feat: add agent loop protection - max iterations and tool result truncation

- Add max-tool-iterations config (default 16) to prevent runaway agent loops
- Add max-tool-result-chars config (default 8000) to truncate oversized tool results
- Both settings are configurable in pipeline UI under Local Agent settings
- Logs warnings when limits are hit for debugging

Closes #2051

src/langbot/pkg/core/app.py

@@ -9,6 +9,7 @@ from ..platform import botmgr as im_mgr
 from ..platform.webhook_pusher import WebhookPusher
 from ..provider.session import sessionmgr as llm_session_mgr
 from ..provider.modelmgr import modelmgr as llm_model_mgr
+
 from langbot.pkg.provider.tools import toolmgr as llm_tool_mgr
 from ..config import manager as config_mgr
 from ..command import cmdmgr
@@ -30,6 +31,7 @@ from ..api.http.service import mcp as mcp_service
 from ..api.http.service import apikey as apikey_service
 from ..api.http.service import webhook as webhook_service
 from ..api.http.service import monitoring as monitoring_service
+
 from ..discover import engine as discover_engine
 from ..storage import mgr as storagemgr
 from ..utils import logcache

src/langbot/pkg/persistence/migrations/dbm023_model_fallback_config.py

@@ -0,0 +1,102 @@
+from .. import migration
+
+import sqlalchemy
+import json
+
+
+@migration.migration_class(23)
+class DBMigrateModelFallbackConfig(migration.DBMigration):
+    """Convert model field from plain UUID string to object with primary/fallbacks"""
+
+    async def upgrade(self):
+        """Upgrade"""
+        result = await self.ap.persistence_mgr.execute_async(
+            sqlalchemy.text('SELECT uuid, config FROM legacy_pipelines')
+        )
+        pipelines = result.fetchall()
+
+        current_version = self.ap.ver_mgr.get_current_version()
+
+        for pipeline_row in pipelines:
+            uuid = pipeline_row[0]
+            config = json.loads(pipeline_row[1]) if isinstance(pipeline_row[1], str) else pipeline_row[1]
+
+            if 'ai' not in config or 'local-agent' not in config['ai']:
+                continue
+
+            local_agent = config['ai']['local-agent']
+            changed = False
+
+            # Convert model from string to object
+            model_value = local_agent.get('model', '')
+            if isinstance(model_value, str):
+                local_agent['model'] = {
+                    'primary': model_value,
+                    'fallbacks': [],
+                }
+                changed = True
+
+            # Remove leftover fallback-models field if present
+            if 'fallback-models' in local_agent:
+                del local_agent['fallback-models']
+                changed = True
+
+            if not changed:
+                continue
+
+            # Update using raw SQL with compatibility for both SQLite and PostgreSQL
+            if self.ap.persistence_mgr.db.name == 'postgresql':
+                await self.ap.persistence_mgr.execute_async(
+                    sqlalchemy.text(
+                        'UPDATE legacy_pipelines SET config = :config::jsonb, for_version = :for_version WHERE uuid = :uuid'
+                    ),
+                    {'config': json.dumps(config), 'for_version': current_version, 'uuid': uuid},
+                )
+            else:
+                await self.ap.persistence_mgr.execute_async(
+                    sqlalchemy.text(
+                        'UPDATE legacy_pipelines SET config = :config, for_version = :for_version WHERE uuid = :uuid'
+                    ),
+                    {'config': json.dumps(config), 'for_version': current_version, 'uuid': uuid},
+                )
+
+    async def downgrade(self):
+        """Downgrade"""
+        result = await self.ap.persistence_mgr.execute_async(
+            sqlalchemy.text('SELECT uuid, config FROM legacy_pipelines')
+        )
+        pipelines = result.fetchall()
+
+        current_version = self.ap.ver_mgr.get_current_version()
+
+        for pipeline_row in pipelines:
+            uuid = pipeline_row[0]
+            config = json.loads(pipeline_row[1]) if isinstance(pipeline_row[1], str) else pipeline_row[1]
+
+            if 'ai' not in config or 'local-agent' not in config['ai']:
+                continue
+
+            local_agent = config['ai']['local-agent']
+
+            # Convert model from object back to string
+            model_value = local_agent.get('model', '')
+            if isinstance(model_value, dict):
+                local_agent['model'] = model_value.get('primary', '')
+            else:
+                continue
+
+            # Update using raw SQL with compatibility for both SQLite and PostgreSQL
+            if self.ap.persistence_mgr.db.name == 'postgresql':
+                await self.ap.persistence_mgr.execute_async(
+                    sqlalchemy.text(
+                        'UPDATE legacy_pipelines SET config = :config::jsonb, for_version = :for_version WHERE uuid = :uuid'
+                    ),
+                    {'config': json.dumps(config), 'for_version': current_version, 'uuid': uuid},
+                )
+            else:
+                await self.ap.persistence_mgr.execute_async(
+                    sqlalchemy.text(
+                        'UPDATE legacy_pipelines SET config = :config, for_version = :for_version WHERE uuid = :uuid'
+                    ),
+                    {'config': json.dumps(config), 'for_version': current_version, 'uuid': uuid},
+                )

src/langbot/pkg/pipeline/preproc/preproc.py

@@ -36,17 +36,36 @@ class PreProcessor(stage.PipelineStage):
         session = await self.ap.sess_mgr.get_session(query)
 
