openchamber/packages/web/server/lib/small-model/call.test.js

import fs from 'fs';
import os from 'os';
import path from 'path';
import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';

// readConfig reads merged opencode config layers from disk; mock it so each
// test controls the provider config without touching the filesystem. call.js
// imports only readConfig from shared.js, so the rest of that module is left
// untouched for this file.
vi.mock('../opencode/shared.js', () => ({
  readConfig: vi.fn(),
  readConfigLayers: vi.fn(),
}));

vi.mock('./runtime-providers.js', () => ({ getRuntimeProvider: vi.fn(async () => null) }));

const { callSmallModel } = await import('./call.js');
const { readConfig, readConfigLayers } = await import('../opencode/shared.js');
const { getRuntimeProvider } = await import('./runtime-providers.js');

// Minimal catalog fragment used by the catalog-based base URL resolution case.
const CATALOG = {
  mistral: {
    id: 'mistral',
    name: 'Mistral',
    api: 'https://api.mistral.ai/v1',
    models: {
      'mistral-small-latest': { id: 'mistral-small-latest' },
    },
  },
};

const ok = (content) => ({
  ok: true,
  status: 200,
  json: async () => ({
    choices: [{ message: { content }, finish_reason: 'stop' }],
  }),
  text: async () => JSON.stringify({
    choices: [{ message: { content }, finish_reason: 'stop' }],
  }),
});

const lastCall = (mock) => {
  const [url, init] = mock.mock.calls.at(-1);
  return { url: String(url), init };
};

// Regression coverage for the small-model dispatch to custom OpenAI-compatible
// providers — credential and endpoint resolution, precedence, and non-leakage.
describe('callSmallModel — custom provider config', () => {
  let fetchMock;
  let originalFetch;

  beforeEach(() => {
    fetchMock = vi.fn();
    originalFetch = globalThis.fetch;
    globalThis.fetch = fetchMock;
    readConfig.mockReset();
    readConfigLayers.mockReset();
    // Default: OpenCode knows nothing, so resolution stays file-based.
    getRuntimeProvider.mockReset();
    getRuntimeProvider.mockResolvedValue(null);
  });

  afterEach(() => {
    globalThis.fetch = originalFetch;
    vi.restoreAllMocks();
    delete process.env.OPENCHAMBER_TEST_PROVIDER_KEY;
  });

  describe('config-supplied credentials (no auth.json entry)', () => {
    it('resolves an OpenCode file variable before sending the API key', async () => {
      const secretPath = path.join(os.homedir(), '.secret');
      const originalReadFileSync = fs.readFileSync;
      vi.spyOn(fs, 'readFileSync').mockImplementation((filePath, ...args) => {
        if (filePath === secretPath) return 'sk-file-key\n';
        return originalReadFileSync(filePath, ...args);
      });
      readConfig.mockReturnValue({
        provider: {
          custom: {
            options: { apiKey: '{file:~/.secret}', baseURL: 'https://proxy.example.test/v1' },
          },
        },
      });
      fetchMock.mockResolvedValue(ok('hello'));

      await callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'model',
        prompt: 'hi',
      });

      expect(lastCall(fetchMock).init.headers.Authorization).toBe('Bearer sk-file-key');
      expect(JSON.stringify(fetchMock.mock.calls[0][1])).not.toContain('{file:');
    });

    it('resolves an OpenCode environment variable before sending the API key', async () => {
      process.env.OPENCHAMBER_TEST_PROVIDER_KEY = 'sk-env-key';
      readConfig.mockReturnValue({
        provider: {
          custom: {
            options: { apiKey: '{env:OPENCHAMBER_TEST_PROVIDER_KEY}', baseURL: 'https://proxy.example.test/v1' },
          },
        },
      });
      fetchMock.mockResolvedValue(ok('hello'));

      await callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'model',
        prompt: 'hi',
      });

      expect(lastCall(fetchMock).init.headers.Authorization).toBe('Bearer sk-env-key');
    });

