fix: Route Claude attribution by model name

Provider-managed environments should preserve Claude attribution only when the selected model is actually Claude-prefixed. Non-Claude provider models now disable the attribution header so third-party providers do not inherit Claude-specific prompt metadata.

Constraint: Claude model detection is intentionally model-name based to match the requested provider policy.
Rejected: Remove attribution headers globally | official Claude-prefixed models should keep existing behavior.
Confidence: high
Scope-risk: moderate
Directive: Do not broaden this policy without live provider request-shape verification.
Tested: Targeted server, provider, settings, cron, and managed-env tests in prior verification pass.
Not-tested: Full verify gate after this commit.

src/server/__tests__/conversation-service.test.ts

@@ -17,6 +17,7 @@ describe('ConversationService', () => {
   let originalOAuthToken: string | undefined
   let originalProviderManagedByHost: string | undefined
   let originalDiagnosticsFile: string | undefined
+  let originalAttributionHeader: string | undefined
   let originalHome: string | undefined
   let originalPath: string | undefined
   let originalShell: string | undefined
@@ -34,6 +35,7 @@ describe('ConversationService', () => {
     originalOAuthToken = process.env.CLAUDE_CODE_OAUTH_TOKEN
     originalProviderManagedByHost = process.env.CLAUDE_CODE_PROVIDER_MANAGED_BY_HOST
     originalDiagnosticsFile = process.env.CLAUDE_CODE_DIAGNOSTICS_FILE
+    originalAttributionHeader = process.env.CLAUDE_CODE_ATTRIBUTION_HEADER
     originalHome = process.env.HOME
     originalPath = process.env.PATH
     originalShell = process.env.SHELL
@@ -51,6 +53,7 @@ describe('ConversationService', () => {
     delete process.env.CLAUDE_CODE_ENTRYPOINT
     delete process.env.CLAUDE_CODE_PROVIDER_MANAGED_BY_HOST
     delete process.env.CLAUDE_CODE_DIAGNOSTICS_FILE
+    delete process.env.CLAUDE_CODE_ATTRIBUTION_HEADER
     process.env.CC_HAHA_DISABLE_TERMINAL_SHELL_ENV = '1'
     resetTerminalShellEnvironmentCacheForTests()
   })
@@ -83,6 +86,9 @@ describe('ConversationService', () => {
     if (originalDiagnosticsFile === undefined) delete process.env.CLAUDE_CODE_DIAGNOSTICS_FILE
     else process.env.CLAUDE_CODE_DIAGNOSTICS_FILE = originalDiagnosticsFile
 
+    if (originalAttributionHeader === undefined) delete process.env.CLAUDE_CODE_ATTRIBUTION_HEADER
+    else process.env.CLAUDE_CODE_ATTRIBUTION_HEADER = originalAttributionHeader
+
     if (originalHome === undefined) delete process.env.HOME
     else process.env.HOME = originalHome
 
@@ -133,6 +139,7 @@ describe('ConversationService', () => {
     expect(env.ANTHROPIC_AUTH_TOKEN).toBe('test-token')
     expect(env.ANTHROPIC_BASE_URL).toBe('https://example.invalid/anthropic')
     expect(env.ANTHROPIC_MODEL).toBe('test-model')
+    expect(env.CLAUDE_CODE_ATTRIBUTION_HEADER).toBe('0')
     expect(env.CLAUDE_CODE_DIAGNOSTICS_FILE).toBe(path.join(tmpDir, 'cc-haha', 'diagnostics', 'cli-diagnostics.jsonl'))
     expect(env.CLAUDE_COWORK_MEMORY_PATH_OVERRIDE).toBe(
       `${path.join(tmpDir, 'projects', 'D--workspace-code-myself-code-cc-haha', 'memory')}${path.sep}`,
@@ -280,6 +287,7 @@ describe('ConversationService', () => {
     expect(env.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('kimi-k2.6')
     expect(env.ANTHROPIC_DEFAULT_OPUS_MODEL).toBe('kimi-k2.6')
     expect(env.CLAUDE_CODE_PROVIDER_MANAGED_BY_HOST).toBe('1')
+    expect(env.CLAUDE_CODE_ATTRIBUTION_HEADER).toBe('0')
     expect(env.CLAUDE_CODE_ENTRYPOINT).toBeUndefined()
   })
 
