fix(config): fix duplicate model in /model picker for haiku/opus-only tenants (EPMCDME-12779)

src/agents/core/BaseAgentAdapter.ts

@@ -1062,15 +1062,27 @@ export abstract class BaseAgentAdapter implements AgentAdapter {
     }
 
     // Transform model tiers (haiku/sonnet/opus)
+    // Note: All tier vars were already cleared in Step 1 above
     if (env.CODEMIE_HAIKU_MODEL && envMapping.haikuModel) {
       for (const envVar of envMapping.haikuModel) {
         env[envVar] = env.CODEMIE_HAIKU_MODEL;
       }
     }
-    if (env.CODEMIE_SONNET_MODEL && envMapping.sonnetModel) {
+    if (env.CODEMIE_SONNET_MODEL && env.CODEMIE_SONNET_MODEL !== env.CODEMIE_HAIKU_MODEL && envMapping.sonnetModel) {
+      // Distinct sonnet tier — map to all target vars normally
       for (const envVar of envMapping.sonnetModel) {
         env[envVar] = env.CODEMIE_SONNET_MODEL;
       }
+    } else if ((!env.CODEMIE_SONNET_MODEL || env.CODEMIE_SONNET_MODEL === env.CODEMIE_HAIKU_MODEL) && env.CODEMIE_OPUS_MODEL && envMapping.sonnetModel?.includes('CLAUDE_CODE_SUBAGENT_MODEL')) {
+      // No distinct sonnet tier, opus provisioned: route subagent to opus.
+      // ANTHROPIC_DEFAULT_SONNET_MODEL is intentionally left unset to prevent
+      // duplicate-ID display in /model (EPMCDME-12779).
+      env['CLAUDE_CODE_SUBAGENT_MODEL'] = env.CODEMIE_OPUS_MODEL;
+    } else if ((!env.CODEMIE_SONNET_MODEL || env.CODEMIE_SONNET_MODEL === env.CODEMIE_HAIKU_MODEL) && !env.CODEMIE_OPUS_MODEL && env.CODEMIE_HAIKU_MODEL && envMapping.sonnetModel?.includes('CLAUDE_CODE_SUBAGENT_MODEL')) {
+      // Haiku-only tenant: route subagent to haiku.
+      // ANTHROPIC_DEFAULT_SONNET_MODEL is intentionally left unset to prevent
+      // duplicate-ID display in /model (EPMCDME-12779).
+      env['CLAUDE_CODE_SUBAGENT_MODEL'] = env.CODEMIE_HAIKU_MODEL;
     }
     if (env.CODEMIE_OPUS_MODEL && envMapping.opusModel) {
       for (const envVar of envMapping.opusModel) {

src/agents/core/__tests__/model-tier-config.test.ts

@@ -64,9 +64,10 @@ describe('Model Tier Configuration', () => {
     vi.restoreAllMocks();
   });
 
-  it('should transform CODEMIE_HAIKU_MODEL to ANTHROPIC_DEFAULT_HAIKU_MODEL', () => {
+  it('should transform CODEMIE_HAIKU_MODEL to ANTHROPIC_DEFAULT_HAIKU_MODEL when sonnet is also present', () => {
     const env: NodeJS.ProcessEnv = {
       CODEMIE_HAIKU_MODEL: 'claude-haiku-4-5-20251001',
+      CODEMIE_SONNET_MODEL: 'claude-sonnet-4-6', // not haiku-only → normal mapping applies
     };
 
     const result = adapter.testTransformEnvVars(env);
@@ -161,17 +162,39 @@ describe('Model Tier Configuration', () => {
     expect(result.ANTHROPIC_DEFAULT_OPUS_MODEL).toBeUndefined();
   });
 
-  it('should handle partial tier configuration', () => {
+  it('should handle haiku-only configuration by mapping haiku to its slot and CLAUDE_CODE_SUBAGENT_MODEL (EPMCDME-12779)', () => {
     const env: NodeJS.ProcessEnv = {
       CODEMIE_HAIKU_MODEL: 'claude-haiku-4-5-20251001',
       // sonnetModel and opusModel not provided
     };
 
     const result = adapter.testTransformEnvVars(env);
 