    it('uses apiKey and baseURL from provider config when no auth.json entry exists', async () => {
      readConfig.mockReturnValue({
        provider: {
          custom: {
            options: { apiKey: 'test-key', baseURL: 'https://proxy.example.test/v1' },
          },
        },
      });
      fetchMock.mockResolvedValue(ok('hello'));

      const text = await callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      });

      expect(text).toBe('hello');
      expect(fetchMock).toHaveBeenCalledTimes(1);

      const { url, init } = lastCall(fetchMock);
      // Config baseURL is used, never the hardcoded OpenAI endpoint.
      expect(url).toBe('https://proxy.example.test/v1/chat/completions');
      expect(url).not.toContain('api.openai.com');
      // Config apiKey becomes the bearer credential.
      expect(init.headers.Authorization).toBe('Bearer test-key');
    });

    it('trims a trailing slash from the configured baseURL', async () => {
      readConfig.mockReturnValue({
        provider: {
          custom: { options: { apiKey: 'k', baseURL: 'https://proxy.example.test/v1/' } },
        },
      });
      fetchMock.mockResolvedValue(ok('ok'));

      await callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      });

      expect(lastCall(fetchMock).url).toBe('https://proxy.example.test/v1/chat/completions');
    });

    it('throws "No OpenCode login found for provider" when neither auth.json nor config apiKey exists', async () => {
      readConfig.mockReturnValue({
        provider: { custom: { options: { baseURL: 'https://proxy.example.test/v1' } } },
      });

      const error = await callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      }).then(() => null, (e) => e);

      expect(error).toMatchObject({
        message: 'No OpenCode login found for provider "custom"',
        code: 'no-provider-login',
        statusCode: 401,
        providerID: 'custom',
      });

      // The credential gate fires before any network call.
      expect(fetchMock).not.toHaveBeenCalled();
    });

    it('treats a blank/whitespace apiKey in config as absent', async () => {
      readConfig.mockReturnValue({
        provider: {
          custom: { options: { apiKey: '   ', baseURL: 'https://proxy.example.test/v1' } },
        },
      });

      await expect(callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      })).rejects.toThrow('No OpenCode login found for provider "custom"');
    });
  });

  describe('resolution order when auth.json is also present', () => {
    it('uses the auth.json credential with the config baseURL', async () => {
      readConfig.mockReturnValue({
        provider: { custom: { options: { baseURL: 'https://proxy.example.test/v1' } } },
      });
      fetchMock.mockResolvedValue(ok('done'));

      const text = await callSmallModel({
        auth: { custom: { type: 'api', key: 'authjson-key' } },
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      });

      expect(text).toBe('done');
      const { url, init } = lastCall(fetchMock);
      expect(url).toBe('https://proxy.example.test/v1/chat/completions');
      expect(init.headers.Authorization).toBe('Bearer authjson-key');
    });

    it('prefers the config apiKey over an auth.json credential when both are present (matches OpenCode)', async () => {
      readConfig.mockReturnValue({
        provider: {
          custom: { options: { apiKey: 'config-key', baseURL: 'https://proxy.example.test/v1' } },
        },
      });
      fetchMock.mockResolvedValue(ok('done'));

      await callSmallModel({
        auth: { custom: { type: 'api', key: 'authjson-key' } },
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      });

      // OpenCode's resolveSDK reads options.apiKey first and only falls back to
      // auth.json's key when config has none — so the config key wins and the
      // auth.json credential must never be sent.
      expect(lastCall(fetchMock).init.headers.Authorization).toBe('Bearer config-key');
      expect(JSON.stringify(fetchMock.mock.calls[0][1])).not.toContain('authjson-key');
    });
  });

  describe('openai provider custom baseURL override', () => {
    it('respects provider.openai.options.baseURL over the hardcoded OpenAI endpoint', async () => {
      readConfig.mockReturnValue({
        provider: { openai: { options: { baseURL: 'https://gateway.example.test/v1' } } },
      });
      fetchMock.mockResolvedValue(ok('ok'));

