feat(opencode): add OpenAI provider support

src/adapters/opencode.test.ts

@@ -26,6 +26,21 @@ describe('opencode adapter', () => {
     expect(models.every(m => m.startsWith('opencode-go/'))).toBe(true);
   });
 
+  it('exposes direct OpenAI models and defaults', () => {
+    const openAiSection = opencodeAdapter.defaultSection('openai');
+    const models = opencodeAdapter.modelsForProvider('openai');
+
+    expect(openAiSection.provider).toBe('openai');
+    expect(openAiSection.build_model).toBe('openai/gpt-5.6-terra');
+    expect(openAiSection.plan_model).toBe('openai/gpt-5.6-sol');
+    expect(openAiSection.agents).toEqual([
+      { template: 'recon', name: 'recon', model: 'openai/gpt-5.6-luna' },
+      { template: 'oracle', name: 'oracle', model: 'openai/gpt-5.6-sol' },
+      { template: 'architect', name: 'architect', model: 'openai/gpt-5.6-sol' },
+    ]);
+    expect(models.every(model => model.startsWith('openai/'))).toBe(true);
+  });
+
   it('mergeHarnessConfig writes opencode.json', () => {
     opencodeAdapter.mergeHarnessConfig(section(), basePath);
     const path = join(basePath, 'opencode.json');

src/adapters/opencode.ts

@@ -13,6 +13,7 @@ const OPENCODE_PROVIDERS: { name: string; value: OpenCodeProvider }[] = [
   { name: 'OpenCode Zen', value: 'opencode-zen' },
   { name: 'OpenCode Go', value: 'opencode-go' },
   { name: 'Amazon Bedrock', value: 'amazon-bedrock' },
+  { name: 'OpenAI', value: 'openai' },
 ];
 
 const PROVIDER_MODELS: Record<OpenCodeProvider, readonly string[]> = {
@@ -55,6 +56,16 @@ const PROVIDER_MODELS: Record<OpenCodeProvider, readonly string[]> = {
     'amazon-bedrock/anthropic-claude-haiku-4-5',
     'amazon-bedrock/anthropic-claude-opus-4-7',
   ],
+  openai: [
+    'openai/gpt-5.6-sol',
+    'openai/gpt-5.6-terra',
+    'openai/gpt-5.6-luna',
+    'openai/gpt-5.5',
+    'openai/gpt-5.4',
+    'openai/gpt-5.4-mini',
+    'openai/gpt-5.4-nano',
+    'openai/gpt-5.3-codex-spark',
+  ],
 };
 
 const DEFAULT_MODELS: Record<OpenCodeProvider, { build: string; plan: string; recon: string; oracle: string; architect: string }> = {
@@ -79,6 +90,13 @@ const DEFAULT_MODELS: Record<OpenCodeProvider, { build: string; plan: string; re
     build: 'amazon-bedrock/anthropic-claude-sonnet-4-5',
     plan: 'amazon-bedrock/anthropic-claude-haiku-4-5',
   },
+  openai: {
+    recon: 'openai/gpt-5.6-luna',
+    oracle: 'openai/gpt-5.6-sol',
+    architect: 'openai/gpt-5.6-sol',
+    build: 'openai/gpt-5.6-terra',
+    plan: 'openai/gpt-5.6-sol',
+  },
 };
 
 export const opencodeAdapter: HarnessAdapter = {

src/commands/init.test.ts

@@ -127,6 +127,29 @@ describe('init', () => {
     expect(existsSync(join(opencodeDir, 'agent/recon.md'))).toBe(true);
   });
 