         # When not local-agent, llm_model is None
-        try:
+        llm_model = None
-            llm_model = (
+        if selected_runner == 'local-agent':
-                await self.ap.model_mgr.get_model_by_uuid(query.pipeline_config['ai']['local-agent']['model'])
+            # Read model config — new format is { primary: str, fallbacks: [str] },
-                if selected_runner == 'local-agent'
+            # but handle legacy plain string for backward compatibility
-                else None
+            model_config = query.pipeline_config['ai']['local-agent'].get('model', {})
-            )
+            if isinstance(model_config, str):
-        except ValueError:
+                # Legacy format: plain UUID string
-            self.ap.logger.warning(
+                primary_uuid = model_config
-                f'LLM model {query.pipeline_config["ai"]["local-agent"]["model"] + " "}not found or not configured'
+                fallback_uuids = []
-            )
+            else:
-            llm_model = None
+                primary_uuid = model_config.get('primary', '')
+                fallback_uuids = model_config.get('fallbacks', [])
+
+            if primary_uuid:
+                try:
+                    llm_model = await self.ap.model_mgr.get_model_by_uuid(primary_uuid)
+                except ValueError:
+                    self.ap.logger.warning(f'LLM model {primary_uuid} not found or not configured')
+
+            # Resolve fallback model UUIDs
+            if fallback_uuids:
+                valid_fallbacks = []
+                for fb_uuid in fallback_uuids:
+                    try:
+                        await self.ap.model_mgr.get_model_by_uuid(fb_uuid)
+                        valid_fallbacks.append(fb_uuid)
+                    except ValueError:
+                        self.ap.logger.warning(f'Fallback model {fb_uuid} not found, skipping')
+                if valid_fallbacks:
+                    query.variables['_fallback_model_uuids'] = valid_fallbacks
 
         conversation = await self.ap.sess_mgr.get_conversation(
             query,
@@ -61,20 +80,28 @@ class PreProcessor(stage.PipelineStage):
         query.prompt = conversation.prompt.copy()
         query.messages = conversation.messages.copy()
 
-        if selected_runner == 'local-agent' and llm_model:
+        if selected_runner == 'local-agent':
             query.use_funcs = []
-            query.use_llm_model_uuid = llm_model.model_entity.uuid
+            if llm_model:
+                query.use_llm_model_uuid = llm_model.model_entity.uuid
 
-            if llm_model.model_entity.abilities.__contains__('func_call'):
+                if llm_model.model_entity.abilities.__contains__('func_call'):
-                # Get bound plugins and MCP servers for filtering tools
+                    # Get bound plugins and MCP servers for filtering tools
+                    bound_plugins = query.variables.get('_pipeline_bound_plugins', None)
+                    bound_mcp_servers = query.variables.get('_pipeline_bound_mcp_servers', None)
+                    query.use_funcs = await self.ap.tool_mgr.get_all_tools(bound_plugins, bound_mcp_servers)
+
+                    self.ap.logger.debug(f'Bound plugins: {bound_plugins}')
+                    self.ap.logger.debug(f'Bound MCP servers: {bound_mcp_servers}')
+                    self.ap.logger.debug(f'Use funcs: {query.use_funcs}')
+
+            # If primary model doesn't support func_call but fallback models exist,
+            # load tools anyway since fallback models may support them
+            if not query.use_funcs and query.variables.get('_fallback_model_uuids'):
                 bound_plugins = query.variables.get('_pipeline_bound_plugins', None)
                 bound_mcp_servers = query.variables.get('_pipeline_bound_mcp_servers', None)
                 query.use_funcs = await self.ap.tool_mgr.get_all_tools(bound_plugins, bound_mcp_servers)
 
-                self.ap.logger.debug(f'Bound plugins: {bound_plugins}')
-                self.ap.logger.debug(f'Bound MCP servers: {bound_mcp_servers}')
-                self.ap.logger.debug(f'Use funcs: {query.use_funcs}')
-
         sender_name = ''
 
         if isinstance(query.message_event, platform_events.GroupMessage):

src/langbot/pkg/provider/runners/localagent.py

@@ -4,6 +4,7 @@ import json
 import copy
 import typing
 from .. import runner
+from ..modelmgr import requester as modelmgr_requester
 import langbot_plugin.api.entities.builtin.pipeline.query as pipeline_query
 import langbot_plugin.api.entities.builtin.provider.message as provider_message
 import langbot_plugin.api.entities.builtin.rag.context as rag_context
@@ -26,21 +27,117 @@ Respond in the same language as the user's input.
 
 @runner.runner_class('local-agent')
 class LocalAgentRunner(runner.RequestRunner):
-    """本地Agent请求运行器"""
+    """Local agent request runner"""
 
-    class ToolCallTracker:
+    async def _get_model_candidates(
-        """工具调用追踪器"""
+        self,
+        query: pipeline_query.Query,
+    ) -> list[modelmgr_requester.RuntimeLLMModel]:
+        """Build ordered list of models to try: primary model + fallback models."""
+        candidates = []
 
-        def __init__(self):
+        # Primary model
-            self.active_calls: dict[str, dict] = {}
+        if query.use_llm_model_uuid:
-            self.completed_calls: list[provider_message.ToolCall] = []
+            try:
+                primary = await self.ap.model_mgr.get_model_by_uuid(query.use_llm_model_uuid)
+                candidates.append(primary)
+            except ValueError:
+                self.ap.logger.warning(f'Primary model {query.use_llm_model_uuid} not found')
+
+        # Fallback models
+        fallback_uuids = (query.variables or {}).get('_fallback_model_uuids', [])
+        for fb_uuid in fallback_uuids:
+            try:
+                fb_model = await self.ap.model_mgr.get_model_by_uuid(fb_uuid)
+                candidates.append(fb_model)
+            except ValueError:
+                self.ap.logger.warning(f'Fallback model {fb_uuid} not found, skipping')
+
+        return candidates
+
+    async def _invoke_with_fallback(
+        self,
+        query: pipeline_query.Query,
+        candidates: list[modelmgr_requester.RuntimeLLMModel],
+        messages: list,
+        funcs: list,
+        remove_think: bool,
+    ) -> tuple[provider_message.Message, modelmgr_requester.RuntimeLLMModel]:
+        """Try non-streaming invocation with sequential fallback. Returns (message, model_used)."""
+        last_error = None
+        for model in candidates:
+            try:
+                msg = await model.provider.invoke_llm(
+                    query,
+                    model,
+                    messages,
+                    funcs if model.model_entity.abilities.__contains__('func_call') else [],
+                    extra_args=model.model_entity.extra_args,
+                    remove_think=remove_think,
+                )
+                return msg, model
+            except Exception as e:
+                last_error = e
+                self.ap.logger.warning(f'Model {model.model_entity.name} failed: {e}, trying next fallback...')
+        raise last_error or RuntimeError('No model candidates available')
+
+    async def _invoke_stream_with_fallback(
+        self,
+        query: pipeline_query.Query,
+        candidates: list[modelmgr_requester.RuntimeLLMModel],
+        messages: list,
+        funcs: list,
+        remove_think: bool,
+    ) -> tuple[typing.AsyncGenerator, modelmgr_requester.RuntimeLLMModel]:
+        """Try streaming invocation with sequential fallback. Returns (stream_generator, model_used).
+
+        Fallback is only possible before any chunks have been yielded to the client.
+        Once streaming starts, the model is committed.
+        """
+        last_error = None
+        for model in candidates:
+            try:
+                stream = model.provider.invoke_llm_stream(
+                    query,
+                    model,
+                    messages,
+                    funcs if model.model_entity.abilities.__contains__('func_call') else [],
+                    extra_args=model.model_entity.extra_args,
+                    remove_think=remove_think,
+                )
+                # Attempt to get the first chunk to verify the stream works
+                first_chunk = await stream.__anext__()
+
+                async def _chain_stream(first, rest):
+                    yield first
+                    async for chunk in rest:
+                        yield chunk
+
+                return _chain_stream(first_chunk, stream), model
+            except StopAsyncIteration:
+                # Empty stream — treat as success (model returned nothing)
+                async def _empty_stream():
+                    return
+                    yield  # make it a generator
+
+                return _empty_stream(), model
+            except Exception as e:
+                last_error = e
+                self.ap.logger.warning(f'Model {model.model_entity.name} stream failed: {e}, trying next fallback...')
+        raise last_error or RuntimeError('No model candidates available')
 