      await callSmallModel({
        auth: { openai: { type: 'api', key: 'sk-openai' } },
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'openai',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      });

      const { url, init } = lastCall(fetchMock);
      expect(url).toBe('https://gateway.example.test/v1/chat/completions');
      expect(url).not.toContain('api.openai.com');
      expect(init.headers.Authorization).toBe('Bearer sk-openai');
    });

    it('falls back to https://api.openai.com/v1 when no openai baseURL override is configured', async () => {
      readConfig.mockReturnValue({});
      fetchMock.mockResolvedValue(ok('ok'));

      await callSmallModel({
        auth: { openai: { type: 'api', key: 'sk-openai' } },
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'openai',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      });

      expect(lastCall(fetchMock).url).toBe('https://api.openai.com/v1/chat/completions');
    });

    it('still requires a credential: a baseURL alone does not authenticate openai', async () => {
      readConfig.mockReturnValue({
        provider: { openai: { options: { baseURL: 'https://gateway.example.test/v1' } } },
      });

      await expect(callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'openai',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      })).rejects.toThrow('No OpenCode login found for provider "openai"');
    });
  });

  describe('catalog-based base URL (no config override)', () => {
    it('uses the catalog api field when no config baseURL is set', async () => {
      readConfig.mockReturnValue({});
      fetchMock.mockResolvedValue(ok('ok'));

      await callSmallModel({
        auth: { mistral: { type: 'api', key: 'mistral-key' } },
        catalog: CATALOG,
        workingDirectory: '/proj',
        providerID: 'mistral',
        modelID: 'mistral-small-latest',
        prompt: 'hi',
      });

      const { url, init } = lastCall(fetchMock);
      expect(url).toBe('https://api.mistral.ai/v1/chat/completions');
      expect(init.headers.Authorization).toBe('Bearer mistral-key');
    });

    it('throws when a non-openai provider has no catalog api and no config baseURL', async () => {
      readConfig.mockReturnValue({});

      await expect(callSmallModel({
        auth: { custom: { type: 'api', key: 'k' } },
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      })).rejects.toThrow('Provider "custom" has no known API base URL');
    });

    // A plugin registers its provider inside the running OpenCode process, so
    // neither the config nor auth.json knows anything about it. This is the
    // case that used to fail with "has no known API base URL" (#2666).
    it('uses the endpoint and credential OpenCode resolved for a plugin provider', async () => {
      readConfig.mockReturnValue({});
      getRuntimeProvider.mockResolvedValue({
        id: 'llmapi',
        apiKey: 'plugin-key',
        baseURL: 'https://api.llmapi.ai/v1',
        anonymousZen: false,
      });
      const fetchMock = vi.fn(async () => ok('done'));
      vi.stubGlobal('fetch', fetchMock);

      await callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'llmapi',
        modelID: 'claude-opus-4-8',
        prompt: 'hi',
      });

      const { url, init } = lastCall(fetchMock);
      expect(url).toBe('https://api.llmapi.ai/v1/chat/completions');
      expect(init.headers.Authorization).toBe('Bearer plugin-key');
    });

    it('keeps the ChatGPT-plan login on its own transport instead of the runtime key', async () => {
      readConfig.mockReturnValue({});
      // OpenCode reports an OAuth access token as `options.apiKey` for openai;
      // api.openai.com answers it with 401, so it must not stand in for the
      // codex path.
      getRuntimeProvider.mockResolvedValue({
        id: 'openai',
        apiKey: 'oauth-access-token',
        baseURL: null,
        anonymousZen: false,
      });

      await expect(callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'openai',
        modelID: 'gpt-5.4-mini',
        prompt: 'hi',
      })).rejects.toMatchObject({ code: 'no-provider-login' });
    });

    it('prefers an explicit config baseURL over the runtime endpoint', async () => {
      readConfig.mockReturnValue({ provider: { custom: { options: { baseURL: 'https://configured.example/v1' } } } });
      getRuntimeProvider.mockResolvedValue({
        id: 'custom',
        apiKey: 'runtime-key',
        baseURL: 'https://runtime.example/v1',
        anonymousZen: false,
      });
      const fetchMock = vi.fn(async () => ok('done'));
      vi.stubGlobal('fetch', fetchMock);

