Advanced Usage

This guide covers advanced patterns and techniques for using Codex MCP Tool effectively in complex scenarios.

Working with Large Codebases

Chunked Analysis Strategy

When analyzing large codebases, break down the analysis into manageable chunks:

// Step 1: Get overview
{
  "name": "ask-codex",
  "arguments": {
    "prompt": "provide high-level architecture overview of @src/",
    "model": "gpt-5.1-codex-mini"
  }
}

// Step 2: Deep dive into specific modules
{
  "name": "ask-codex",
  "arguments": {
    "prompt": "analyze @src/core/ in detail",
    "model": "gpt-5.1-codex"
  }
}

// Step 3: Cross-module dependencies
{
  "name": "ask-codex",
  "arguments": {
    "prompt": "map dependencies between @src/core/ and @src/utils/",
    "model": "gpt-5.1-codex-max"
  }
}

Memory-Efficient Processing

For very large files or directories:

// Use changeMode with chunking
{
  "name": "ask-codex",
  "arguments": {
    "prompt": "refactor all TypeScript files in @src/",
    "changeMode": true,
    "model": "gpt-5.1-codex-max"
  }
}

// Fetch chunks as needed
{
  "name": "fetch-chunk",
  "arguments": {
    "cacheKey": "refactor-xyz",
    "chunkIndex": 1
  }
}

Complex Refactoring Patterns

Multi-Stage Refactoring

Execute refactoring in controlled stages:

// Stage 1: Analysis
const analysis = {
  name: 'ask-codex',
  arguments: {
    prompt: 'identify all code smells and anti-patterns in @src/',
    sandboxMode: 'read-only',
  },
};

// Stage 2: Planning
const plan = {
  name: 'brainstorm',
  arguments: {
    prompt: 'create refactoring plan for identified issues',
    methodology: 'convergent',
    existingContext: '[analysis results]',
  },
};

// Stage 3: Implementation
const implement = {
  name: 'ask-codex',
  arguments: {
    prompt: 'implement refactoring plan step by step',
    changeMode: true,
    sandboxMode: 'workspace-write',
    approvalPolicy: 'on-request',
  },
};

Incremental Migration

For framework or library migrations:

// Migrate component by component
const components = ['Button', 'Form', 'Modal', 'Table'];

for (const component of components) {
  // Analyze current implementation
  await mcp.call('ask-codex', {
    prompt: `analyze @src/components/${component}.tsx`,
    sandboxMode: 'read-only',
  });

  // Generate migration
  await mcp.call('ask-codex', {
    prompt: `migrate ${component} from v4 to v5 API`,
    changeMode: true,
    approvalPolicy: 'on-request',
  });

  // Verify migration
  await mcp.call('ask-codex', {
    prompt: `verify ${component} migration is complete`,
    sandboxMode: 'read-only',
  });
}

Advanced Brainstorming Techniques

Iterative Refinement

Build on previous brainstorming sessions:

// Round 1: Generate ideas
const round1 = {
  name: 'brainstorm',
  arguments: {
    prompt: 'innovative features for developer tool',
    methodology: 'divergent',
    ideaCount: 30,
  },
};

// Round 2: Filter and refine
const round2 = {
  name: 'brainstorm',
  arguments: {
    prompt: 'refine top 10 ideas from previous session',
    methodology: 'convergent',
    existingContext: '[round1 results]',
    constraints: 'must be implementable in 2 weeks',
  },
};

// Round 3: Implementation planning
const round3 = {
  name: 'brainstorm',
  arguments: {
    prompt: 'create implementation plan for top 3 ideas',
    methodology: 'design-thinking',
    existingContext: '[round2 results]',
    includeAnalysis: true,
  },
};

Cross-Domain Innovation

Combine multiple domains for creative solutions:

{
  "name": "brainstorm",
  "arguments": {
    "prompt": "apply gaming mechanics to productivity app",
    "methodology": "lateral",
    "domain": "gaming,productivity,psychology",
    "ideaCount": 20
  }
}

Automation Workflows

CI/CD Integration

Integrate Codex MCP Tool into your CI/CD pipeline:

# .github/workflows/code-review.yml
name: Automated Code Review

on:
  pull_request:
    types: [opened, synchronize]

jobs:
  review:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Setup Codex MCP
        run: npm install -g @trishchuk/codex-mcp-tool

      - name: Security Review
        run: |
          echo '{
            "method": "tools/call",
            "params": {
              "name": "ask-codex",
              "arguments": {
                "prompt": "security audit @src/",
                "model": "gpt-5.1-codex-max",
                "sandboxMode": "read-only"
              }
            }
          }' | npx @trishchuk/codex-mcp-tool

      - name: Performance Review
        run: |
          echo '{
            "method": "tools/call",
            "params": {
              "name": "ask-codex",
              "arguments": {
                "prompt": "identify performance bottlenecks @src/",
                "model": "gpt-5.1-codex"
              }
            }
          }' | npx @trishchuk/codex-mcp-tool