     async def run(
         self, query: pipeline_query.Query
     ) -> typing.AsyncGenerator[provider_message.Message | provider_message.MessageChunk, None]:
-        """运行请求"""
+        """Run request"""
         pending_tool_calls = []
 
+        # Agent loop protection config
+        agent_config = query.pipeline_config['ai']['local-agent']
+        max_tool_iterations = agent_config.get('max-tool-iterations', 16)
+        max_tool_result_chars = agent_config.get('max-tool-result-chars', 8000)
+        iteration_count = 0
+
         # Get knowledge bases list (new field)
         kb_uuids = query.pipeline_config['ai']['local-agent'].get('knowledge-bases', [])
 
@@ -119,51 +216,51 @@ class LocalAgentRunner(runner.RequestRunner):
 
         remove_think = query.pipeline_config['output'].get('misc', '').get('remove-think')
 
-        use_llm_model = await self.ap.model_mgr.get_model_by_uuid(query.use_llm_model_uuid)
+        # Build ordered candidate list (primary + fallbacks)
+        candidates = await self._get_model_candidates(query)
+        if not candidates:
+            raise RuntimeError('No LLM model configured for local-agent runner')
 
         self.ap.logger.debug(
-            f'localagent req: query={query.query_id} req_messages={req_messages} use_llm_model={query.use_llm_model_uuid}'
+            f'localagent req: query={query.query_id} req_messages={req_messages} '
+            f'candidates={[m.model_entity.name for m in candidates]}'
         )
 
         if not is_stream:
-            # 非流式输出，直接请求
+            # Non-streaming: invoke with fallback
-
+            msg, use_llm_model = await self._invoke_with_fallback(
-            msg = await use_llm_model.provider.invoke_llm(
                 query,
-                use_llm_model,
+                candidates,
                 req_messages,
                 query.use_funcs,
-                extra_args=use_llm_model.model_entity.extra_args,
+                remove_think,
-                remove_think=remove_think,
             )
             yield msg
             final_msg = msg
         else:
-            # 流式输出，需要处理工具调用
+            # Streaming: invoke with fallback
             tool_calls_map: dict[str, provider_message.ToolCall] = {}
             msg_idx = 0
-            accumulated_content = ''  # 从开始累积的所有内容
+            accumulated_content = ''
             last_role = 'assistant'
             msg_sequence = 1
-            async for msg in use_llm_model.provider.invoke_llm_stream(
+
+            stream_src, use_llm_model = await self._invoke_stream_with_fallback(
                 query,
-                use_llm_model,
+                candidates,
                 req_messages,
                 query.use_funcs,
-                extra_args=use_llm_model.model_entity.extra_args,
+                remove_think,
-                remove_think=remove_think,
+            )
-            ):
+            async for msg in stream_src:
                 msg_idx = msg_idx + 1
 
-                # 记录角色
                 if msg.role:
                     last_role = msg.role
 
-                # 累积内容
                 if msg.content:
                     accumulated_content += msg.content
 
-                # 处理工具调用
                 if msg.tool_calls:
                     for tool_call in msg.tool_calls:
                         if tool_call.id not in tool_calls_map:
@@ -175,21 +272,18 @@ class LocalAgentRunner(runner.RequestRunner):
                                 ),
                             )
                         if tool_call.function and tool_call.function.arguments:
-                            # 流式处理中，工具调用参数可能分多个chunk返回，需要追加而不是覆盖
                             tool_calls_map[tool_call.id].function.arguments += tool_call.function.arguments
-                # continue
+
-                # 每8个chunk或最后一个chunk时，输出所有累积的内容
                 if msg_idx % 8 == 0 or msg.is_final:
                     msg_sequence += 1
                     yield provider_message.MessageChunk(
                         role=last_role,
-                        content=accumulated_content,  # 输出所有累积内容
+                        content=accumulated_content,
                         tool_calls=list(tool_calls_map.values()) if (tool_calls_map and msg.is_final) else None,
                         is_final=msg.is_final,
                         msg_sequence=msg_sequence,
                     )
 
-            # 创建最终消息用于后续处理
             final_msg = provider_message.MessageChunk(
                 role=last_role,
                 content=accumulated_content,
@@ -204,8 +298,17 @@ class LocalAgentRunner(runner.RequestRunner):
 
         req_messages.append(final_msg)
 
