Claude-Codex Collaboration

Transfer context between Claude Code and Codex CLI using Byterover as shared memory for collaborative development workflows.

Purpose

Enable seamless collaboration between two AI agents by using Byterover MCP as a persistent shared memory layer. Claude Code creates architectural plans and implementations, then directly invokes Codex CLI for expert architectural review and code validation. All knowledge persists in Byterover, allowing both agents to access the same context. The entire workflow is automated - Claude Code runs Codex directly via the Bash tool without requiring manual user intervention.

When to Use This Skill

Invoke this skill when:

• Architectural review from Codex is desired before implementing a feature
• Code validation from Codex is needed after implementation
• Complex features benefit from multi-agent review before coding
• Building a knowledge base of validated implementation patterns
• Working on projects where quality assurance through peer review is valuable

Workflow

Phase 1: Planning & Review

Step 1: Create Architectural Plan

When the user requests a feature, create a comprehensive architectural plan that includes:

• Context about the problem being solved
• Proposed technical approach with code examples
• Key architectural decisions and rationale
• Open questions or areas where Codex's expertise would be valuable
• Technologies and libraries being considered

Structure the plan clearly with markdown sections for easy review.

Step 2: Store Plan in Byterover

Store the plan using the Byterover MCP tool with rich, searchable content:

mcp__byterover-mcp__byterover-store-knowledge({
  messages: `
**ARCHITECTURAL PLAN: [Feature Name]**
Collaboration between Claude Code and Codex CLI
Status: AWAITING_REVIEW

## Problem Statement
[Clear description of what needs to be built and why]

## Proposed Solution

### Technical Approach
[Detailed technical design with code examples]

### Key Decisions
[Important architectural choices and their rationale]

### Technologies
[Libraries, frameworks, and tools being used]

## Questions for Review
1. [Specific question for Codex to address]
2. [Another area where expert feedback is valuable]

## Implementation Plan
[Step-by-step breakdown of how this will be built]

---
Task: [Feature name/description for search retrieval]
Agent: Claude Code
Date: [Current date]
`
})

Key principles:

• Include rich context for semantic search retrieval
• Use clear section headers for easy parsing
• Make the content self-contained and understandable
• Include specific questions to guide Codex's review

Step 3: Invoke Codex Directly

IMPORTANT: Wait 30 seconds after storing the plan in Byterover before invoking Codex, as Byterover processes memories asynchronously. Inform the user about this wait time.

Then use the Bash tool to run Codex directly from Claude Code:

Bash({
  command: `codex exec "Use the byterover-retrieve-knowledge tool to search for the latest architectural plan about [feature description]. Review the technical approach, identify potential issues, and provide detailed feedback. Store your review in Byterover using byterover-store-knowledge."`,
  description: "Run Codex to review architectural plan",
  timeout: 300000  // 5 minutes for Codex to complete
})

Important considerations:

• Wait 30 seconds after storing plan before invoking Codex (Byterover indexing delay)
• Use a generous timeout (5+ minutes) as Codex may need time to retrieve, analyze, and store feedback
• Inform the user that Codex is running in the background
• The command should be self-contained with all necessary instructions

Step 4: Codex Retrieves and Reviews

Codex will automatically:

1. Use byterover-retrieve-knowledge to find the plan
2. Analyze the architectural approach
3. Identify concerns, risks, and improvement opportunities
4. Store comprehensive feedback in Byterover

Codex's review typically includes:

• Strengths of the proposed approach
• Potential issues or risks identified
• Specific recommendations for improvement
• Answers to the open questions
• Overall verdict (approve, iterate, or reconsider)

Phase 2: Implementation

Step 5: Retrieve Codex's Feedback

After Codex completes (wait another 30 seconds for Byterover to index the feedback), retrieve the feedback:

mcp__byterover-mcp__byterover-retrieve-knowledge({
  query: "[feature description] Codex review architectural feedback",
  limit: 3
})

Use a descriptive query that combines:

• The feature/task being worked on
• Keywords like "Codex review" or "feedback"
• Any identifying terms from the original plan

Byterover uses semantic search, so conceptually similar queries will find related memories.

