From 443c0bea8e4886c5cfb048f28a919d3c557aedfc Mon Sep 17 00:00:00 2001
From: Classic298 <27028174+Classic298@users.noreply.github.com>
Date: Tue, 28 Jul 2026 23:31:44 +0200
Subject: [PATCH] fix: use the active chat model for context compaction when no
 compaction model is set

The "Context Compaction Model" setting offers a "Current Model" option, described in the admin panel as following the active chat model. That option writes an empty string, which `_generate_summary` treated as "no override" and then resolved through `get_task_model_id`, returning the configured Local or External Task Model whenever one is set. On any instance with a task model configured, compaction therefore ran on the task model and "Current Model" did nothing.

Resolve the compaction model directly instead: use the configured compaction model when it is available, otherwise the active chat model. Task model settings keep governing title, tags, query and follow-up generation; only compaction stops inheriting them. Admins who want compaction on the task model can select that model explicitly in the compaction dropdown.

Note for existing deployments: instances that set a task model and left the compaction model unset will now compact on the active chat model, which is what the setting always claimed to do but may be a more expensive model. Select the intended model in the Context Compaction Model dropdown to pin it.

Fixes #27603
---
 .../open_webui/utils/context_compaction.py    | 27 +++++--------------
 1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/backend/open_webui/utils/context_compaction.py b/backend/open_webui/utils/context_compaction.py
index ff84481a5e..3afd5597be 100644
--- a/backend/open_webui/utils/context_compaction.py
+++ b/backend/open_webui/utils/context_compaction.py
@@ -11,7 +11,6 @@ from open_webui.utils.json_codec import JSONCodec
 from open_webui.utils.misc import get_content_from_message, get_last_user_message, get_message_list
 from open_webui.utils.payload import apply_params_to_form_data
 from open_webui.utils.task import (
-    get_task_model_id,
     prompt_template,
     prompt_variables_template,
     replace_messages_variable,
@@ -366,25 +365,13 @@ async def _generate_summary(
     from open_webui.utils.chat import generate_chat_completion
 
     task_config = await Config.get_many(
-        'task.model.default',
-        'task.model.external',
         'task.model.params',
         'chat.context_compaction.model',
     )
-    context_compaction_model = task_config.get('chat.context_compaction.model')
-    task_model_id = (
-        context_compaction_model
-        if context_compaction_model in models
-        else get_task_model_id(
-            model_id,
-            task_config.get('task.model.default'),
-            task_config.get('task.model.external'),
-            models,
-        )
-    )
-    if task_model_id not in models:
-        task_model_id = model_id
-    if task_model_id not in models:
+    configured_model_id = task_config.get('chat.context_compaction.model')
+    # Unset or unavailable falls back to the active chat model, never the generic task model.
+    compaction_model_id = configured_model_id if configured_model_id in models else model_id
+    if compaction_model_id not in models:
         raise ValueError('No available model for context compaction')
 
     summary_prompt_template = summary_prompt_template.strip() or DEFAULT_CONTEXT_COMPACTION_PROMPT
@@ -401,11 +388,11 @@ async def _generate_summary(
         task_model_params = {}
     task_model_params = {key: value for key, value in task_model_params.items() if value is not None and value != ''}
     task_model_params = task_model_params or {
-        'max_tokens': models[task_model_id].get('info', {}).get('params', {}).get('max_tokens', 1000)
+        'max_tokens': models[compaction_model_id].get('info', {}).get('params', {}).get('max_tokens', 1000)
     }
 
     payload = {
-        'model': task_model_id,
+        'model': compaction_model_id,
         'messages': [{'role': 'user', 'content': prompt}],
         'stream': False,
         'metadata': {
@@ -414,7 +401,7 @@ async def _generate_summary(
         },
     }
 
-    payload = apply_params_to_form_data(payload, models[task_model_id], task_model_params)
+    payload = apply_params_to_form_data(payload, models[compaction_model_id], task_model_params)
     response = await generate_chat_completion(request, form_data=payload, user=user)
     summary = _response_text(response).strip()
     if summary: