diff --git a/src/commands/provider/provider.test.tsx b/src/commands/provider/provider.test.tsx
index 12113f11..bde1822c 100644
--- a/src/commands/provider/provider.test.tsx
+++ b/src/commands/provider/provider.test.tsx
@@ -11,6 +11,7 @@ import {
   buildCodexOAuthProfileEnv,
   buildCurrentProviderSummary,
   buildProfileSaveMessage,
+  buildProviderManagerCompletion,
   getProviderWizardDefaults,
   ProviderWizard,
   TextEntryDialog,
@@ -264,6 +265,32 @@ test('wizard step remount prevents a typed API key from leaking into the next fi
   expect(output).not.toContain('sk-secret-12345678')
 })
 
+test('buildProviderManagerCompletion records provider switch event and model-visible reminder', () => {
+  const completion = buildProviderManagerCompletion({
+    action: 'activated',
+    activeProviderName: 'Sadaf Provider',
+    activeProviderModel: 'sadaf-model',
+    message: 'Provider switched to Sadaf Provider (sadaf-model)',
+  })
+
+  expect(completion.message).toBe(
+    'Provider switched to Sadaf Provider (sadaf-model)',
+  )
+  expect(completion.metaMessages).toEqual([
+    '<system-reminder>Provider switched mid-session to Sadaf Provider using model sadaf-model. Use this provider/model for subsequent requests unless the user switches again.</system-reminder>',
+  ])
+})
+
+test('buildProviderManagerCompletion skips provider reminder when manager is cancelled', () => {
+  const completion = buildProviderManagerCompletion({
+    action: 'cancelled',
+    message: 'Provider manager closed',
+  })
+
+  expect(completion.message).toBe('Provider manager closed')
+  expect(completion.metaMessages).toBeUndefined()
+})
+
 test('buildProfileSaveMessage maps provider fields without echoing secrets', () => {
   const message = buildProfileSaveMessage(
     'openai',
diff --git a/src/commands/provider/provider.tsx b/src/commands/provider/provider.tsx
index 6d954d2a..db6de719 100644
--- a/src/commands/provider/provider.tsx
+++ b/src/commands/provider/provider.tsx
@@ -2,7 +2,10 @@ import * as React from 'react'
 
 import type { LocalJSXCommandCall, LocalJSXCommandOnDone } from '../../types/command.js'
 import { COMMON_HELP_ARGS, COMMON_INFO_ARGS } from '../../constants/xml.js'
-import { ProviderManager } from '../../components/ProviderManager.js'
+import {
+  ProviderManager,
+  type ProviderManagerResult,
+} from '../../components/ProviderManager.js'
 import TextInput from '../../components/TextInput.js'
 import {
   Select,
@@ -70,6 +73,29 @@ import {
   type OllamaGenerationReadiness,
 } from '../../utils/providerDiscovery.js'
 
+export function buildProviderManagerCompletion(result?: ProviderManagerResult): {
+  message: string
+  metaMessages?: string[]
+} {
+  const message =
+    result?.message ??
+    (result?.action === 'saved'
+      ? 'Provider profile updated'
+      : 'Provider manager closed')
+  const metaMessages =
+    result?.action === 'activated' && result.activeProviderName
+      ? [
+          `<system-reminder>Provider switched mid-session to ${result.activeProviderName}${
+            result.activeProviderModel
+              ? ` using model ${result.activeProviderModel}`
+              : ''
+          }. Use this provider/model for subsequent requests unless the user switches again.</system-reminder>`,
+        ]
+      : undefined
+
+  return { message, metaMessages }
+}
+
 function describeOllamaReadinessIssue(
   readiness: OllamaGenerationReadiness,
   options?: {
@@ -1703,13 +1729,8 @@ export const call: LocalJSXCommandCall = async (onDone, _context, args) => {
     <ProviderManager
       mode="manage"
       onDone={result => {
-        const message =
-          result?.message ??
-          (result?.action === 'saved'
-            ? 'Provider profile updated'
-            : 'Provider manager closed')
-
-        onDone(message, { display: 'system' })
+        const { message, metaMessages } = buildProviderManagerCompletion(result)
+        onDone(message, { display: 'system', metaMessages })
       }}
     />
   )
diff --git a/src/components/ProviderManager.tsx b/src/components/ProviderManager.tsx
index e72883e9..73c1bcde 100644
--- a/src/components/ProviderManager.tsx
+++ b/src/components/ProviderManager.tsx
@@ -58,8 +58,10 @@ import TextInput from './TextInput.js'
 import { useCodexOAuthFlow } from './useCodexOAuthFlow.js'
 
 export type ProviderManagerResult = {
-  action: 'saved' | 'cancelled'
+  action: 'saved' | 'cancelled' | 'activated'
   activeProfileId?: string
+  activeProviderName?: string
+  activeProviderModel?: string
   message?: string
 }
 
