feat(web): add first-token timeout to the workflow model parameter panel

Append a synthetic FIRST_TOKEN_TIMEOUT_PARAMETER_RULE (int, seconds, opt-in)
to the model parameter panel, mirroring how the stop rule is injected. The
rule renders only in workflow advanced mode (isInWorkflow), covering the LLM,
question classifier and parameter extractor panels; easy-UI app orchestration
pages never show it. The value is stored in completion_params and consumed by
the Dify backend before the request reaches the provider.

web/app/components/header/account-setting/model-provider-page/model-parameter-modal/__tests__/index.spec.tsx

@@ -388,6 +388,23 @@ describe('ModelParameterModal', () => {
     expect(screen.getByText(/debugAsSingleModel/i)).toBeInTheDocument()
   })
 
+  it('should append the first token timeout parameter only in workflow advanced mode', () => {
+    render(<ModelParameterModal {...defaultProps} isAdvancedMode isInWorkflow />)
+
+    openSettings()
+
+    expect(screen.getByTestId('param-first_token_timeout')).toBeInTheDocument()
+  })
+
+  it('should not append the first token timeout parameter outside workflow', () => {
+    render(<ModelParameterModal {...defaultProps} isAdvancedMode />)
+
+    openSettings()
+
+    expect(screen.getByTestId('param-stop')).toBeInTheDocument()
+    expect(screen.queryByTestId('param-first_token_timeout')).not.toBeInTheDocument()
+  })
+
   it('should render the empty loading fallback when rules resolve to an empty list', () => {
     parameterRules = []
     isRulesLoading = true

web/app/components/header/account-setting/model-provider-page/model-parameter-modal/index.tsx

@@ -9,7 +9,11 @@ import { useMemo, useState } from 'react'
 import { useTranslation } from 'react-i18next'
 import { ArrowNarrowLeft } from '@/app/components/base/icons/src/vender/line/arrows'
 import Loading from '@/app/components/base/loading'
-import { PROVIDER_WITH_PRESET_TONE, STOP_PARAMETER_RULE } from '@/config'
+import {
+  FIRST_TOKEN_TIMEOUT_PARAMETER_RULE,
+  PROVIDER_WITH_PRESET_TONE,
+  STOP_PARAMETER_RULE,
+} from '@/config'
 import { useModelParameterRules } from '@/service/use-common'
 import { useTextGenerationCurrentProviderAndModelAndModelList } from '../hooks'
 import ModelSelector from '../model-selector'
@@ -216,22 +220,24 @@ const ModelParameterModal: FC<ModelParameterModalProps> = ({
                   <Loading />
                 </div>
               ) : (
-                [...parameterRules, ...(isAdvancedMode ? [STOP_PARAMETER_RULE] : [])].map(
-                  (parameter) => (
-                    <ParameterItem
-                      key={`${modelId}-${parameter.name}`}
-                      parameterRule={parameter}
-                      value={completionParams?.[parameter.name]}
-                      onChange={(v) => handleParamChange(parameter.name, v)}
-                      onSwitch={(checked, assignValue) =>
-                        handleSwitch(parameter.name, checked, assignValue)
-                      }
-                      isInWorkflow={isInWorkflow}
-                      nodesOutputVars={nodesOutputVars}
-                      availableNodes={availableNodes}
-                    />
-                  ),
-                )
+                [
+                  ...parameterRules,
+                  ...(isAdvancedMode ? [STOP_PARAMETER_RULE] : []),
+                  ...(isAdvancedMode && isInWorkflow ? [FIRST_TOKEN_TIMEOUT_PARAMETER_RULE] : []),
+                ].map((parameter) => (
+                  <ParameterItem
+                    key={`${modelId}-${parameter.name}`}
+                    parameterRule={parameter}
+                    value={completionParams?.[parameter.name]}
+                    onChange={(v) => handleParamChange(parameter.name, v)}
+                    onSwitch={(checked, assignValue) =>
+                      handleSwitch(parameter.name, checked, assignValue)
+                    }
+                    isInWorkflow={isInWorkflow}
+                    nodesOutputVars={nodesOutputVars}
+                    availableNodes={availableNodes}
+                  />
+                ))
               )}
             </div>
           )}

web/config/index.ts

@@ -328,6 +328,27 @@ export const STOP_PARAMETER_RULE: ModelParameterRule = {
   },
 }
 
+// Synthetic rule consumed by the Dify backend before the request reaches the
+// model provider; only enforced for workflow LLM-compatible nodes.
+export const FIRST_TOKEN_TIMEOUT_PARAMETER_RULE: ModelParameterRule = {
+  default: 60,
+  min: 1,
+  max: 1800,
+  precision: 0,
+  help: {
+    en_US:
+      'Max seconds to wait for the first streamed token. On timeout the node fails; combine with node retry to re-run it automatically.',
+    zh_Hans: '等待首个流式 Token 的最长秒数。超时后节点失败，可配合节点重试自动重跑。',
+  },
+  label: {
+    en_US: 'First token timeout',
+    zh_Hans: '首个 Token 超时',
+  },
+  name: 'first_token_timeout',
+  required: false,
+  type: 'int',
+}
+
 export const PARTNER_STACK_CONFIG = {
   cookieName: 'partner_stack_info',
   saveCookieDays: 90,