-    // Only haiku should be set
+    // Haiku-only: set ANTHROPIC_DEFAULT_HAIKU_MODEL normally; ANTHROPIC_DEFAULT_SONNET_MODEL
+    // is intentionally left unset. CLAUDE_CODE_SUBAGENT_MODEL routes background tasks to haiku.
     expect(result.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('claude-haiku-4-5-20251001');
     expect(result.ANTHROPIC_DEFAULT_SONNET_MODEL).toBeUndefined();
+    expect(result.CLAUDE_CODE_SUBAGENT_MODEL).toBe('claude-haiku-4-5-20251001');
+    expect(result.ANTHROPIC_DEFAULT_OPUS_MODEL).toBeUndefined();
+  });
+
+  it('should clear stale sonnet/opus vars when switching to haiku-only config (EPMCDME-12779)', () => {
+    // Simulates the user removing sonnet/opus from config after a prior session that had
+    // all three tiers — stale ANTHROPIC_DEFAULT_SONNET_MODEL and ANTHROPIC_DEFAULT_OPUS_MODEL
+    // must not survive.
+    const env: NodeJS.ProcessEnv = {
+      ANTHROPIC_DEFAULT_HAIKU_MODEL: 'claude-haiku-4-5-20251001',
+      ANTHROPIC_DEFAULT_SONNET_MODEL: 'claude-sonnet-4-6',
+      ANTHROPIC_DEFAULT_OPUS_MODEL: 'claude-opus-4-6-20260205',
+      CODEMIE_HAIKU_MODEL: 'claude-haiku-4-5-20251001',
+      // CODEMIE_SONNET_MODEL and CODEMIE_OPUS_MODEL absent — haiku-only
+    };
+
+    const result = adapter.testTransformEnvVars(env);
+
+    expect(result.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('claude-haiku-4-5-20251001');
+    expect(result.ANTHROPIC_DEFAULT_SONNET_MODEL).toBeUndefined();
+    expect(result.CLAUDE_CODE_SUBAGENT_MODEL).toBe('claude-haiku-4-5-20251001');
     expect(result.ANTHROPIC_DEFAULT_OPUS_MODEL).toBeUndefined();
   });
 
@@ -236,9 +259,10 @@ describe('ConfigLoader.exportProviderEnvVars', () => {
     const env = ConfigLoader.exportProviderEnvVars(config);
 
     expect(env.CODEMIE_MODEL).toBe('claude-4-5-sonnet');
-    expect(env.CODEMIE_HAIKU_MODEL).toBeUndefined();
-    expect(env.CODEMIE_SONNET_MODEL).toBeUndefined();
-    expect(env.CODEMIE_OPUS_MODEL).toBeUndefined();
+    // Always emitted as empty string to override stale shell values (EPMCDME-12779)
+    expect(env.CODEMIE_HAIKU_MODEL).toBe('');
+    expect(env.CODEMIE_SONNET_MODEL).toBe('');
+    expect(env.CODEMIE_OPUS_MODEL).toBe('');
   });
 
   it('should not export placeholder auth token for anthropic-subscription', async () => {

src/cli/commands/__tests__/model-tier-auto-selection.test.ts

@@ -9,7 +9,8 @@
  * - Environment variable priority
  */
 
-import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { autoSelectModelTiers } from '../setup.js';
 