@@ -759,12 +761,14 @@ export function ProviderManager({ mode, onDone }: Props): React.ReactNode {
           mainLoopModelForSession: null,
         }))
         refreshProfiles()
-        setAppState(prev => ({
-          ...prev,
-          mainLoopModel: GITHUB_PROVIDER_DEFAULT_MODEL,
-        }))
         setStatusMessage(`Active provider: ${GITHUB_PROVIDER_LABEL}`)
         setIsActivating(false)
+        onDone({
+          action: 'activated',
+          activeProviderName: GITHUB_PROVIDER_LABEL,
+          activeProviderModel: GITHUB_PROVIDER_DEFAULT_MODEL,
+          message: `Provider switched to ${GITHUB_PROVIDER_LABEL} (${GITHUB_PROVIDER_DEFAULT_MODEL})`,
+        })
         returnToMenu()
         return
       }
@@ -799,23 +803,29 @@ export function ProviderManager({ mode, onDone }: Props): React.ReactNode {
         : null
 
       refreshProfiles()
-      setStatusMessage(
-        isActiveCodexOAuth
-          ? buildCodexOAuthActivationMessage({
-              prefix: `Active provider: ${active.name}`,
+      const activationMessage = isActiveCodexOAuth
+        ? buildCodexOAuthActivationMessage({
+            prefix: `Active provider: ${active.name}`,
+            activationWarning,
+            warnings: [
               activationWarning,
-              warnings: [
-                activationWarning,
-                settingsOverrideError
-                  ? `could not clear startup provider override (${settingsOverrideError})`
-                  : null,
-              ].filter((warning): warning is string => Boolean(warning)),
-            })
-          : settingsOverrideError
-            ? `Active provider: ${active.name}. Warning: could not clear startup provider override (${settingsOverrideError}).`
-            : `Active provider: ${active.name}`,
-      )
+              settingsOverrideError
+                ? `could not clear startup provider override (${settingsOverrideError})`
+                : null,
+            ].filter((warning): warning is string => Boolean(warning)),
+          })
+        : settingsOverrideError
+          ? `Active provider: ${active.name}. Warning: could not clear startup provider override (${settingsOverrideError}).`
+          : `Active provider: ${active.name}`
+      setStatusMessage(activationMessage)
       setIsActivating(false)
+      onDone({
+        action: 'activated',
+        activeProfileId: active.id,
+        activeProviderName: active.name,
+        activeProviderModel: newModel,
+        message: `Provider switched to ${active.name} (${newModel})`,
+      })
       returnToMenu()
     } catch (error) {
       refreshProfiles()
diff --git a/src/constants/promptIdentity.test.ts b/src/constants/promptIdentity.test.ts
index 818e7d0e..5c55041b 100644
--- a/src/constants/promptIdentity.test.ts
+++ b/src/constants/promptIdentity.test.ts
@@ -11,6 +11,7 @@ import { afterEach, expect, test } from 'bun:test'
   NATIVE_PACKAGE_URL: undefined,
 }
 
+import { clearSystemPromptSections } from './systemPromptSections.js'
 import { getSystemPrompt, DEFAULT_AGENT_PROMPT } from './prompts.js'
 import { CLI_SYSPROMPT_PREFIXES, getCLISyspromptPrefix } from './system.js'
 import { CLAUDE_CODE_GUIDE_AGENT } from '../tools/AgentTool/built-in/claudeCodeGuideAgent.js'
@@ -23,6 +24,7 @@ const originalSimpleEnv = process.env.CLAUDE_CODE_SIMPLE
 
 afterEach(() => {
   process.env.CLAUDE_CODE_SIMPLE = originalSimpleEnv
+  clearSystemPromptSections()
 })
 
 test('CLI identity prefixes describe OpenClaude instead of Claude Code', () => {
@@ -47,6 +49,21 @@ test('simple mode identity describes OpenClaude instead of Claude Code', async (
   expect(prompt[0]).not.toContain("Anthropic's official CLI for Claude")
 })
 