      await callSmallModel({
        auth: { custom: { type: 'api', key: 'auth-key' } },
        catalog: {},
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'm',
        prompt: 'hi',
      });

      expect(lastCall(fetchMock).url).toBe('https://configured.example/v1/chat/completions');
    });
  });

  describe('config-supplied key does not leak', () => {
    // The config-supplied key must stay in-memory: never copied into catalog
    // metadata, the response, or the request body.
    it('does not mutate the catalog or echo the key in the request/response', async () => {
      const catalog = { custom: { id: 'custom', models: {} } };
      const catalogBefore = JSON.parse(JSON.stringify(catalog));
      readConfig.mockReturnValue({
        provider: {
          custom: { options: { apiKey: 'test-key', baseURL: 'https://proxy.example.test/v1' } },
        },
      });
      fetchMock.mockResolvedValue(ok('the answer'));

      const text = await callSmallModel({
        auth: {},
        catalog,
        workingDirectory: '/proj',
        providerID: 'custom',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      });

      // Response text is exactly the model output — no credential echoed back.
      expect(text).toBe('the answer');
      // Catalog object left untouched (key stays in-memory only).
      expect(catalog).toEqual(catalogBefore);

      const { url, init } = lastCall(fetchMock);
      // The key rides only in the Authorization header.
      expect(url).not.toContain('test-key');
      const body = JSON.parse(init.body);
      expect(JSON.stringify(body)).not.toContain('test-key');
    });
  });

  describe('merged config layers', () => {
    it('reads the provider config for the supplied working directory', async () => {
      readConfig.mockReturnValue({
        provider: {
          custom: { options: { apiKey: 'test-key', baseURL: 'https://proxy.example.test/v1' } },
        },
      });
      fetchMock.mockResolvedValue(ok('ok'));

      await callSmallModel({
        auth: {},
        catalog: {},
        workingDirectory: '/path/to/project',
        providerID: 'custom',
        modelID: 'gpt-4o-mini',
        prompt: 'hi',
      });

      // readConfig merges global + project-scoped layers for this directory;
      // confirm callSmallModel passes the working directory straight through.
      expect(readConfig).toHaveBeenCalledWith('/path/to/project');
    });
  });
});

describe('callSmallModel — Google thinking configuration', () => {
  let fetchMock;
  let originalFetch;

  beforeEach(() => {
    fetchMock = vi.fn();
    originalFetch = globalThis.fetch;
    globalThis.fetch = fetchMock;
    readConfig.mockReset();
    readConfig.mockReturnValue({});
  });

  afterEach(() => {
    globalThis.fetch = originalFetch;
  });

  const googleResponse = (text) => ({
    ok: true,
    status: 200,
    json: async () => ({ candidates: [{ content: { parts: [{ text }] } }] }),
  });

  it('uses thinkingLevel for Gemini 3 Flash models', async () => {
    fetchMock.mockResolvedValue(googleResponse('generated commit'));

    const text = await callSmallModel({
      auth: { google: { type: 'api', key: 'google-key' } },
      catalog: {},
      workingDirectory: '/proj',
      providerID: 'google',
      modelID: 'gemini-3.1-flash-lite-preview',
      prompt: 'generate',
    });

    expect(text).toBe('generated commit');
    const body = JSON.parse(lastCall(fetchMock).init.body);
    expect(body.generationConfig.thinkingConfig).toEqual({ thinkingLevel: 'minimal' });
  });

  it('keeps thinkingBudget disabled for Gemini 2.5 Flash models', async () => {
    fetchMock.mockResolvedValue(googleResponse('generated commit'));

    await callSmallModel({
      auth: { google: { type: 'api', key: 'google-key' } },
      catalog: {},
      workingDirectory: '/proj',
      providerID: 'google',
      modelID: 'gemini-2.5-flash-lite',
      prompt: 'generate',
    });