-        # 持续请求，只要还有待处理的工具调用就继续处理调用
+        # Once a model succeeds, commit to it for the tool call loop
+        # (no fallback mid-conversation — different models may interpret tool results differently)
         while pending_tool_calls:
+            iteration_count += 1
+            if iteration_count > max_tool_iterations:
+                self.ap.logger.warning(
+                    f'localagent: query={query.query_id} agent loop exceeded max iterations ({max_tool_iterations}), '
+                    f'forcing termination'
+                )
+                break
+
             for tool_call in pending_tool_calls:
                 try:
                     func = tool_call.function
@@ -228,6 +331,14 @@ class LocalAgentRunner(runner.RequestRunner):
                     else:
                         tool_content = json.dumps(func_ret, ensure_ascii=False)
 
+                    # Truncate oversized tool results to prevent context overflow
+                    if isinstance(tool_content, str) and len(tool_content) > max_tool_result_chars:
+                        self.ap.logger.warning(
+                            f'localagent: tool {func.name} returned {len(tool_content)} chars, '
+                            f'truncating to {max_tool_result_chars}'
+                        )
+                        tool_content = tool_content[:max_tool_result_chars] + '\n...[result truncated]'
+
                     if is_stream:
                         msg = provider_message.MessageChunk(
                             role='tool',
@@ -245,7 +356,6 @@ class LocalAgentRunner(runner.RequestRunner):
 
                     req_messages.append(msg)
                 except Exception as e:
-                    # 工具调用出错，添加一个报错信息到 req_messages
                     err_msg = provider_message.Message(role='tool', content=f'err: {e}', tool_call_id=tool_call.id)
 
                     yield err_msg
@@ -253,39 +363,38 @@ class LocalAgentRunner(runner.RequestRunner):
                     req_messages.append(err_msg)
 
             self.ap.logger.debug(
-                f'localagent req: query={query.query_id} req_messages={req_messages} use_llm_model={query.use_llm_model_uuid}'
+                f'localagent req: query={query.query_id} req_messages={req_messages} '
+                f'use_llm_model={use_llm_model.model_entity.name}'
             )
 
             if is_stream:
                 tool_calls_map = {}
                 msg_idx = 0
-                accumulated_content = ''  # 从开始累积的所有内容
+                accumulated_content = ''
                 last_role = 'assistant'
                 msg_sequence = first_end_sequence
 
-                async for msg in use_llm_model.provider.invoke_llm_stream(
+                tool_stream_src = use_llm_model.provider.invoke_llm_stream(
                     query,
                     use_llm_model,
                     req_messages,
-                    query.use_funcs,
+                    query.use_funcs if use_llm_model.model_entity.abilities.__contains__('func_call') else [],
                     extra_args=use_llm_model.model_entity.extra_args,
                     remove_think=remove_think,
-                ):
+                )
+                async for msg in tool_stream_src:
                     msg_idx += 1
 
-                    # 记录角色
                     if msg.role:
                         last_role = msg.role
 
-                    # 第一次请求工具调用时的内容
+                    # Prepend first-round content on first chunk of tool-call round
                     if msg_idx == 1:
                         accumulated_content = first_content if first_content is not None else accumulated_content
 
-                    # 累积内容
                     if msg.content:
                         accumulated_content += msg.content
 
-                    # 处理工具调用
                     if msg.tool_calls:
                         for tool_call in msg.tool_calls:
                             if tool_call.id not in tool_calls_map:
@@ -297,15 +406,13 @@ class LocalAgentRunner(runner.RequestRunner):
                                     ),
                                 )
                             if tool_call.function and tool_call.function.arguments:
-                                # 流式处理中，工具调用参数可能分多个chunk返回，需要追加而不是覆盖
                                 tool_calls_map[tool_call.id].function.arguments += tool_call.function.arguments
 
-                    # 每8个chunk或最后一个chunk时，输出所有累积的内容
                     if msg_idx % 8 == 0 or msg.is_final:
                         msg_sequence += 1
                         yield provider_message.MessageChunk(
                             role=last_role,
-                            content=accumulated_content,  # 输出所有累积内容
+                            content=accumulated_content,
                             tool_calls=list(tool_calls_map.values()) if (tool_calls_map and msg.is_final) else None,
                             is_final=msg.is_final,
                             msg_sequence=msg_sequence,
@@ -318,12 +425,12 @@ class LocalAgentRunner(runner.RequestRunner):
                     msg_sequence=msg_sequence,
                 )
             else:
-                # 处理完所有调用，再次请求
+                # Non-streaming: use committed model directly (no fallback in tool loop)
                 msg = await use_llm_model.provider.invoke_llm(
                     query,
                     use_llm_model,
                     req_messages,
-                    query.use_funcs,
+                    query.use_funcs if use_llm_model.model_entity.abilities.__contains__('func_call') else [],
                     extra_args=use_llm_model.model_entity.extra_args,
                     remove_think=remove_think,
                 )

src/langbot/pkg/utils/constants.py

@@ -2,7 +2,7 @@ import langbot
 
 semantic_version = f'v{langbot.__version__}'
 
-required_database_version = 22
+required_database_version = 23
 """Tag the version of the database schema, used to check if the database needs to be migrated"""
 
 debug_mode = False

src/langbot/templates/metadata/pipeline/ai.yaml

@@ -59,8 +59,11 @@ stages:
         label:
           en_US: Model
           zh_Hans: 模型
-        type: llm-model-selector
+        type: model-fallback-selector
         required: true
+        default:
+          primary: ''
+          fallbacks: []
       - name: max-round
         label:
           en_US: Max Round
@@ -90,6 +93,26 @@ stages:
         type: knowledge-base-multi-selector
         required: false
         default: []
+      - name: max-tool-iterations
+        label:
+          en_US: Max Tool Iterations
+          zh_Hans: 最大工具调用轮次
+        description:
+          en_US: Maximum number of tool call iterations in a single agent loop to prevent runaway loops
+          zh_Hans: 单次 Agent 循环中工具调用的最大轮次，防止无限循环
+        type: integer
+        required: false
+        default: 16
+      - name: max-tool-result-chars
+        label:
+          en_US: Max Tool Result Length
+          zh_Hans: 工具返回最大字符数
+        description:
+          en_US: Maximum character length of a single tool call result, longer results will be truncated
+          zh_Hans: 单次工具调用返回结果的最大字符数，超出部分将被截断
+        type: integer
+        required: false
+        default: 8000
   - name: tbox-app-api
     label:
       en_US: Tbox App API

web/src/app/home/bots/components/bot-form/BotForm.tsx

@@ -124,12 +124,6 @@ export default function BotForm({
   const currentAdapter = form.watch('adapter');
   const currentAdapterConfig = form.watch('adapter_config');
 
