrives intact. Ordinary ⌘V produces the empty attachment every time.

2. It appears context-length dependent rather than universal. The same clipboard content pastes fine into a new chat and fails consistently in a long-running one. That suggests a threshold rather than a flat failure, and the threshold may be conversation length rather than paste size.

Failure is silent on both sides: the paste chip renders normally in the UI, and the model reports an empty attachment. Neither party gets an error, which makes it easy to mistake for the model not reading carefully.

Same as the original report, drag-and-drop file uploads are unaffected — only paste-triggered auto-conversion.

[lennig]

Confirming this is still happening as of Aug 2026, Claude Desktop macOS. Pasting a long block of plain text (Cmd+V) auto-converts to an attachment that arrives empty on the model side — sidebar preview shows the full text, but the model reports the content as empty. Workaround that reliably works: paste without formatting (Cmd+Shift+V) instead — sends as inline text and reaches the model correctly.