 // Import the functions we want to test
 // We'll need to export them from setup.ts for testing
@@ -382,3 +383,67 @@ describe('autoSelectModelTiers integration', () => {
     });
   });
 });
+
+describe('autoSelectModelTiers — opus-only tenant (EPMCDME-12779)', () => {
+  beforeEach(() => {
+    vi.stubEnv('ANTHROPIC_DEFAULT_HAIKU_MODEL', '');
+    vi.stubEnv('ANTHROPIC_DEFAULT_SONNET_MODEL', '');
+    vi.stubEnv('ANTHROPIC_DEFAULT_OPUS_MODEL', '');
+  });
+
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
+  it('should not set sonnetModel when selectedModel is opus-class', async () => {
+    const models = ['claude-opus-4-6-20260205'];
+    const result = await autoSelectModelTiers(models, 'claude-opus-4-6-20260205');
+    expect(result.sonnetModel).toBeUndefined();
+    expect(result.opusModel).toBe('claude-opus-4-6-20260205');
+  });
+
+  it('should not set sonnetModel when selectedModel contains opus keyword', async () => {
+    const models = ['claude-opus-4-7', 'claude-haiku-4-5-20251001'];
+    const result = await autoSelectModelTiers(models, 'claude-opus-4-7');
+    expect(result.sonnetModel).toBeUndefined();
+    expect(result.opusModel).toBe('claude-opus-4-7');
+    expect(result.haikuModel).toBe('claude-haiku-4-5-20251001');
+  });
+
+  it('should set sonnetModel normally when selectedModel is sonnet-class', async () => {
+    const models = ['claude-sonnet-4-6', 'claude-opus-4-6-20260205', 'claude-haiku-4-5-20251001'];
+    const result = await autoSelectModelTiers(models, 'claude-sonnet-4-6');
+    expect(result.sonnetModel).toBe('claude-sonnet-4-6');
+    expect(result.opusModel).toBe('claude-opus-4-6-20260205');
+    expect(result.haikuModel).toBe('claude-haiku-4-5-20251001');
+  });
+
+  it('should not set sonnetModel when selectedModel is a custom/unknown model ID', async () => {
+    const models = ['my-enterprise-llm', 'claude-haiku-4-5-20251001'];
+    const result = await autoSelectModelTiers(models, 'my-enterprise-llm');
+    expect(result.sonnetModel).toBeUndefined();
+    expect(result.haikuModel).toBe('claude-haiku-4-5-20251001');
+  });
+
+  it('should auto-select sonnet from models list when selectedModel is haiku-class (EPMCDME-12779)', async () => {
+    // User selects haiku as primary but tenant also has sonnet provisioned.
+    // sonnetModel must be assigned from the list so Claude Code's Custom Sonnet slot
+    // shows the real sonnet model instead of falling back to the selected haiku model.
+    const models = ['claude-haiku-4-5-20251001', 'claude-sonnet-4-6', 'claude-opus-4-6-20260205'];
+    const result = await autoSelectModelTiers(models, 'claude-haiku-4-5-20251001');
+    expect(result.sonnetModel).toBe('claude-sonnet-4-6');
+    expect(result.haikuModel).toBe('claude-haiku-4-5-20251001');
+    expect(result.opusModel).toBe('claude-opus-4-6-20260205');
+  });
+
+  it('should not set sonnetModel when no sonnet model is in the available list', async () => {
+    // True no-sonnet tenant: only haiku and opus provisioned.
+    // sonnetModel must remain undefined so the haiku-only/opus-only fallback in
+    // BaseAgentAdapter can handle the slot routing correctly.
+    const models = ['claude-haiku-4-5-20251001', 'claude-opus-4-6-20260205'];
+    const result = await autoSelectModelTiers(models, 'claude-haiku-4-5-20251001');
+    expect(result.sonnetModel).toBeUndefined();
+    expect(result.haikuModel).toBe('claude-haiku-4-5-20251001');
+    expect(result.opusModel).toBe('claude-opus-4-6-20260205');
+  });
+});

src/cli/commands/setup.ts

@@ -296,9 +296,9 @@ async function handlePluginSetup(
     }
 
     // Merge model tiers into config
-    if (modelTiers.haikuModel) config.haikuModel = modelTiers.haikuModel;
-    if (modelTiers.sonnetModel) config.sonnetModel = modelTiers.sonnetModel;
-    if (modelTiers.opusModel) config.opusModel = modelTiers.opusModel;
+    config.haikuModel = modelTiers.haikuModel;
+    config.sonnetModel = modelTiers.sonnetModel;
+    config.opusModel = modelTiers.opusModel;
 