    const body = JSON.parse(lastCall(fetchMock).init.body);
    expect(body.generationConfig.thinkingConfig).toEqual({ thinkingBudget: 0 });
  });
});

describe('callSmallModel — GitHub Copilot endpoint routing', () => {
  let fetchMock;
  let originalFetch;

  const copilotAuth = (overrides = {}) => ({
    'github-copilot': {
      type: 'oauth',
      access: 'test-token',
      refresh: 'test-token',
      expires: 0,
      ...overrides,
    },
  });

  const jsonResponse = (payload, status = 200) => new Response(
    JSON.stringify(payload),
    {
      status,
      headers: { 'Content-Type': 'application/json' },
    },
  );

  const callCopilot = (modelID, options = {}) => callSmallModel({
    auth: copilotAuth(options.auth),
    catalog: {},
    workingDirectory: '/proj',
    providerID: 'github-copilot',
    modelID,
    prompt: 'summarize this diff',
    system: 'Write a commit message',
    maxOutputTokens: 100,
  });

  beforeEach(() => {
    fetchMock = vi.fn();
    originalFetch = globalThis.fetch;
    globalThis.fetch = fetchMock;
    readConfig.mockReset();
    readConfig.mockReturnValue({});
    readConfigLayers.mockReset();
  });

  afterEach(() => {
    globalThis.fetch = originalFetch;
    vi.restoreAllMocks();
  });

  it('routes a model advertising /responses through the Responses API', async () => {
    fetchMock
      .mockResolvedValueOnce(jsonResponse({
        data: [{
          id: 'mai-code-1-flash-picker',
          supported_endpoints: ['/responses'],
        }],
      }))
      .mockResolvedValueOnce(jsonResponse({
        output: [{
          type: 'message',
          content: [{ type: 'output_text', text: 'feat: add summary' }],
        }],
      }));

    await expect(callCopilot('mai-code-1-flash-picker')).resolves.toBe('feat: add summary');

    expect(fetchMock).toHaveBeenCalledTimes(2);
    expect(String(fetchMock.mock.calls[0][0])).toBe('https://api.githubcopilot.com/models');
    expect(String(fetchMock.mock.calls[1][0])).toBe('https://api.githubcopilot.com/responses');
    const body = JSON.parse(fetchMock.mock.calls[1][1].body);
    expect(body).toMatchObject({
      model: 'mai-code-1-flash-picker',
      instructions: 'Write a commit message',
      max_output_tokens: 100,
      stream: false,
      store: false,
      input: [{
        role: 'user',
        content: [{ type: 'input_text', text: 'summarize this diff' }],
      }],
    });
    expect(JSON.stringify(body)).not.toContain('test-token');
  });

  it('prefers /v1/messages when a model advertises multiple endpoints', async () => {
    fetchMock
      .mockResolvedValueOnce(jsonResponse({
        data: [{
          id: 'claude-opus-4.7',
          supported_endpoints: ['/chat/completions', '/responses', '/v1/messages'],
        }],
      }))
      .mockResolvedValueOnce(jsonResponse({
        content: [{ type: 'text', text: 'fix: route Claude correctly' }],
      }));

    await expect(callCopilot('claude-opus-4.7')).resolves.toBe('fix: route Claude correctly');

    expect(String(fetchMock.mock.calls[1][0])).toBe('https://api.githubcopilot.com/v1/messages');
    const body = JSON.parse(fetchMock.mock.calls[1][1].body);
    expect(body).toMatchObject({
      model: 'claude-opus-4.7',
      system: 'Write a commit message',
      max_tokens: 100,
      messages: [{ role: 'user', content: 'summarize this diff' }],
    });
  });

  it('uses /chat/completions when the model advertises the chat endpoint', async () => {
    fetchMock
      .mockResolvedValueOnce(jsonResponse({
        data: [{
          id: 'gpt-5.4-nano',
          supported_endpoints: ['/chat/completions'],
        }],
      }))
      .mockResolvedValueOnce(ok('chore: update summary'));