@@ -307,6 +315,7 @@ describe('ConversationService', () => {
 
     expect(env.ANTHROPIC_BASE_URL).toBe(`http://127.0.0.1:3456/proxy/providers/${provider.id}`)
     expect(env.ANTHROPIC_MODEL).toBe('new-provider-sonnet')
+    expect(env.CLAUDE_CODE_ATTRIBUTION_HEADER).toBe('0')
   })
 
   test('buildChildEnv clears stale api key for bearer-token providers', async () => {
@@ -336,6 +345,7 @@ describe('ConversationService', () => {
     expect(env.ANTHROPIC_API_KEY).toBe('')
     expect(env.ANTHROPIC_MODEL).toBe('claude-sonnet-4-6')
     expect(env.ANTHROPIC_DEFAULT_SONNET_MODEL_SUPPORTED_CAPABILITIES).toBe('none')
+    expect(env.CLAUDE_CODE_ATTRIBUTION_HEADER).toBe('1')
   })
 
   test('buildChildEnv can force official auth even when a custom default provider exists', async () => {

src/server/__tests__/cron-scheduler-launcher.test.ts

@@ -326,6 +326,7 @@ describe('cron scheduler launcher resolution', () => {
     expect(env.ANTHROPIC_MODEL).toBe('provider-fast')
     expect(env.ANTHROPIC_MODEL).not.toBe('stale-parent-model')
     expect(env.CLAUDE_CODE_PROVIDER_MANAGED_BY_HOST).toBe('1')
+    expect(env.CLAUDE_CODE_ATTRIBUTION_HEADER).toBe('0')
     expect(env.CLAUDE_CODE_ENTRYPOINT).toBe('sdk-cli')
   })
 

src/server/__tests__/providers.test.ts

@@ -523,9 +523,31 @@ describe('ProviderService', () => {
       expect(env.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('model-haiku')
       expect(env.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('model-sonnet')
       expect(env.ANTHROPIC_DEFAULT_OPUS_MODEL).toBe('model-opus')
+      expect(env.CLAUDE_CODE_ATTRIBUTION_HEADER).toBe('0')
       expect(env.CLAUDE_CODE_AUTO_COMPACT_WINDOW).toBeUndefined()
     })
 
+    test('should preserve attribution header for Claude-prefixed provider models', async () => {
+      const svc = new ProviderService()
+      const provider = await svc.addProvider(sampleInput({
+        models: {
+          main: 'Claude Sonnet 4.6',
+          haiku: 'Claude Haiku 4.5',
+          sonnet: 'Claude Sonnet 4.6',
+          opus: 'Claude Opus 4.7',
+        },
+      }))
+
+      await svc.activateProvider(provider.id)
+
+      const settings = await readSettings()
+      const env = settings.env as Record<string, string>
+      expect(env.CLAUDE_CODE_ATTRIBUTION_HEADER).toBe('1')
+
+      const runtimeEnv = await svc.getProviderRuntimeEnv(provider.id)
+      expect(runtimeEnv.CLAUDE_CODE_ATTRIBUTION_HEADER).toBe('1')
+    })
+
     test('should honor provider auth env strategies on activation and runtime env', async () => {
       const svc = new ProviderService()
 
@@ -615,6 +637,7 @@ describe('ProviderService', () => {
       expect(clearedEnv.API_TIMEOUT_MS).toBeUndefined()
       expect(clearedEnv.CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC).toBeUndefined()
       expect(clearedEnv.CLAUDE_CODE_AUTO_COMPACT_WINDOW).toBeUndefined()
+      expect(clearedEnv.CLAUDE_CODE_ATTRIBUTION_HEADER).toBeUndefined()
       expect(clearedEnv.CLAUDE_CODE_MODEL_CONTEXT_WINDOWS).toBeUndefined()
     })
 

src/server/__tests__/settings.test.ts

@@ -620,6 +620,7 @@ describe('Models API', () => {
 
     const managedSettings = await providerSvc.getManagedSettings()
     expect(managedSettings.model).toBe('glm-5-turbo')
+    expect((managedSettings.env as Record<string, string>).CLAUDE_CODE_ATTRIBUTION_HEADER).toBe('0')
 
     const globalSettings = await settingsSvc.getUserSettings()
     expect(globalSettings.model).toBeUndefined()