Step 6: Implement with Improvements

Analyze Codex's feedback and implement the feature incorporating:

• Recommended architectural improvements
• Solutions to identified risks
• Answers to open questions
• Best practices suggested by Codex

Create clean, well-tested code that addresses all concerns raised in the review.

Step 7: Store Implementation Summary

After implementation, store a summary in Byterover:

mcp__byterover-mcp__byterover-store-knowledge({
  messages: `
**IMPLEMENTATION COMPLETE: [Feature Name]**
Collaboration between Claude Code and Codex CLI
Status: READY_FOR_VALIDATION

## What Was Built
[Overview of the implementation]

## Files Created/Modified
- path/to/file1.ts - [Description]
- path/to/file2.ts - [Description]
- path/to/test.ts - [Description]

## Codex Feedback Addressed
✅ [Specific concern from review] - [How it was addressed]
✅ [Another concern] - [Solution implemented]
✅ [Recommendation] - [How it was incorporated]

## Key Implementation Details
[Important technical decisions made during implementation]

## Testing
[Test coverage and approach]

---
Task: [Feature name/description for search retrieval]
Agent: Claude Code
Date: [Current date]
`
})

Phase 3: Validation (Optional)

Step 8: Invoke Codex for Validation

Use the Bash tool to run Codex validation directly:

Bash({
  command: `codex exec "Use the byterover-retrieve-knowledge tool to search for the completed implementation of [feature description]. Review the actual code files listed and validate the implementation quality. Store validation results in Byterover using byterover-store-knowledge."`,
  description: "Run Codex to validate implementation",
  timeout: 300000  // 5 minutes for validation
})

Inform the user that Codex is performing validation in the background.

Step 9: Codex Validates Implementation

Codex will automatically:

1. Retrieve the implementation summary from Byterover
2. Read the actual code files listed
3. Validate code quality, patterns, and best practices
4. Verify that review feedback was properly addressed
5. Store validation results in Byterover

Step 10: Address Validation Feedback (If Needed)

If Codex identifies issues during validation:

1. Retrieve validation feedback from Byterover
2. Address any remaining concerns
3. Update the implementation
4. Store a final summary noting all improvements

Phase 4: Knowledge Extraction

Step 11: Extract Reusable Patterns (Optional)

After successful collaboration, extract validated patterns for future reuse:

mcp__byterover-mcp__byterover-store-knowledge({
  messages: `
**VALIDATED PATTERN: [Pattern Name]**
Production-Ready Implementation Pattern
Validated through Claude-Codex Collaboration

## Pattern Overview
[Description of the reusable pattern]

## Implementation Code
\`\`\`typescript
[Complete, working code example]
\`\`\`

## Key Decisions
- [Important architectural decision]
- [Best practice applied]
- [Performance consideration]

## Use Cases
- [When to use this pattern]
- [What problems it solves]

## Lessons Learned
[Important insights from the collaboration]

---
Pattern validated by: Codex architectural review
Implemented by: Claude Code
Date: [Current date]
`
})

These patterns become searchable knowledge for future projects.

Best Practices

Writing Plans for Review

Create plans that are:

• Self-contained - Include all necessary context
• Specific - Provide concrete code examples
• Questionable - Identify areas where expert input is valuable
• Structured - Use clear sections and headers

Querying Byterover

Construct queries that:

• Combine multiple terms - Use feature name + keywords like "plan" or "review"
• Are descriptive - Include enough context for semantic matching
• Are flexible - Try variations if initial query doesn't return expected results

Examples:

// Good queries
query: "rate limiting Express API architectural plan"
query: "Codex review authentication implementation"
query: "validated pattern Redis caching"

// Less effective queries
query: "plan"  // Too generic
query: "auth"  // Too vague

Storing in Byterover

Store memories that are:

• Rich in context - Include enough information for semantic search
• Clearly labeled - Use descriptive titles and sections
• Self-documenting - Readable without external context
• Searchable - Include keywords relevant to future retrieval

