config-audit/tests/scanners/mcp-config-validator.test.mjs

import { describe, it, beforeEach, afterEach } from 'node:test';
import assert from 'node:assert/strict';
import { resolve, join } from 'node:path';
import { fileURLToPath } from 'node:url';
import { mkdtemp, writeFile, rm } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import { discoverConfigFiles } from '../../scanners/lib/file-discovery.mjs';
import { scan } from '../../scanners/mcp-config-validator.mjs';

const __dirname = fileURLToPath(new URL('.', import.meta.url));
const FIXTURES = resolve(__dirname, '../fixtures');

describe('MCP scanner — healthy project', () => {
  let result;
  beforeEach(async () => {
    const discovery = await discoverConfigFiles(resolve(FIXTURES, 'healthy-project'));
    result = await scan(resolve(FIXTURES, 'healthy-project'), discovery);
  });

  it('returns status ok', () => {
    assert.equal(result.status, 'ok');
  });

  it('reports scanner prefix MCP', () => {
    assert.equal(result.scanner, 'MCP');
  });

  it('scans at least 1 file', () => {
    assert.ok(result.files_scanned >= 1);
  });

  it('has no critical or high findings', () => {
    assert.equal(result.counts.critical, 0);
    assert.equal(result.counts.high, 0);
  });

  it('finding IDs match CA-MCP-NNN pattern', () => {
    for (const f of result.findings) {
      assert.match(f.id, /^CA-MCP-\d{3}$/);
    }
  });

  it('has counts object with all severity levels', () => {
    assert.ok('critical' in result.counts);
    assert.ok('high' in result.counts);
    assert.ok('medium' in result.counts);
    assert.ok('low' in result.counts);
    assert.ok('info' in result.counts);
  });
});

describe('MCP scanner — broken project', () => {
  let result;
  beforeEach(async () => {
    const discovery = await discoverConfigFiles(resolve(FIXTURES, 'broken-project'));
    result = await scan(resolve(FIXTURES, 'broken-project'), discovery);
  });

  it('returns status ok', () => {
    assert.equal(result.status, 'ok');
  });

  it('detects SSE server type', () => {
    assert.ok(result.findings.some(f => f.title.includes('SSE')));
  });

  it('SSE recommendation is info severity', () => {
    const sse = result.findings.find(f => f.title.includes('SSE'));
    assert.equal(sse.severity, 'info');
  });

  it('detects unknown server type', () => {
    assert.ok(result.findings.some(f => f.title.includes('Unknown MCP server type')));
  });

  it('unknown server type is high severity', () => {
    const unknown = result.findings.find(f => f.title.includes('Unknown MCP server type'));
    assert.equal(unknown.severity, 'high');
  });

  it('does NOT flag any trust level — `trust` is not a real .mcp.json field (CC docs verified 2026-06-18)', () => {
    assert.ok(!result.findings.some(f => /trust level/i.test(f.title)),
      'no "Missing trust level"/"Invalid trust level" findings: the field does not exist in the official schema');
  });

  it('detects unreferenced env vars in args', () => {
    assert.ok(result.findings.some(f => f.title.includes('Unreferenced env var')));
  });

  it('detects unknown server fields', () => {
    assert.ok(result.findings.some(f => f.title.includes('Unknown MCP server field')));
  });

  it('has multiple findings', () => {
    assert.ok(result.findings.length >= 5);
  });
});

describe('MCP scanner — stray `trust` field is an unknown field (verify-first, 2026-06-18)', () => {
  let result;
  let tmpRoot;

  beforeEach(async () => {
    tmpRoot = await mkdtemp(join(tmpdir(), 'ca-mcp-trust-'));
    // `trust` is NOT a field in the official .mcp.json schema (verified against
    // code.claude.com/docs/en/mcp + /settings, 2026-06-18). Approval is
    // dialog/settings-based (enableAllProjectMcpServers / enabledMcpjsonServers /
    // disabledMcpjsonServers), never a per-server JSON field.
    const mcp = {
      mcpServers: {
        legacy: { type: 'stdio', command: 'node', args: ['server.mjs'], trust: 'workspace' },
      },
    };
    await writeFile(join(tmpRoot, '.mcp.json'), JSON.stringify(mcp, null, 2) + '\n', 'utf8');
    const discovery = await discoverConfigFiles(tmpRoot);
    result = await scan(tmpRoot, discovery);
  });

  afterEach(async () => {
    if (tmpRoot) await rm(tmpRoot, { recursive: true, force: true });
  });

  it('flags `trust` as an unknown MCP server field', () => {
    const f = result.findings.find(x => x.title.includes('Unknown MCP server field')
      && /trust/.test(x.description || ''));
    assert.ok(f, 'a `trust` field must now be reported as an unknown field');
  });