     // Step 5: Ask for profile name (if creating new)
     let finalProfileName = profileName;
@@ -574,7 +574,7 @@ function compareModelVersions(a: string, b: string): number {
  *
  * Latest = highest version number parsed from model name
  */
-async function autoSelectModelTiers(
+export async function autoSelectModelTiers(
   models: string[],
   selectedModel: string
 ): Promise<{ haikuModel?: string; sonnetModel?: string; opusModel?: string }> {
@@ -583,29 +583,16 @@ async function autoSelectModelTiers(
   const envSonnet = process.env.ANTHROPIC_DEFAULT_SONNET_MODEL;
   const envOpus = process.env.ANTHROPIC_DEFAULT_OPUS_MODEL;
 
-  // If all env vars are set, use those
-  if (envHaiku && envSonnet && envOpus) {
-    logger.debug('Using model tiers from environment variables', {
-      haiku: envHaiku,
-      sonnet: envSonnet,
-      opus: envOpus
-    });
-    return {
-      haikuModel: envHaiku,
-      sonnetModel: envSonnet,
-      opusModel: envOpus
-    };
-  }
-
-  // Otherwise, auto-select from available models
+  // Auto-select from available models with validation against env vars
   const result: { haikuModel?: string; sonnetModel?: string; opusModel?: string } = {};
 
   // Filter models by type
   const haikuModels = models.filter(m => m.toLowerCase().includes('haiku'));
+  const sonnetModels = models.filter(m => m.toLowerCase().includes('sonnet'));
   const opusModels = models.filter(m => m.toLowerCase().includes('opus'));
 
-  // Select latest haiku model (or use env var if set)
-  if (envHaiku) {
+  // Select latest haiku model (or use env var if set and valid)
+  if (envHaiku && haikuModels.includes(envHaiku)) {
     result.haikuModel = envHaiku;
     logger.debug('Using haiku model from environment variable', { model: envHaiku });
   } else if (haikuModels.length > 0) {
@@ -621,17 +608,32 @@ async function autoSelectModelTiers(
     });
   }
 
-  // Use selected model as sonnet tier (or env var if set)
-  if (envSonnet) {
+  // Select sonnet model: prefer env var (if valid), then selectedModel if it's sonnet-class, then
+  // auto-select the latest sonnet model from the available list (same pattern as haiku/opus).
+  // This ensures the Custom Sonnet slot in Claude Code's /model picker is always populated
+  // with a real sonnet model when one is provisioned, regardless of which tier the user
+  // selected as their primary model (EPMCDME-12779).
+  if (envSonnet && sonnetModels.includes(envSonnet)) {
     result.sonnetModel = envSonnet;
     logger.debug('Using sonnet model from environment variable', { model: envSonnet });
-  } else {
+  } else if (selectedModel.toLowerCase().includes('sonnet')) {
     result.sonnetModel = selectedModel;
     logger.debug('Using selected model as sonnet tier', { model: selectedModel });
+  } else if (sonnetModels.length > 0) {
+    const sortedSonnet = [...sonnetModels].sort((a, b) => compareModelVersions(b, a));
+    const latestSonnet = sortedSonnet[0];
+    result.sonnetModel = latestSonnet;
+    logger.debug('Auto-selected sonnet model', {
+      selected: latestSonnet,
+      candidates: sonnetModels,
+      sortedOrder: sortedSonnet
+    });
+  } else {
+    logger.debug('No sonnet model available — sonnet tier not assigned', { availableModels: models });
   }
 
-  // Select latest opus model (or use env var if set)
-  if (envOpus) {
+  // Select latest opus model (or use env var if set and valid)
+  if (envOpus && opusModels.includes(envOpus)) {
     result.opusModel = envOpus;
     logger.debug('Using opus model from environment variable', { model: envOpus });
   } else if (opusModels.length > 0) {

src/providers/plugins/bedrock/bedrock.template.ts

@@ -109,13 +109,30 @@ export const BedrockTemplate = registerProvider<ProviderTemplate>({
         }
 