+  test('prints the OpenAI authentication command after initialization', async () => {
+    inquirerAnswers = {
+      provider: 'openai',
+      build_model: 'openai/gpt-5.6-terra',
+      plan_model: 'openai/gpt-5.6-sol',
+      recon: 'openai/gpt-5.6-luna',
+      oracle: 'openai/gpt-5.6-sol',
+      architect: 'openai/gpt-5.6-sol',
+      confirm: true,
+    };
+    const logs: string[] = [];
+    const originalLog = console.log;
+    console.log = (...args: unknown[]) => logs.push(args.join(' '));
+
+    try {
+      await init({ harness: 'opencode' });
+    } finally {
+      console.log = originalLog;
+    }
+
+    expect(logs).toContain('  opencode auth login --provider openai  # connect your OpenAI account');
+  });
+
   test('throws when --yes is used without --harness', async () => {
     await expect(init({ yes: true })).rejects.toThrow(
       '`--yes` requires `--harness` (claude, opencode, or codex).'

src/commands/init.ts

@@ -93,5 +93,8 @@ export async function init(options: InitOptions): Promise<void> {
 
   console.log(`\nAtelier initialized for ${harness}.`);
   console.log('\nNext step:');
+  if (harness === 'opencode' && section.provider === 'openai') {
+    console.log('  opencode auth login --provider openai  # connect your OpenAI account');
+  }
   console.log('  npx skills add martinffx/atelier  # install skills');
 }

src/services/prompt.test.ts

@@ -116,6 +116,10 @@ describe('prompt', () => {
     expect(() => guardProvider('claude' as unknown as import('../types.js').Provider)).toThrow();
   });
 
+  it('accepts OpenAI as an opencode provider', () => {
+    expect(guardProvider('openai')).toBe('openai');
+  });
+
   it('formatFileList renders exists marker', () => {
     const files = [
       { path: '~/.claude/settings.json', exists: true },

src/services/prompt.ts

@@ -110,7 +110,7 @@ export function formatFileList(files: { path: string; exists: boolean }[]): stri
 }
 
 export function guardProvider(provider: Provider | undefined): OpenCodeConfig['provider'] {
-  if (!provider || !['opencode-zen', 'opencode-go', 'amazon-bedrock'].includes(provider)) {
+  if (!provider || !['opencode-zen', 'opencode-go', 'amazon-bedrock', 'openai'].includes(provider)) {
     throw new InvalidConfigError('A valid provider must be selected for OpenCode');
   }
   return provider as OpenCodeConfig['provider'];

src/types.ts

@@ -7,7 +7,7 @@ export type Harness = typeof HARNESS_NAMES[number];
 export type AgentName = typeof AGENT_NAMES[number];
 
 export type Provider = 'anthropic' | 'opencode-zen' | 'opencode-go' | 'amazon-bedrock' | 'openai';
-export type OpenCodeProvider = 'opencode-zen' | 'opencode-go' | 'amazon-bedrock';
+export type OpenCodeProvider = 'opencode-zen' | 'opencode-go' | 'amazon-bedrock' | 'openai';
 
 export interface ProviderChoice {
   name: string;

src/utils/config.test.ts

@@ -205,6 +205,18 @@ describe('config', () => {
     expect(architect?.model).toBe('opencode-go/deepseek-v4-pro');
   });
 
+  test('opencode config accepts the OpenAI provider', async () => {
+    const { validateConfig } = await import('./config.js');
+    const opencode = opencodeAdapter.defaultSection('openai');
+
+    expect(validateConfig({
+      version: '1.0.0',
+      skills_source: 'martinffx/atelier',
+      skills_path: '~/.agents/skills',
+      opencode,
+    }).opencode?.provider).toBe('openai');
+  });
+
   test('opencode adapter defaultSection defaults to opencode-zen when no provider given', () => {
     const section = opencodeAdapter.defaultSection();
 

src/utils/schemas.ts

@@ -13,7 +13,7 @@ export const SimpleConfigSchema = z.object({
   agents: z.array(AgentSchema).min(1),
 });
 
-export const OPENCODE_PROVIDERS = ['opencode-zen', 'opencode-go', 'amazon-bedrock'] as const;
+export const OPENCODE_PROVIDERS = ['opencode-zen', 'opencode-go', 'amazon-bedrock', 'openai'] as const;
 
 export const OpenCodeConfigSchema = z.object({
   provider: z.enum(OPENCODE_PROVIDERS),