src/server/api/models.ts

@@ -10,6 +10,7 @@
 
 import { SettingsService } from '../services/settingsService.js'
 import { ProviderService } from '../services/providerService.js'
+import { attributionHeaderEnvForModel } from '../services/attributionHeaderPolicy.js'
 import { ApiError, errorResponse } from '../middleware/errorHandler.js'
 import { hasOpenAIAuthLogin } from '../../utils/auth.js'
 import { OPENAI_CODEX_MODEL_CATALOG } from '../../services/openaiAuth/models.js'
@@ -275,7 +276,16 @@ async function handleCurrentModel(req: Request): Promise<Response> {
     }
     const { activeId } = await providerService.listProviders()
     if (activeId) {
-      await providerService.updateManagedSettings(updates)
+      const currentManagedSettings = await providerService.getManagedSettings()
+      const currentEnv =
+        (currentManagedSettings.env as Record<string, string> | undefined) ?? {}
+      await providerService.updateManagedSettings({
+        ...updates,
+        env: {
+          ...currentEnv,
+          ...attributionHeaderEnvForModel(baseId),
+        },
+      })
     } else {
       await settingsService.updateUserSettings(updates)
     }

src/server/services/attributionHeaderPolicy.ts

@@ -0,0 +1,16 @@
+export const ATTRIBUTION_HEADER_ENV_KEY = 'CLAUDE_CODE_ATTRIBUTION_HEADER'
+
+export function isClaudeModelName(modelName?: string | null): boolean {
+  return typeof modelName === 'string' && modelName.trim().toLowerCase().startsWith('claude')
+}
+
+export function attributionHeaderEnvForModel(
+  modelName?: string | null,
+): Record<string, string> {
+  const normalizedModel = modelName?.trim()
+  if (!normalizedModel) return {}
+
+  return {
+    [ATTRIBUTION_HEADER_ENV_KEY]: isClaudeModelName(normalizedModel) ? '1' : '0',
+  }
+}

src/server/services/conversationService.ts

@@ -26,6 +26,7 @@ import { getClaudeConfigHomeDir } from '../../utils/envUtils.js'
 import { findCanonicalGitRoot } from '../../utils/git.js'
 import { sanitizePath } from '../../utils/path.js'
 import { getProcessEnvWithTerminalShellEnvironment } from '../../utils/terminalShellEnvironment.js'
+import { attributionHeaderEnvForModel } from './attributionHeaderPolicy.js'
 
 const MAX_CAPTURED_PROCESS_LINES = 80
 const MAX_CAPTURED_SDK_MESSAGES = 40
@@ -885,6 +886,7 @@ export class ConversationService {
       'ANTHROPIC_DEFAULT_OPUS_MODEL_SUPPORTED_CAPABILITIES',
       'CC_HAHA_SEND_DISABLED_THINKING',
       'CLAUDE_CODE_AUTO_COMPACT_WINDOW',
+      'CLAUDE_CODE_ATTRIBUTION_HEADER',
       'CLAUDE_CODE_MODEL_CONTEXT_WINDOWS',
     ] as const
 
@@ -913,6 +915,11 @@ export class ConversationService {
     if (explicitProviderEnv && options?.model?.trim()) {
       explicitProviderEnv.ANTHROPIC_MODEL = options.model.trim()
     }
+    const attributionHeaderEnv = attributionHeaderEnvForModel(
+      options?.model?.trim() ||
+        explicitProviderEnv?.ANTHROPIC_MODEL ||
+        cleanEnv.ANTHROPIC_MODEL,
+    )
 
     const cliDiagnosticsPath = diagnosticsService.getCliDiagnosticsPath()
     try {
@@ -957,6 +964,7 @@ export class ConversationService {
       ...(this.shouldMarkManagedOAuth(options?.providerId)
         ? await this.buildOfficialOAuthEnv()
         : {}),
+      ...attributionHeaderEnv,
     }
   }
 
@@ -1034,6 +1042,7 @@ export class ConversationService {
         'ANTHROPIC_DEFAULT_OPUS_MODEL_SUPPORTED_CAPABILITIES',
         'CC_HAHA_SEND_DISABLED_THINKING',
         'CLAUDE_CODE_AUTO_COMPACT_WINDOW',
+        'CLAUDE_CODE_ATTRIBUTION_HEADER',
         'CLAUDE_CODE_MODEL_CONTEXT_WINDOWS',
       ].some((key) => typeof env[key] === 'string' && env[key]!.trim().length > 0)
     } catch {

src/server/services/cronScheduler.ts

@@ -22,6 +22,7 @@ import {
   resolveClaudeCliLauncher,
 } from '../../utils/desktopBundledCli.js'
 import { getProcessEnvWithTerminalShellEnvironment } from '../../utils/terminalShellEnvironment.js'
+import { attributionHeaderEnvForModel } from './attributionHeaderPolicy.js'
 