    await expect(callCopilot('gpt-5.4-nano')).resolves.toBe('chore: update summary');

    expect(String(fetchMock.mock.calls[1][0])).toBe('https://api.githubcopilot.com/chat/completions');
  });

  it('keeps chat completions as the legacy default when endpoint metadata is absent', async () => {
    fetchMock
      .mockResolvedValueOnce(jsonResponse({
        data: [{ id: 'gpt-4o-mini' }],
      }))
      .mockResolvedValueOnce(ok('docs: clarify behavior'));

    await expect(callCopilot('gpt-4o-mini')).resolves.toBe('docs: clarify behavior');

    expect(String(fetchMock.mock.calls[1][0])).toBe('https://api.githubcopilot.com/chat/completions');
  });

  it('uses the enterprise Copilot host for metadata and generation', async () => {
    fetchMock
      .mockResolvedValueOnce(jsonResponse({
        data: [{
          id: 'mai-code-1-flash-picker',
          supported_endpoints: ['/responses'],
        }],
      }))
      .mockResolvedValueOnce(jsonResponse({
        output_text: 'fix: support enterprise routing',
      }));

    await expect(callCopilot('mai-code-1-flash-picker', {
      auth: { enterpriseUrl: 'https://ghe.example.com/' },
    })).resolves.toBe('fix: support enterprise routing');

    expect(String(fetchMock.mock.calls[0][0])).toBe('https://copilot-api.ghe.example.com/models');
    expect(String(fetchMock.mock.calls[1][0])).toBe('https://copilot-api.ghe.example.com/responses');
  });

  it('surfaces Copilot model metadata request failures without generating', async () => {
    fetchMock.mockResolvedValueOnce(jsonResponse({ error: 'unavailable' }, 503));

    await expect(callCopilot('mai-code-1-flash-picker'))
      .rejects.toThrow('GitHub Copilot models request failed with 503');

    expect(fetchMock).toHaveBeenCalledTimes(1);
  });

  it('rejects missing models and unsupported advertised endpoints', async () => {
    fetchMock.mockResolvedValueOnce(jsonResponse({
      data: [{ id: 'different-model', supported_endpoints: ['/responses'] }],
    }));

    await expect(callCopilot('mai-code-1-flash-picker'))
      .rejects.toThrow('GitHub Copilot model "mai-code-1-flash-picker" was not returned by /models');

    fetchMock.mockReset();
    fetchMock.mockResolvedValueOnce(jsonResponse({
      data: [{
        id: 'mai-code-1-flash-picker',
        supported_endpoints: ['/future'],
      }],
    }));

    await expect(callCopilot('mai-code-1-flash-picker'))
      .rejects.toThrow('GitHub Copilot model "mai-code-1-flash-picker" has no supported text endpoint');
    expect(fetchMock).toHaveBeenCalledTimes(1);
  });
});

// Structured output has no single wire format: each provider family needs its
// own request shape and its own extraction, and one family cannot do it at all.
// These lock the per-format translation so a provider is never silently sent a
// schema it will ignore.
describe('callSmallModel — structured output', () => {
  let fetchMock;
  let originalFetch;

  const SCHEMA = {
    type: 'object',
    properties: { title: { type: 'string' } },
    required: ['title'],
    additionalProperties: false,
  };

  beforeEach(() => {
    fetchMock = vi.fn();
    originalFetch = globalThis.fetch;
    globalThis.fetch = fetchMock;
    readConfig.mockReset();
    readConfig.mockReturnValue({});
    readConfigLayers.mockReset();
    readConfigLayers.mockReturnValue({ mergedConfig: {} });
  });

  afterEach(() => {
    globalThis.fetch = originalFetch;
  });

  it('sends a json_schema response_format on OpenAI-compatible chat', async () => {
    fetchMock.mockResolvedValue(ok('{"title":"ok"}'));