         // Model tier configuration for Bedrock
-        // Maps CodeMie tier models to Claude Code environment variables
+        // Maps CodeMie tier models to Claude Code environment variables.
+        // Clear stale values first so haiku-only / opus-only tenants don't inherit
+        // vars from a prior process and show duplicates in /model (EPMCDME-12779).
+        delete env.ANTHROPIC_DEFAULT_HAIKU_MODEL;
+        delete env.ANTHROPIC_DEFAULT_SONNET_MODEL;
+        delete env.ANTHROPIC_DEFAULT_OPUS_MODEL;
+        delete env.CLAUDE_CODE_SUBAGENT_MODEL;
         if (env.CODEMIE_HAIKU_MODEL) {
           env.ANTHROPIC_DEFAULT_HAIKU_MODEL = env.CODEMIE_HAIKU_MODEL;
         }
-        if (env.CODEMIE_SONNET_MODEL) {
+        if (env.CODEMIE_SONNET_MODEL && env.CODEMIE_SONNET_MODEL !== env.CODEMIE_HAIKU_MODEL) {
           env.ANTHROPIC_DEFAULT_SONNET_MODEL = env.CODEMIE_SONNET_MODEL;
           env.CLAUDE_CODE_SUBAGENT_MODEL = env.CODEMIE_SONNET_MODEL;
+        } else if (env.CODEMIE_OPUS_MODEL) {
+          // Opus-only tenant: route subagent to opus; ANTHROPIC_DEFAULT_SONNET_MODEL is
+          // intentionally left unset to prevent duplicate-ID display (EPMCDME-12779 FR-002).
+          env.CLAUDE_CODE_SUBAGENT_MODEL = env.CODEMIE_OPUS_MODEL;
+        } else if (env.CODEMIE_HAIKU_MODEL) {
+          // Haiku-only tenant: set CLAUDE_CODE_SUBAGENT_MODEL so background tasks use the
+          // provisioned model. ANTHROPIC_DEFAULT_SONNET_MODEL is intentionally left unset.
+          // Routing haiku through the sonnet slot caused a duplicate because Claude Code
+          // shows its built-in haiku default even when ANTHROPIC_DEFAULT_HAIKU_MODEL is not
+          // set (EPMCDME-12779).
+          env.CLAUDE_CODE_SUBAGENT_MODEL = env.CODEMIE_HAIKU_MODEL;
         }
         if (env.CODEMIE_OPUS_MODEL) {
           env.ANTHROPIC_DEFAULT_OPUS_MODEL = env.CODEMIE_OPUS_MODEL;

src/utils/config.ts

@@ -1387,9 +1387,12 @@ export class ConfigLoader {
 
     if (config.model) env.CODEMIE_MODEL = config.model;
     if (config.reasoningEffort) env.CODEMIE_REASONING_EFFORT = config.reasoningEffort;
-    if (config.haikuModel) env.CODEMIE_HAIKU_MODEL = config.haikuModel;
-    if (config.sonnetModel) env.CODEMIE_SONNET_MODEL = config.sonnetModel;
-    if (config.opusModel) env.CODEMIE_OPUS_MODEL = config.opusModel;
+    // Always emit tier model vars — even when absent — so stale shell values are
+    // overridden during env merge in BaseAgentAdapter (EPMCDME-12779).
+    // Empty string is falsy, so transformEnvVars() correctly skips absent tiers.
+    env.CODEMIE_HAIKU_MODEL = config.haikuModel ?? '';
+    env.CODEMIE_SONNET_MODEL = config.sonnetModel ?? '';
+    env.CODEMIE_OPUS_MODEL = config.opusModel ?? '';
     if (config.timeout) env.CODEMIE_TIMEOUT = String(config.timeout);
     if (config.debug) env.CODEMIE_DEBUG = String(config.debug);