-  // Serialize adapter_config to a stable string so it can be used as a
-  // useEffect dependency without triggering on every render.  form.watch()
-  // returns a new object reference each time, which would otherwise cause
-  // the filtering effect below to loop indefinitely.
-  const adapterConfigJson = JSON.stringify(currentAdapterConfig);
-
   useEffect(() => {
     setBotFormValues();
   }, []);
@@ -153,7 +147,7 @@ export default function BotForm({
       // For non-Lark adapters, show all fields
       setFilteredDynamicFormConfigList(dynamicFormConfigList);
     }
-  }, [currentAdapter, adapterConfigJson, dynamicFormConfigList]);
+  }, [currentAdapter, currentAdapterConfig, dynamicFormConfigList]);
 
   // 复制到剪贴板的辅助函数 - 使用页面上的真实input元素
   const copyToClipboard = () => {

web/src/app/home/components/dynamic-form/DynamicFormComponent.tsx

@@ -11,7 +11,7 @@ import {
   FormMessage,
 } from '@/components/ui/form';
 import DynamicFormItemComponent from '@/app/home/components/dynamic-form/DynamicFormItemComponent';
-import { useCallback, useEffect, useRef } from 'react';
+import { useEffect, useRef } from 'react';
 import { extractI18nObject } from '@/i18n/I18nProvider';
 import { useTranslation } from 'react-i18next';
 
@@ -73,6 +73,12 @@ export default function DynamicFormComponent({
           case 'bot-selector':
             fieldSchema = z.string();
             break;
+          case 'model-fallback-selector':
+            fieldSchema = z.object({
+              primary: z.string(),
+              fallbacks: z.array(z.string()),
+            });
+            break;
           case 'prompt-editor':
             fieldSchema = z.array(
               z.object({
@@ -160,39 +166,34 @@ export default function DynamicFormComponent({
   const onSubmitRef = useRef(onSubmit);
   onSubmitRef.current = onSubmit;
 
-  // Track the last emitted values to avoid emitting identical snapshots,
+  // 监听表单值变化
-  // which would cause the parent to call setValue with an equivalent object,
+  useEffect(() => {
-  // triggering a re-render loop.
+    // Emit initial form values immediately so the parent always has a valid snapshot,
-  const lastEmittedRef = useRef<string>('');
+    // even if the user saves without modifying any field.
-
+    // form.watch(callback) only fires on subsequent changes, not on mount.
-  const emitValues = useCallback(() => {
     const formValues = form.getValues();
-    const finalValues = itemConfigList.reduce(
+    const initialFinalValues = itemConfigList.reduce(
       (acc, item) => {
         acc[item.name] = formValues[item.name] ?? item.default;
         return acc;
       },
       {} as Record<string, object>,
     );
-    const serialized = JSON.stringify(finalValues);
+    onSubmitRef.current?.(initialFinalValues);
-    if (serialized !== lastEmittedRef.current) {
-      lastEmittedRef.current = serialized;
-      onSubmitRef.current?.(finalValues);
-    }
-  }, [form, itemConfigList]);
-
-  // 监听表单值变化
-  useEffect(() => {
-    // Emit initial form values immediately so the parent always has a valid snapshot,
-    // even if the user saves without modifying any field.
-    // form.watch(callback) only fires on subsequent changes, not on mount.
-    emitValues();
 
     const subscription = form.watch(() => {
-      emitValues();
+      const formValues = form.getValues();
+      const finalValues = itemConfigList.reduce(
+        (acc, item) => {
+          acc[item.name] = formValues[item.name] ?? item.default;
+          return acc;
+        },
+        {} as Record<string, object>,
+      );
+      onSubmitRef.current?.(finalValues);
     });
     return () => subscription.unsubscribe();
-  }, [form, itemConfigList, emitValues]);
+  }, [form, itemConfigList]);
 
   return (
     <Form {...form}>
@@ -231,6 +232,7 @@ export default function DynamicFormComponent({
 
           // All fields are disabled when editing (creation_settings are immutable)
           const isFieldDisabled = !!isEditing;
+
           return (
             <FormField
               key={config.id}

web/src/app/home/components/dynamic-form/DynamicFormItemComponent.tsx

@@ -124,6 +124,28 @@ export default function DynamicFormItemComponent({
     }
   }, [config.type]);
 
+  useEffect(() => {
+    if (config.type === DynamicFormItemType.MODEL_FALLBACK_SELECTOR) {
+      httpClient
+        .getProviderLLMModels()
+        .then((resp) => {
+          let models = resp.models;
+          if (
+            systemInfo.disable_models_service ||
+            userInfo?.account_type !== 'space'
+          ) {
+            models = models.filter(
+              (m) => m.provider?.requester !== 'space-chat-completions',
+            );
+          }
+          setLlmModels(models);
+        })
+        .catch((err) => {
+          toast.error('Failed to get LLM model list: ' + err.msg);
+        });
+    }
+  }, [config.type]);
+
   useEffect(() => {
     if (
       config.type === DynamicFormItemType.KNOWLEDGE_BASE_SELECTOR ||
@@ -171,12 +193,7 @@ export default function DynamicFormItemComponent({
       return <Textarea {...field} className="min-h-[120px]" />;
 
     case DynamicFormItemType.BOOLEAN:
-      return (
+      return <Switch checked={field.value} onCheckedChange={field.onChange} />;
-        <Switch
-          checked={field.value ?? false}
-          onCheckedChange={field.onChange}
-        />
-      );
 
     case DynamicFormItemType.STRING_ARRAY:
       return (
@@ -227,7 +244,7 @@ export default function DynamicFormItemComponent({
 
     case DynamicFormItemType.SELECT:
       return (
-        <Select value={field.value ?? ''} onValueChange={field.onChange}>
+        <Select value={field.value} onValueChange={field.onChange}>
           <SelectTrigger className="bg-[#ffffff] dark:bg-[#2a2a2e]">
             <SelectValue placeholder={t('common.select')} />
           </SelectTrigger>
@@ -318,6 +335,172 @@ export default function DynamicFormItemComponent({
         </Select>
       );
 
