[Bug] Chat settings could not be persisted

[ursadorable]

Whenever I try to save a new preset, I get the error: "Chat settings could not be persisted" after upgrading to the latest version the other day.

My understanding is that Unsloth went from saving chat history and settings from browser storage to a local DB. Ever since this happened, I can no longer create new presets.

I've purged the '.unsloth' folder on my Fedora 43 install, cleared out the browser storage and re-installed Unsloth.

The issue persists.

[Imagineer99]

hey thanks for sharing, does this issue occur with you when local models are loaded, or with only connected models?

[ursadorable]

Thank you for the question. I only use local models, however it will produce the same error whether or not a model is loaded.

[Imagineer99]

Thank you for the question. I only use local models, however it will produce the same error whether or not a model is loaded.

I was not able to repro the exact on my local. since this also happens with local/no model loaded, to narrow it down. could you try saving a preset with DevTools ->Network open and share the failing PUT /api/chat/settings status code, response body, and request payload? Backend terminal logs from the same moment would also help.

[ursadorable]

As requested. I hope this helps. Cheers!

Put Request:

scheme
	http
host
	localhost:8888
filename
	/api/chat/settings
Address
	127.0.0.1:8888
Status
400
Bad Request
VersionHTTP/1.1
Transferred1.02 kB (197 B size)
Referrer Policyno-referrer
DNS ResolutionSystem

Response Headers:

HTTP/1.1 400 Bad Request
date: Fri, 29 May 2026 23:44:55 GMT
content-length: 197
content-type: application/json
content-security-policy: default-src 'self'; img-src 'self' data: blob: https://t0.gstatic.com https://t1.gstatic.com https://t2.gstatic.com https://t3.gstatic.com https://www.google.com; connect-src 'self' https://huggingface.co https://datasets-server.huggingface.co; style-src 'self' 'unsafe-inline'; script-src 'self'; font-src 'self' data:; frame-ancestors 'none'; form-action 'self'; base-uri 'self'
x-frame-options: DENY
x-content-type-options: nosniff
referrer-policy: no-referrer
permissions-policy: camera=(), microphone=(), geolocation=(), interest-cohort=()
server: unsloth-studio
access-control-allow-origin: http://localhost:8888
access-control-allow-credentials: true
vary: Origin

Request Headers:

PUT /api/chat/settings HTTP/1.1
Host: localhost:8888
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:151.0) Gecko/20100101 Firefox/151.0
Accept: */*
Accept-Language: en-CA,en-US;q=0.9,en;q=0.8
Accept-Encoding: gzip, deflate, br, zstd
authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ1bnNsb3RoIiwiZXhwIjoxNzgwMDk4NzgxfQ.vJZBkHkP7OXmlVnG5RigZFm7RPF5HFI9hFPPIMO9Wxg
content-type: application/json
Content-Length: 318
Origin: http://localhost:8888
Connection: keep-alive
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Priority: u=4

Terminal:

{"timestamp": "2026-05-29T23:44:56.338370Z", "level": "info", "event": "request_completed", "method": "PUT", "path": "/api/chat/settings", "status_code": 400, "process_time_ms": 1.11}
{"timestamp": "2026-05-29T23:45:28.629244Z", "level": "info", "event": "request_completed", "method": "POST", "path": "/api/chat/settings", "status_code": 405, "process_time_ms": 0.31}

[ursadorable]

Sorry, there was one other error I saw:

Content-Security-Policy: The page’s settings blocked an inline script (script-src-elem) from being executed because it violates the following directive: “script-src 'self'”. Consider using a hash ('sha256-5yZ7eUvr7d8X4ldkD+TyXkqkNRzk12G3tfQpJOM9hL4=') or a nonce. sandbox eval code:1060:80
XHRPUT
http://localhost:8888/api/chat/settings
[HTTP/1.1 400 Bad Request 2ms]

[rolandtannous]

what are your operating system , and browser settings? and do you have any ad-blockers that are active?

[ursadorable]

Fedora 43, Firefox and Chromium and no adblocker. I downloaded Chromium as a secondary browser just to rule out Firefox.

[vtgolf]

Hi!
For me also is the same.. Vivaldi and Chrome. Model is "unsloth/gemma-4-E4B-it-GGUF"
In the log it says:
{"timestamp": "2026-06-05T11:03:06.910996Z", "level": "info", "event": "request_completed", "method": "PUT", "path": "/api/chat/settings", "status_code": 400, "process_time_ms": 4.1}

Payload sent:

{
  "customPresets": [
    {
      "name": "General",
      "params": {
        "temperature": 0.6,
        "topP": 0.95,
        "topK": 20,
        "minP": 0.01,
        "repetitionPenalty": 1,
        "presencePenalty": 0,
        "maxSeqLength": 4096,
        "maxTokens": 8192,
        "systemPrompt": "The System Prompt\n\n## Blah blah blah.",
        "trustRemoteCode": false,
        "fastMode": false
      }
    }
  ],
  "activePreset": "General",
  "activePresetSource": "custom"
}

Answer:

{
  "detail": [
    {
      "type": "extra_forbidden",
      "loc": [
        "customPresets",
        0,
        "params",
        "fastMode"
      ],
      "msg": "Extra inputs are not permitted",
      "input": false,
      "url": "https://errors.pydantic.dev/2.13/v/extra_forbidden"
    }
  ]
}

[vtgolf]

If I apply fix on #5870 works fine and saves

[danielhanchen]

Merged #5870 so hopefully this is fixed!

[danielhanchen]

Fixed by #5870, now merged to main, and confirmed working by @vtgolf.

The backend chat settings schema rejected the frontend's fastMode key because ChatInferenceSettings used extra = "forbid" without declaring it, so PUT /api/chat/settings returned a 400 and presets would not save. The field is now allowed (in both top-level inference params and custom preset params), plus there is a regression test and a guard test that keeps the schema in sync with the frontend going forward.

Closing as this is resolved on main and will be in the next release. If you still hit it after updating, please reopen with the failing payload and status code.