Scheduled Maintenance

Automate regular code maintenance tasks:

// Weekly technical debt review
const weeklyReview = async () => {
  // Identify technical debt
  const debt = await mcp.call('ask-codex', {
    prompt: 'identify technical debt in @src/',
    model: 'gpt-5.1-codex-max',
  });

  // Generate improvement plan
  const plan = await mcp.call('brainstorm', {
    prompt: 'prioritize technical debt fixes',
    existingContext: debt,
    constraints: '4 hours per week available',
  });

  // Create tickets
  await createGitHubIssues(plan);
};

Performance Optimization

Model Selection Strategy

Choose the right model for the task:

const selectModel = task => {
  switch (task.type) {
    case 'quick-analysis':
      return 'gpt-5.1-codex-mini'; // Fast, cost-effective

    case 'complex-reasoning':
      return 'gpt-5.1-codex'; // Advanced reasoning

    case 'large-refactoring':
      return 'gpt-5.1-codex-max'; // Maximum context

    default:
      return 'gpt-5.1-codex-mini';
  }
};

// Use in practice
const model = selectModel({ type: 'complex-reasoning' });
await mcp.call('ask-codex', {
  prompt: 'your task',
  model: model,
});

Parallel Processing

Execute independent tasks in parallel:

// Parallel analysis of different modules
const modules = ['auth', 'api', 'database', 'ui'];

const analyses = await Promise.all(
  modules.map(module =>
    mcp.call('ask-codex', {
      prompt: `analyze @src/${module}/`,
      model: 'gpt-5.1-codex-mini',
    })
  )
);

// Combine results
const summary = await mcp.call('ask-codex', {
  prompt: 'synthesize module analyses into system overview',
  existingContext: analyses.join('\n'),
  model: 'gpt-5.1-codex-max',
});

Custom Tool Chains

Building Complex Workflows

Chain multiple tools for sophisticated operations:

class CodexWorkflow {
  async reviewAndRefactor(path) {
    // Step 1: Initial review
    const review = await this.review(path);

    // Step 2: Generate improvement ideas
    const ideas = await this.brainstorm(review);

    // Step 3: Implement top improvements
    const changes = await this.implement(ideas);

    // Step 4: Verify changes
    const verification = await this.verify(changes);

    return { review, ideas, changes, verification };
  }

  async review(path) {
    return mcp.call('ask-codex', {
      prompt: `comprehensive review of @${path}`,
      model: 'gpt-5.1-codex-max',
      sandboxMode: 'read-only',
    });
  }

  async brainstorm(context) {
    return mcp.call('brainstorm', {
      prompt: 'improvement suggestions',
      existingContext: context,
      methodology: 'scamper',
      ideaCount: 10,
    });
  }

  async implement(ideas) {
    return mcp.call('ask-codex', {
      prompt: `implement top 3 improvements: ${ideas}`,
      changeMode: true,
      sandboxMode: 'workspace-write',
      approvalPolicy: 'on-request',
    });
  }

  async verify(changes) {
    return mcp.call('ask-codex', {
      prompt: 'verify changes maintain functionality',
      sandboxMode: 'read-only',
    });
  }
}

Security Best Practices

Secure Code Review

Implement security-focused reviews:

{
  "name": "ask-codex",
  "arguments": {
    "prompt": `Check @src/ for:
      - SQL injection vulnerabilities
      - XSS vulnerabilities
      - Authentication bypasses
      - Insecure deserialization
      - Sensitive data exposure
      - Security misconfigurations
      - Using components with known vulnerabilities
      - Insufficient logging and monitoring`,
    "model": "gpt-5.1-codex-max",
    "sandboxMode": "read-only"
  }
}

Compliance Checking

Ensure code meets compliance requirements:

{
  "name": "ask-codex",
  "arguments": {
    "prompt": "verify @src/ compliance with GDPR, HIPAA, and SOC 2",
    "model": "gpt-5.1-codex-max",
    "sandboxMode": "read-only"
  }
}

Debugging Complex Issues

Root Cause Analysis

Systematic debugging approach:

// Step 1: Reproduce issue
const reproduce = {
  name: 'ask-codex',
  arguments: {
    prompt: 'trace execution path for [error scenario] in @src/',
    model: 'gpt-5.1-codex',
  },
};

// Step 2: Identify root cause
const rootCause = {
  name: 'ask-codex',
  arguments: {
    prompt: 'identify root cause of [error] based on trace',
    model: 'gpt-5.1-codex-max',
  },
};

// Step 3: Generate fixes
const fixes = {
  name: 'brainstorm',
  arguments: {
    prompt: 'possible fixes for [root cause]',
    methodology: 'convergent',
    includeAnalysis: true,
  },
};

Related Resources

• Basic Usage
• API Reference
• Troubleshooting
• FAQ