+    case DynamicFormItemType.MODEL_FALLBACK_SELECTOR: {
+      // Group models by provider
+      const groupedModelsForFallback = llmModels.reduce(
+        (acc, model) => {
+          const providerName =
+            model.provider?.name || model.provider?.requester || 'Unknown';
+          if (!acc[providerName]) acc[providerName] = [];
+          acc[providerName].push(model);
+          return acc;
+        },
+        {} as Record<string, LLMModel[]>,
+      );
+
+      const modelValue = field.value as {
+        primary: string;
+        fallbacks: string[];
+      };
+
+      const renderModelSelect = (
+        value: string,
+        onChange: (val: string) => void,
+        placeholder: string,
+      ) => (
+        <Select value={value} onValueChange={onChange}>
+          <SelectTrigger className="bg-[#ffffff] dark:bg-[#2a2a2e]">
+            <SelectValue placeholder={placeholder} />
+          </SelectTrigger>
+          <SelectContent>
+            {Object.entries(groupedModelsForFallback).map(
+              ([providerName, models]) => (
+                <SelectGroup key={providerName}>
+                  <SelectLabel>{providerName}</SelectLabel>
+                  {models.map((model) => (
+                    <SelectItem key={model.uuid} value={model.uuid}>
+                      <span className="inline-flex items-center gap-1">
+                        {model.name}
+                        {model.abilities?.includes('vision') && (
+                          <Eye className="h-3 w-3 text-muted-foreground" />
+                        )}
+                        {model.abilities?.includes('func_call') && (
+                          <Wrench className="h-3 w-3 text-muted-foreground" />
+                        )}
+                      </span>
+                    </SelectItem>
+                  ))}
+                </SelectGroup>
+              ),
+            )}
+          </SelectContent>
+        </Select>
+      );
+
+      const updateValue = (patch: Partial<typeof modelValue>) => {
+        field.onChange({ ...modelValue, ...patch });
+      };
+
+      const addFallbackModel = () => {
+        updateValue({ fallbacks: [...modelValue.fallbacks, ''] });
+      };
+
+      const updateFallbackModel = (index: number, value: string) => {
+        const updated = [...modelValue.fallbacks];
+        updated[index] = value;
+        updateValue({ fallbacks: updated });
+      };
+
+      const removeFallbackModel = (index: number) => {
+        const updated = [...modelValue.fallbacks];
+        updated.splice(index, 1);
+        updateValue({ fallbacks: updated });
+      };
+
+      const moveFallbackModel = (index: number, direction: 'up' | 'down') => {
+        const updated = [...modelValue.fallbacks];
+        const newIndex = direction === 'up' ? index - 1 : index + 1;
+        if (newIndex < 0 || newIndex >= updated.length) return;
+        [updated[index], updated[newIndex]] = [
+          updated[newIndex],
+          updated[index],
+        ];
+        updateValue({ fallbacks: updated });
+      };
+
+      return (
+        <div className="space-y-3">
+          {/* Primary model selector */}
+          <div>
+            <p className="text-xs text-muted-foreground mb-1">
+              {t('models.fallback.primary')}
+            </p>
+            {renderModelSelect(
+              modelValue.primary,
+              (val) => updateValue({ primary: val }),
+              t('models.selectModel'),
+            )}
+          </div>
+
+          {/* Fallback models */}
+          {modelValue.fallbacks.length > 0 && (
+            <div className="space-y-2">
+              <p className="text-xs text-muted-foreground">
+                {t('models.fallback.fallbackList')}
+              </p>
+              {modelValue.fallbacks.map((fbUuid: string, index: number) => (
+                <div key={index} className="flex items-center gap-2">
+                  <span className="text-xs text-muted-foreground w-4 shrink-0">
+                    {index + 1}.
+                  </span>
+                  <div className="flex-1">
+                    {renderModelSelect(
+                      fbUuid,
+                      (val) => updateFallbackModel(index, val),
+                      t('models.selectModel'),
+                    )}
+                  </div>
+                  <div className="flex gap-1 shrink-0">
+                    <Button
+                      type="button"
+                      variant="ghost"
+                      size="sm"
+                      className="h-8 w-8 p-0"
+                      onClick={() => moveFallbackModel(index, 'up')}
+                      disabled={index === 0}
+                    >
+                      ↑
+                    </Button>
+                    <Button
+                      type="button"
+                      variant="ghost"
+                      size="sm"
+                      className="h-8 w-8 p-0"
+                      onClick={() => moveFallbackModel(index, 'down')}
+                      disabled={index === modelValue.fallbacks.length - 1}
+                    >
+                      ↓
+                    </Button>
+                    <Button
+                      type="button"
+                      variant="ghost"
+                      size="sm"
+                      className="h-8 w-8 p-0 text-destructive"
+                      onClick={() => removeFallbackModel(index)}
+                    >
+                      <X className="h-4 w-4" />
+                    </Button>
+                  </div>
+                </div>
+              ))}
+            </div>
+          )}
+
+          {/* Add fallback button */}
+          <Button
+            type="button"
+            variant="outline"
+            size="sm"
+            className="w-full"
+            onClick={addFallbackModel}
+          >
+            <Plus className="h-4 w-4 mr-1" />
+            {t('models.fallback.addFallback')}
+          </Button>
+        </div>
+      );
+    }
+
     case DynamicFormItemType.KNOWLEDGE_BASE_SELECTOR:
       // Group KBs by Knowledge Engine name
       const kbsByEngine = knowledgeBases.reduce(

web/src/app/home/components/models-dialog/ModelsDialog.tsx

@@ -463,14 +463,16 @@ export default function ModelsDialog({
                     )
                   : t('models.providerCount', { count: otherProviders.length })}
               </span>
-              <Button
+              <div className="flex gap-2">
-                size="sm"
+                <Button
-                variant="outline"
+                  size="sm"
-                onClick={handleCreateProvider}
+                  variant="outline"
-              >
+                  onClick={handleCreateProvider}
-                <Plus className="h-4 w-4 mr-1" />
+                >
-                {t('models.addProvider')}
+                  <Plus className="h-4 w-4 mr-1" />
-              </Button>
+                  {t('models.addProvider')}
+                </Button>
+              </div>
             </div>
 