 // ─── Types ─────────────────────────────────────────────────────────────────────
 
@@ -659,6 +660,11 @@ export class CronScheduler {
     if (explicitProviderEnv && task.model?.trim()) {
       explicitProviderEnv.ANTHROPIC_MODEL = task.model.trim()
     }
+    const attributionHeaderEnv = attributionHeaderEnvForModel(
+      task.model?.trim() ||
+        explicitProviderEnv?.ANTHROPIC_MODEL ||
+        cleanEnv.ANTHROPIC_MODEL,
+    )
 
     return {
       ...cleanEnv,
@@ -677,6 +683,7 @@ export class CronScheduler {
       ...(this.shouldMarkManagedOAuth(task.providerId)
         ? await this.buildOfficialOAuthEnv()
         : {}),
+      ...attributionHeaderEnv,
     }
   }
 

src/server/services/providerService.ts

@@ -19,6 +19,10 @@ import { openaiResponsesToAnthropic } from '../proxy/transform/openaiResponsesTo
 import type { AnthropicRequest, AnthropicResponse } from '../proxy/transform/types.js'
 import { PROVIDER_PRESETS } from '../config/providerPresets.js'
 import { MODEL_CONTEXT_WINDOWS_ENV_KEY } from '../../utils/model/modelContextWindows.js'
+import {
+  ATTRIBUTION_HEADER_ENV_KEY,
+  attributionHeaderEnvForModel,
+} from './attributionHeaderPolicy.js'
 import {
   CURRENT_PROVIDER_INDEX_SCHEMA_VERSION,
   ensurePersistentStorageUpgraded,
@@ -47,6 +51,7 @@ const MANAGED_ENV_KEYS = [
   'ANTHROPIC_DEFAULT_OPUS_MODEL',
   'ANTHROPIC_DEFAULT_OPUS_MODEL_SUPPORTED_CAPABILITIES',
   'CLAUDE_CODE_AUTO_COMPACT_WINDOW',
+  ATTRIBUTION_HEADER_ENV_KEY,
   MODEL_CONTEXT_WINDOWS_ENV_KEY,
 ] as const
 
@@ -393,6 +398,7 @@ export class ProviderService {
       ANTHROPIC_DEFAULT_HAIKU_MODEL: provider.models.haiku,
       ANTHROPIC_DEFAULT_SONNET_MODEL: provider.models.sonnet,
       ANTHROPIC_DEFAULT_OPUS_MODEL: provider.models.opus,
+      ...attributionHeaderEnvForModel(provider.models.main),
     }
   }
 

src/utils/__tests__/providerManagedEnvCompat.test.ts

@@ -1,4 +1,5 @@
 import { describe, expect, test } from 'bun:test'
+import { isProviderManagedEnvVar } from '../managedEnvConstants.js'
 import { normalizeLegacyDeepSeekManagedEnv } from '../providerManagedEnvCompat.js'
 
 describe('provider managed env compatibility', () => {
@@ -36,4 +37,8 @@ describe('provider managed env compatibility', () => {
     expect(changed).toBe(false)
     expect(env).toBe(input)
   })
+
+  test('treats attribution header routing as provider-managed env', () => {
+    expect(isProviderManagedEnvVar('CLAUDE_CODE_ATTRIBUTION_HEADER')).toBe(true)
+  })
 })

src/utils/managedEnvConstants.ts

@@ -59,6 +59,7 @@ const PROVIDER_MANAGED_ENV_VARS = new Set([
   'ANTHROPIC_SMALL_FAST_MODEL_AWS_REGION',
   'CLAUDE_CODE_SUBAGENT_MODEL',
   'CLAUDE_CODE_AUTO_COMPACT_WINDOW',
+  'CLAUDE_CODE_ATTRIBUTION_HEADER',
   'CLAUDE_CODE_MODEL_CONTEXT_WINDOWS',
 ])