Misc. bug: [WEBUI]: Copy to clipboard fails to copy anything

[tftranslate]

Name and Version

version: 0.3.0-dev (build 10661, commit 3217633)
built with GNU 13.3.0 for Linux aarch64

Operating systems

Other? (Please let us know in description)

Which llama.cpp modules do you know to be affected?

llama-server

Command line

llama-server \
  --host 0.0.0.0 --port 8848 --threads 16 --warmup --no-mmap \
  -ngl all \
  --models-max 2 \
  --cache-prompt \
  --ui-config-file /home/tobi/llama.cpp/llama-settings.json \
  --webui-mcp-proxy \
  --models-dir /home/tobi/llama.cpp/models/empty \
  --models-preset /home/tobi/llama.cpp/models/models.ini \
  --flash-attn on \
  --mlock

Problem description & steps to reproduce

Summary

In the WebUI, there is a copy to clipboard button that is supposed to copy the latest model answer into the clipboard.
After a conversation with tool calls and/or extensive markdown formatting, this button sometimes does not work (copies an empty string into the clipboard).

Affected platforms

Browser, confirmed on Edge, Firefox, Waterfox, Librewolf and Min browser.

Steps to reproduce

Variant 1

1. Use a model of the Gemma-4 family (I tested with Gemma-4 31b in nvfp4).
2. Configure a MCP server that allows file access
3. Ask the model to "Please lst the files in my home directory and then write down the Maxwell equations in a markdown table"
4. When the model is done, click the "Copy to clipboard button", then try to paste in another window.

Variant 2

1. Import the conversation in the attached 2026-08-27_20-35-49_conv_ffea64ce_list_the_files_in_pa.jsonl file into a WebUI session in any browser.
2. Click the "Copy to clipboard button", then try to paste in another window.

Expected outcome

The clipboard should contain the Markdown of the latest model answer.

Diagnosis steps taken

• Upgraded to latest lama.server.ppp
• Selected Disable reasoning parsing in the Developer menu
• Tried to reproduce as in Variant 1 above, or using Variant 2 but with the other attached file 2026-08-27_20-39-10_conv_2afff23d_list_the_files_in_pa
• Result: Only the first reasoning block before the tool call for directory listing will be in the clipboard, but nothing else.

copy-to-clipboard-bug.zip

First Bad Commit

No response

Relevant log output

No response

[ServeurpersoCom]

I've been living with this bug for weeks and kept telling myself "later", turns out it was a data bug in the agentic message grouping, not the clipboard at all:)

[tftranslate]

I stand corrected, your PR fixes it for me. I neded to be taught by Perplexity that scrapping build/ is not enough when swithing to a PR. I also rm-rf'ed tools/ui/node_modules, tools/ui/.svelte_kit and tools/ui/dist, then rebuilt once more. Now the copy button works. Kudoz!