             {/* Provider List */}

web/src/app/home/plugins/components/plugin-market/PluginMarketComponent.tsx

@@ -1,13 +1,6 @@
 'use client';
 
-import {
+import { useState, useEffect, useCallback, useRef, Suspense } from 'react';
-  useState,
-  useEffect,
-  useCallback,
-  useRef,
-  Suspense,
-  useMemo,
-} from 'react';
 import { Input } from '@/components/ui/input';
 import {
   Select,
@@ -70,7 +63,7 @@ function MarketPageContent({
     RecommendationList[]
   >([]);
 
-  const pageSize = 16; // 每页16个，4行x4列
+  const pageSize = 12; // 每页12个
   const searchTimeoutRef = useRef<NodeJS.Timeout | null>(null);
   const scrollContainerRef = useRef<HTMLDivElement | null>(null);
 
@@ -330,38 +323,7 @@ function MarketPageContent({
     };
   }, []);
 
-  // 计算所有推荐插件的 ID 集合
+  const visiblePlugins = plugins;
-  const recommendedPluginIds = useMemo(() => {
-    const ids = new Set<string>();
-    recommendationLists.forEach((list) => {
-      list.plugins.forEach((plugin) => {
-        ids.add(`${plugin.author} / ${plugin.name}`);
-      });
-    });
-    return ids;
-  }, [recommendationLists]);
-
-  // 过滤掉已在推荐列表中展示的插件
-  // 仅在显示推荐列表的条件下（无搜索、无筛选、第一页或后续页的累积数据中）进行过滤
-  // 注意：如果用户翻页，我们希望一直保持去重，否则推荐过的插件会在第二页出现
-  // 但是推荐列表只在第一页且无筛选时显示。
-  // 如果用户进行了筛选/搜索，推荐列表不显示，此时不需要去重。
-  const visiblePlugins = useMemo(() => {
-    const showRecommendations =
-      !searchQuery && componentFilter === 'all' && selectedTags.length === 0;
-
-    if (!showRecommendations) {
-      return plugins;
-    }
-
-    return plugins.filter((p) => !recommendedPluginIds.has(p.pluginId));
-  }, [
-    plugins,
-    recommendedPluginIds,
-    searchQuery,
-    componentFilter,
-    selectedTags,
-  ]);
 
   // 加载更多
   const loadMore = useCallback(() => {

web/src/app/home/plugins/components/plugin-market/RecommendationLists.tsx

@@ -47,10 +47,12 @@ function RecommendationListRow({
   list,
   tagNames,
   onInstall,
+  isLast,
 }: {
   list: RecommendationList;
   tagNames: Record<string, string>;
   onInstall: (author: string, pluginName: string) => void;
+  isLast: boolean;
 }) {
   const { t } = useTranslation();
   const [page, setPage] = useState(0);
@@ -143,7 +145,9 @@ function RecommendationListRow({
           />
         ))}
       </div>
-      {totalPages > 1 && <div className="border-b border-border mt-6" />}
+      {totalPages > 1 && !isLast && (
+        <div className="border-b border-border mt-6" />
+      )}
     </div>
   );
 }
@@ -161,12 +165,13 @@ export function RecommendationLists({
 
   return (
     <div className="mt-6">
-      {lists.map((list) => (
+      {lists.map((list, index) => (
         <RecommendationListRow
           key={list.uuid}
           list={list}
           tagNames={tagNames}
           onInstall={onInstall}
+          isLast={index === lists.length - 1}
         />
       ))}
       <div className="border-b border-border mb-6" />

web/src/app/home/plugins/components/plugin-market/plugin-market-card/PluginMarketCardComponent.tsx

@@ -17,7 +17,7 @@ import {
   FileText,
   Info,
 } from 'lucide-react';
-import { useState } from 'react';
+import { useState, useRef, useEffect } from 'react';
 import { Button } from '@/components/ui/button';
 
 export default function PluginMarketCardComponent({
@@ -31,6 +31,43 @@ export default function PluginMarketCardComponent({
 }) {
   const { t } = useTranslation();
   const [isHovered, setIsHovered] = useState(false);
+  const bottomRef = useRef<HTMLDivElement>(null);
+  const [visibleTags, setVisibleTags] = useState(2);
+
+  // Measure how many tags fit in the bottom row
+  useEffect(() => {
+    const tags = cardVO.tags;
+    if (!bottomRef.current || !tags || tags.length === 0) return;
+
+    const measure = () => {
+      const container = bottomRef.current;
+      if (!container) return;
+      const width = container.offsetWidth;
+      const availableForTags = width - 140 - 80;
+      if (availableForTags <= 0) {
+        setVisibleTags(0);
+        return;
+      }
+      const tagWidth = 80;
+      const plusBadgeWidth = 40;
+      const maxTags = Math.max(
+        0,
+        Math.floor((availableForTags - plusBadgeWidth) / tagWidth),
+      );
+      if (maxTags >= tags.length) {
+        setVisibleTags(tags.length);
+      } else {
+        setVisibleTags(Math.max(1, maxTags));
+      }
+    };
+
+    measure();
+    const observer = new ResizeObserver(measure);
+    observer.observe(bottomRef.current);
+    return () => observer.disconnect();
+  }, [cardVO.tags]);
+
+  const remainingTags = cardVO.tags ? cardVO.tags.length - visibleTags : 0;
 
   function handleInstallClick(e: React.MouseEvent) {
     e.stopPropagation();
@@ -135,10 +172,13 @@ export default function PluginMarketCardComponent({
         </div>
 