+test('system prompt model identity updates when model changes mid-session', async () => {
+  delete process.env.CLAUDE_CODE_SIMPLE
+  clearSystemPromptSections()
+
+  const firstPrompt = await getSystemPrompt([], 'old-test-model')
+  const secondPrompt = await getSystemPrompt([], 'new-test-model')
+
+  const firstText = firstPrompt.join('\n')
+  const secondText = secondPrompt.join('\n')
+
+  expect(firstText).toContain('You are powered by the model old-test-model.')
+  expect(secondText).toContain('You are powered by the model new-test-model.')
+  expect(secondText).not.toContain('You are powered by the model old-test-model.')
+})
+
 test('built-in agent prompts describe OpenClaude instead of Claude Code', () => {
   expect(DEFAULT_AGENT_PROMPT).toContain('OpenClaude')
   expect(DEFAULT_AGENT_PROMPT).not.toContain('Claude Code')
diff --git a/src/constants/prompts.ts b/src/constants/prompts.ts
index 52054df7..53691ab1 100644
--- a/src/constants/prompts.ts
+++ b/src/constants/prompts.ts
@@ -496,7 +496,7 @@ ${CYBER_RISK_INSTRUCTION}`,
     systemPromptSection('ant_model_override', () =>
       getAntModelOverrideSection(),
     ),
-    systemPromptSection('env_info_simple', () =>
+    systemPromptSection(`env_info_simple:${model}`, () =>
       computeSimpleEnvInfo(model, additionalWorkingDirectories),
     ),
     systemPromptSection('language', () =>
@@ -519,7 +519,7 @@ ${CYBER_RISK_INSTRUCTION}`,
       'MCP servers connect/disconnect between turns',
     ),
     systemPromptSection('scratchpad', () => getScratchpadInstructions()),
-    systemPromptSection('frc', () => getFunctionResultClearingSection(model)),
+    systemPromptSection(`frc:${model}`, () => getFunctionResultClearingSection(model)),
     systemPromptSection(
       'summarize_tool_results',
       () => SUMMARIZE_TOOL_RESULTS_SECTION,
diff --git a/src/query.ts b/src/query.ts
index 6187ed61..fe2e84e6 100644
--- a/src/query.ts
+++ b/src/query.ts
@@ -77,6 +77,7 @@ import {
 import { notifyCommandLifecycle } from './utils/commandLifecycle.js'
 import { headlessProfilerCheckpoint } from './utils/headlessProfiler.js'
 import {
+  getDefaultMainLoopModelSetting,
   getRuntimeMainLoopModel,
   renderModelName,
 } from './utils/model/model.js'
@@ -604,9 +605,13 @@ async function* queryLoop(
 
     const appState = toolUseContext.getAppState()
     const permissionMode = appState.toolPermissionContext.mode
+    const appStateMainLoopModel =
+      appState.mainLoopModelForSession ??
+      appState.mainLoopModel ??
+      getDefaultMainLoopModelSetting()
     let currentModel = getRuntimeMainLoopModel({
       permissionMode,
-      mainLoopModel: toolUseContext.options.mainLoopModel,
+      mainLoopModel: appStateMainLoopModel,
       exceeds200kTokens:
         permissionMode === 'plan' &&
         doesMostRecentAssistantMessageExceed200k(messagesForQuery),
diff --git a/src/utils/auth.ts b/src/utils/auth.ts
index b4a67f24..69774d93 100644
--- a/src/utils/auth.ts
+++ b/src/utils/auth.ts
@@ -130,10 +130,18 @@ export function isAnthropicAuthEnabled(): boolean {
     apiKeyHelper ||
     process.env.CLAUDE_CODE_API_KEY_FILE_DESCRIPTOR
 
-  // Check if API key is from an external source (not managed by /login)
-  const { source: apiKeySource } = getAnthropicApiKeyWithSource({
-    skipRetrievingKeyFromApiKeyHelper: true,
-  })
+  // Check if API key is from an external source (not managed by /login).
+  // Predicate must not throw: getAnthropicApiKeyWithSource throws under
+  // CI/NODE_ENV=test when no key is configured, but here we just want to
+  // know the source — "no key" is a valid answer.
+  let apiKeySource: ApiKeySource
+  try {
+    ;({ source: apiKeySource } = getAnthropicApiKeyWithSource({
+      skipRetrievingKeyFromApiKeyHelper: true,
+    }))
+  } catch {
+    apiKeySource = 'none'
+  }
   const hasExternalApiKey =
     apiKeySource === 'ANTHROPIC_API_KEY' || apiKeySource === 'apiKeyHelper'
 
@@ -221,10 +229,17 @@ export function getAnthropicApiKey(): null | string {
 }
 
 export function hasAnthropicApiKeyAuth(): boolean {
-  const { key, source } = getAnthropicApiKeyWithSource({
-    skipRetrievingKeyFromApiKeyHelper: true,
-  })
-  return key !== null && source !== 'none'
+  // Predicate: never throw. getAnthropicApiKeyWithSource throws under
+  // CI/NODE_ENV=test when no key is configured — but "do we have auth?" is
+  // exactly the question that has to answer cleanly in that state.
+  try {
+    const { key, source } = getAnthropicApiKeyWithSource({
+      skipRetrievingKeyFromApiKeyHelper: true,
+    })
+    return key !== null && source !== 'none'
+  } catch {
+    return false
+  }
 }
 
 export function getAnthropicApiKeyWithSource(