Handling Retrieval Issues

If Byterover doesn't return expected results:

1. Broaden the query - Use more general terms
2. Increase the limit - Try limit: 5 or limit: 10
3. Wait for processing - Memories are indexed asynchronously (20-30 seconds)
4. Try alternative keywords - Use synonyms or related concepts

Working with Codex

When invoking Codex directly via Bash:

1. Use generous timeouts - Set timeout to 300000ms (5 minutes) or more
2. Provide complete commands - Include full syntax with MCP tool names in the exec string
3. Inform the user - Let them know Codex is running in the background
4. Wait for completion - Allow Codex to finish before retrieving results from Byterover
5. Handle errors gracefully - If Codex fails, check the error output and retry if needed

Bundled Resources

scripts/collaborate.sh

Helper script (optional, no longer required for automated workflow):

Since Claude Code now invokes Codex directly via Bash, the helper script is optional. However, it can still be useful for:

• Tracking collaboration sessions with unique identifiers
• Manual invocation of Codex if needed
• Debugging collaboration workflows

Usage examples:

# Generate unique identifier
./collaborate.sh session

# Get Codex review command (for manual use)
./collaborate.sh codex-review [identifier]

# Get Codex validation command (for manual use)
./collaborate.sh codex-validate [identifier]

# Show help
./collaborate.sh help

references/example-session.md

Complete walkthrough of a realistic collaboration session implementing rate limiting for an Express API. Review this file to see:

• How to structure plans for effective review
• What kind of feedback Codex typically provides
• How to incorporate review feedback into implementation
• Complete flow from planning through validation
• Example of extracting reusable patterns

Load this reference when users need concrete examples of the collaboration workflow.

Troubleshooting

Cannot Retrieve Previous Memory

Symptoms: Byterover query returns no results or wrong results

Solutions:

1. Use more descriptive query terms combining feature name with keywords
2. Increase the limit parameter to see more results
3. Wait 30 seconds after storing for indexing to complete
4. Try alternative query terms or broader concepts

Codex Cannot Access Byterover

Symptoms: Codex reports inability to use Byterover tools

Solutions:

1. Verify Codex has Byterover MCP configured: codex mcp list
2. Explicitly instruct Codex to use MCP tools in the command
3. Check Byterover credentials are configured in Codex

Semantic Search Returns Unexpected Results

Symptoms: Query returns memories from different projects or tasks

Solutions:

1. Make stored memories more distinctive with unique identifying information
2. Use very specific query terms
3. Include more context in queries
4. Store richer, more detailed content in Byterover

Limitations

No Metadata Tagging

Byterover uses semantic search without metadata tags or labels. Work around this by:

• Embedding identifying information directly in content
• Using consistent formatting and section headers
• Including rich context in every stored memory
• Creating unique, descriptive content that stands out semantically

Semantic Search Uncertainty

Semantic matching may return similar but unintended memories. Mitigate this by:

• Using highly specific, distinctive content
• Including multiple identifying terms in queries
• Verifying retrieved content matches expectations
• Storing detailed, unique information for each task

Asynchronous Processing

Memories take 20-30 seconds to become searchable after storage. Handle this by:

• Waiting briefly after storing before attempting retrieval
• Informing users about the processing delay
• Using the time to provide context to users about next steps

Value Delivered

This skill enables:

• Higher quality implementations - Plans reviewed before coding catches issues early
• Learning from expertise - Codex's architectural insights improve decision-making
• Persistent knowledge - All decisions and patterns stored for future reference
• Automated collaboration - Claude Code invokes Codex directly without manual intervention
• Cross-agent collaboration - Leverage strengths of both Claude and Codex seamlessly
• Pattern library building - Validated implementations become reusable assets

The fully automated collaboration workflow consistently produces better outcomes than either agent working alone, with the added benefit of building a searchable knowledge base of validated architectural decisions and implementation patterns. Users benefit from expert-level code review without any manual handoff steps.