    const text = await callSmallModel({
      auth: { openai: { type: 'api', key: 'sk-test' } },
      catalog: {},
      workingDirectory: '/proj',
      providerID: 'openai',
      modelID: 'gpt-5.4-mini',
      prompt: 'summarize',
      responseSchema: SCHEMA,
    });

    expect(text).toBe('{"title":"ok"}');
    const body = JSON.parse(lastCall(fetchMock).init.body);
    expect(body.response_format).toEqual({
      type: 'json_schema',
      json_schema: { name: 'response', strict: true, schema: SCHEMA },
    });
  });

  it('omits response_format entirely when no schema is requested', async () => {
    fetchMock.mockResolvedValue(ok('plain text'));

    await callSmallModel({
      auth: { openai: { type: 'api', key: 'sk-test' } },
      catalog: {},
      workingDirectory: '/proj',
      providerID: 'openai',
      modelID: 'gpt-5.4-mini',
      prompt: 'summarize',
    });

    const body = JSON.parse(lastCall(fetchMock).init.body);
    expect(body.response_format).toBeUndefined();
  });

  it('forces a single tool call on the Anthropic messages API and returns its input', async () => {
    fetchMock.mockResolvedValue({
      ok: true,
      status: 200,
      json: async () => ({
        content: [
          { type: 'text', text: 'thinking out loud' },
          { type: 'tool_use', name: 'response', input: { title: 'ok' } },
        ],
      }),
    });

    const text = await callSmallModel({
      auth: { anthropic: { type: 'api', key: 'sk-ant' } },
      catalog: {},
      workingDirectory: '/proj',
      providerID: 'anthropic',
      modelID: 'claude-haiku-4-5',
      prompt: 'summarize',
      responseSchema: SCHEMA,
    });

    expect(JSON.parse(text)).toEqual({ title: 'ok' });
    const body = JSON.parse(lastCall(fetchMock).init.body);
    expect(body.tool_choice).toEqual({ type: 'tool', name: 'response' });
    expect(body.tools[0].input_schema).toEqual(SCHEMA);
  });

  it('fails loudly when Anthropic answers with prose instead of the tool call', async () => {
    fetchMock.mockResolvedValue({
      ok: true,
      status: 200,
      json: async () => ({ content: [{ type: 'text', text: 'here you go' }] }),
    });

    await expect(callSmallModel({
      auth: { anthropic: { type: 'api', key: 'sk-ant' } },
      catalog: {},
      workingDirectory: '/proj',
      providerID: 'anthropic',
      modelID: 'claude-haiku-4-5',
      prompt: 'summarize',
      responseSchema: SCHEMA,
    })).rejects.toThrow('returned no structured output');
  });

  it('strips JSON Schema keywords Google rejects', async () => {
    fetchMock.mockResolvedValue({
      ok: true,
      status: 200,
      json: async () => ({ candidates: [{ content: { parts: [{ text: '{"title":"ok"}' }] } }] }),
    });

    await callSmallModel({
      auth: { google: { type: 'api', key: 'google-key' } },
      catalog: {},
      workingDirectory: '/proj',
      providerID: 'google',
      modelID: 'gemini-2.5-flash',
      prompt: 'summarize',
      responseSchema: { ...SCHEMA, $schema: 'https://json-schema.org/draft/2020-12/schema' },
    });

    const body = JSON.parse(lastCall(fetchMock).init.body);
    expect(body.generationConfig.responseMimeType).toBe('application/json');
    expect(body.generationConfig.responseSchema).toEqual({
      type: 'object',
      properties: { title: { type: 'string' } },
      required: ['title'],
    });
  });

  it('refuses a schema on the ChatGPT-plan backend instead of returning prose', async () => {
    await expect(callSmallModel({
      auth: { openai: { type: 'oauth', access: 'token', refresh: 'refresh' } },
      catalog: {},
      workingDirectory: '/proj',
      providerID: 'openai',
      modelID: 'gpt-5.4-mini',
      prompt: 'summarize',
      responseSchema: SCHEMA,
    })).rejects.toThrow('does not support structured output');

    expect(fetchMock).not.toHaveBeenCalled();
  });
});