         {/* 下部分：下载量、标签和组件列表 */}
-        <div className="w-full flex flex-row items-center justify-between gap-2 px-0 sm:px-[0.4rem] flex-shrink-0">
+        <div
-          <div className="flex flex-row items-center justify-start gap-2 flex-wrap">
+          ref={bottomRef}
+          className="w-full flex flex-row items-center justify-between gap-2 px-0 sm:px-[0.4rem] flex-shrink-0 overflow-hidden"
+        >
+          <div className="flex flex-row items-center justify-start gap-2 min-w-0 overflow-hidden">
             {/* 下载数量 */}
-            <div className="flex flex-row items-center gap-[0.3rem] sm:gap-[0.4rem]">
+            <div className="flex flex-row items-center gap-[0.3rem] sm:gap-[0.4rem] flex-shrink-0">
               <svg
                 className="w-4 h-4 sm:w-[1.2rem] sm:h-[1.2rem] text-[#2563eb] dark:text-[#5b8def] flex-shrink-0"
                 xmlns="http://www.w3.org/2000/svg"
@@ -156,14 +196,14 @@ export default function PluginMarketCardComponent({
               </div>
             </div>
 
-            {/* Tags */}
+            {/* Tags - adaptive */}
-            {cardVO.tags && cardVO.tags.length > 0 && (
+            {cardVO.tags && cardVO.tags.length > 0 && visibleTags > 0 && (
-              <div className="flex flex-wrap gap-1.5">
+              <div className="flex flex-row items-center gap-1.5 overflow-hidden flex-shrink min-w-0">
-                {cardVO.tags.slice(0, 2).map((tag) => (
+                {cardVO.tags.slice(0, visibleTags).map((tag) => (
                   <Badge
                     key={tag}
                     variant="secondary"
-                    className="text-[0.65rem] sm:text-[0.7rem] px-2 py-0.5 h-5 flex items-center gap-1 flex-shrink-0"
+                    className="text-[0.65rem] sm:text-[0.7rem] px-2 py-0.5 h-5 flex items-center gap-1 flex-shrink-0 whitespace-nowrap"
                   >
                     <svg
                       className="w-2.5 h-2.5 flex-shrink-0"
@@ -178,15 +218,17 @@ export default function PluginMarketCardComponent({
                       <path d="M20.59 13.41l-7.17 7.17a2 2 0 0 1-2.83 0L2 12V2h10l8.59 8.59a2 2 0 0 1 0 2.82z" />
                       <line x1="7" y1="7" x2="7.01" y2="7" />
                     </svg>
-                    <span className="truncate">{tagNames[tag] || tag}</span>
+                    <span className="truncate max-w-[5rem]">
+                      {tagNames[tag] || tag}
+                    </span>
                   </Badge>
                 ))}
-                {cardVO.tags.length > 2 && (
+                {remainingTags > 0 && (
                   <Badge
                     variant="outline"
-                    className="text-[0.65rem] sm:text-[0.7rem] px-2 py-0.5 h-5 flex items-center flex-shrink-0"
+                    className="text-[0.65rem] sm:text-[0.7rem] px-1.5 py-0.5 h-5 flex items-center flex-shrink-0 whitespace-nowrap"
                   >
-                    +{cardVO.tags.length - 2}
+                    +{remainingTags}
                   </Badge>
                 )}
               </div>

web/src/app/infra/entities/form/dynamic.ts

@@ -35,6 +35,7 @@ export enum DynamicFormItemType {
   SELECT = 'select',
   LLM_MODEL_SELECTOR = 'llm-model-selector',
   EMBEDDING_MODEL_SELECTOR = 'embedding-model-selector',
+  MODEL_FALLBACK_SELECTOR = 'model-fallback-selector',
   PROMPT_EDITOR = 'prompt-editor',
   UNKNOWN = 'unknown',
   KNOWLEDGE_BASE_SELECTOR = 'knowledge-base-selector',

web/src/i18n/locales/en-US.ts

@@ -236,6 +236,11 @@ const enUS = {
     modelsCount: '{{count}} model(s)',
     expandModels: 'Expand',
     collapseModels: 'Collapse',
+    fallback: {
+      primary: 'Primary Model',
+      fallbackList: 'Fallback Models',
+      addFallback: 'Add Fallback Model',
+    },
   },
   bots: {
     title: 'Bots',

web/src/i18n/locales/ja-JP.ts

@@ -1,4 +1,4 @@
-const jaJP = {
+const jaJP = {
   common: {
     login: 'ログイン',
     logout: 'ログアウト',
@@ -241,6 +241,11 @@ const jaJP = {
     modelsCount: '{{count}} 個のモデル',
     expandModels: '展開',
     collapseModels: '折りたたむ',
+    fallback: {
+      primary: 'プライマリモデル',
+      fallbackList: 'フォールバックモデル',
+      addFallback: 'フォールバックモデルを追加',
+    },
   },
   bots: {
     title: 'ボット',

web/src/i18n/locales/zh-Hans.ts

@@ -227,6 +227,11 @@ const zhHans = {
     modelsCount: '{{count}} 个模型',
     expandModels: '展开',
     collapseModels: '收起',
+    fallback: {
+      primary: '主模型',
+      fallbackList: '备用模型',
+      addFallback: '添加备用模型',
+    },
   },
   bots: {
     title: '机器人',

web/src/i18n/locales/zh-Hant.ts

@@ -226,6 +226,11 @@ const zhHant = {
     modelsCount: '{{count}} 個模型',
     expandModels: '展開',
     collapseModels: '收起',
+    fallback: {
+      primary: '主模型',
+      fallbackList: '備用模型',
+      addFallback: '新增備用模型',
+    },
   },
   bots: {
     title: '機器人',