  it('emits no "trust level" findings at all', () => {
    assert.ok(!result.findings.some(x => /trust level/i.test(x.title)),
      'the invented trust-level checks must be gone');
  });
});

describe('MCP scanner — `alwaysLoad` is a valid field (v5.10 B4, verify-first 2026-06-23)', () => {
  let result;
  let tmpRoot;

  beforeEach(async () => {
    tmpRoot = await mkdtemp(join(tmpdir(), 'ca-mcp-alwaysload-'));
    // alwaysLoad exempts a server from MCP tool-schema deferral (CC v2.1.121+).
    // Verified against code.claude.com/docs/en/mcp.md#exempt-a-server-from-deferral.
    const mcp = {
      mcpServers: {
        core: { type: 'http', url: 'https://mcp.example.com/mcp', alwaysLoad: true },
      },
    };
    await writeFile(join(tmpRoot, '.mcp.json'), JSON.stringify(mcp, null, 2) + '\n', 'utf8');
    const discovery = await discoverConfigFiles(tmpRoot);
    result = await scan(tmpRoot, discovery);
  });

  afterEach(async () => {
    if (tmpRoot) await rm(tmpRoot, { recursive: true, force: true });
  });

  it('does NOT flag `alwaysLoad` as an unknown MCP server field', () => {
    const f = result.findings.find(x => x.title.includes('Unknown MCP server field')
      && /alwaysLoad/.test(x.description || ''));
    assert.equal(f, undefined, 'alwaysLoad is a valid field and must not be flagged');
  });
});

describe('MCP scanner — env-var false positives (CC 2.1.139/2.1.142, Batch 1)', () => {
  let tmpRoot;
  let envFindings;

  beforeEach(async () => {
    tmpRoot = await mkdtemp(join(tmpdir(), 'ca-mcp-env-'));
    const mcp = {
      mcpServers: {
        proj: {
          type: 'stdio',
          command: 'node',
          // CLAUDE_PROJECT_DIR is auto-injected (CC 2.1.139); ${VAR%…}/${VAR:-…}
          // are POSIX expansions CC resolves (2.1.142) — none need an env block.
          args: ['${CLAUDE_PROJECT_DIR}/server.mjs', '--root', '${HOME%/}', '--cfg', '${CONFIG_DIR:-/etc}'],
        },
        legacy: {
          type: 'stdio',
          command: 'node',
          args: ['${REAL_MISSING}'],
        },
      },
    };
    await writeFile(join(tmpRoot, '.mcp.json'), JSON.stringify(mcp, null, 2) + '\n', 'utf8');
    const discovery = await discoverConfigFiles(tmpRoot);
    const result = await scan(tmpRoot, discovery);
    envFindings = result.findings.filter(f => f.title === 'Unreferenced env var in args');
  });

  afterEach(async () => {
    if (tmpRoot) await rm(tmpRoot, { recursive: true, force: true });
  });

  it('does NOT flag ${CLAUDE_PROJECT_DIR} (auto-injected runtime var)', () => {
    const f = envFindings.find(x => /CLAUDE_PROJECT_DIR/.test(x.description || ''));
    assert.equal(f, undefined, 'CLAUDE_PROJECT_DIR must be allowlisted');
  });

  it('does NOT flag POSIX expansions ${VAR%…} / ${VAR:-…}', () => {
    const f = envFindings.find(x => /HOME|CONFIG_DIR/.test(x.description || ''));
    assert.equal(f, undefined, 'POSIX operator expansions are not env-var references');
  });

  it('STILL flags a genuine bare unreferenced var', () => {
    assert.equal(envFindings.length, 1,
      `expected exactly REAL_MISSING; got: ${envFindings.map(f => f.description).join(' | ')}`);
    assert.match(envFindings[0].description || '', /REAL_MISSING/);
  });
});

describe('MCP scanner — empty project', () => {
  let result;
  beforeEach(async () => {
    const discovery = await discoverConfigFiles(resolve(FIXTURES, 'empty-project'));
    result = await scan(resolve(FIXTURES, 'empty-project'), discovery);
  });

  it('returns skipped status', () => {
    assert.equal(result.status, 'skipped');
  });

  it('has 0 findings', () => {
    assert.equal(result.findings.length, 0);
  });
});

describe('MCP scanner — minimal project', () => {
  let result;
  beforeEach(async () => {
    const discovery = await discoverConfigFiles(resolve(FIXTURES, 'minimal-project'));
    result = await scan(resolve(FIXTURES, 'minimal-project'), discovery);
  });

  it('returns skipped when no .mcp.json', () => {
    assert.equal(result.status, 'skipped');
  });

  it('has 0 findings', () => {
    assert.equal(result.findings.length, 0);
  });
});