6.5 KiB
Session Continuation Examples
⚠️ CRITICAL: Always Use codex exec
ALL commands in this document use codex exec - this is mandatory in Claude Code.
❌ NEVER: codex resume ... (will fail with "stdout is not a terminal")
✅ ALWAYS: codex exec resume ... (correct non-interactive mode)
Claude Code's bash environment is non-terminal. Plain codex commands will NOT work.
Example 1: Basic Session Continuation
Initial Request
User: "Help me design a queue data structure in Python"
Skill Executes:
codex exec -m gpt-5.1 -s read-only \
-c model_reasoning_effort=high \
"Help me design a queue data structure in Python"
Codex Response: Provides queue design with multiple approaches.
Session Auto-Saved: Codex CLI saves this session automatically.
Follow-Up Request
User: "Continue with that queue - now add thread-safety"
Skill Detects: Continuation keywords ("continue with that")
Skill Executes:
codex exec resume --last
Codex Response: Resumes previous session, maintains context about the queue design, and adds thread-safety implementation building on the previous discussion.
Context Maintained: All previous conversation history is available to Codex.
Example 2: Multi-Turn Iterative Development
Turn 1: Initial Design
User: "Design a REST API for a blog system"
codex exec -m gpt-5.1 -s read-only \
-c model_reasoning_effort=high \
"Design a REST API for a blog system"
Output: API endpoint design, resource modeling, etc.
Turn 2: Add Authentication
User: "Add authentication to that API design"
Skill Executes:
codex exec resume --last
Output: Codex continues from previous API design and adds JWT/OAuth authentication strategy.
Turn 3: Add Error Handling
User: "Now add comprehensive error handling"
Skill Executes:
codex exec resume --last
Output: Codex builds on previous API + auth design and adds error handling patterns.
Turn 4: Implementation
User: "Implement the user authentication endpoint"
Skill Executes:
codex exec resume --last
Output: Codex uses all previous context to implement the auth endpoint with full understanding of the API design.
Result: After 4 turns, you have a complete API with design, auth, error handling, and initial implementation - all with maintained context.
Example 3: Explicit Resume Command
When to Use Interactive Picker
If you have multiple Codex sessions and want to choose which one to continue:
User: "Show me my Codex sessions and let me pick which to resume"
Manual Command (run outside skill):
codex exec resume --last
This opens an interactive picker showing:
Recent Codex Sessions:
1. Queue data structure design (30 minutes ago)
2. REST API for blog system (2 hours ago)
3. Binary search tree implementation (yesterday)
Select session to resume:
Example 4: Resuming After Claude Code Restart
Scenario
- You worked on a queue design with Codex
- Closed Claude Code
- Reopened Claude Code days later
Resume Request
User: "Continue where we left off with the queue implementation"
Skill Executes:
codex exec resume --last
Result: Codex resumes the most recent session (the queue work) with full context maintained across Claude Code restarts.
Why It Works: Codex CLI persists session history independently of Claude Code.
Continuation Keywords
The skill detects continuation requests when you use phrases like:
- "Continue with that"
- "Resume the previous session"
- "Keep going"
- "Add to that"
- "Now add X" (implies building on previous)
- "Continue where we left off"
- "Follow up on that"
Decision Tree: New Session vs. Resume
User makes request
│
├─ Contains continuation keywords?
│ │
│ ├─ YES → Use `codex exec resume --last`
│ │
│ └─ NO → Check context
│ │
│ ├─ References previous Codex work?
│ │ │
│ │ ├─ YES → Use `codex exec resume --last`
│ │ │
│ │ └─ NO → New session: `codex exec -m ... "prompt"`
│
└─ User explicitly says "new" or "fresh"?
│
└─ YES → Force new session even if continuation keywords present
Session History Management
Automatic Save
- Every Codex session is automatically saved by Codex CLI
- No manual session ID tracking needed
- Sessions persist across:
- Claude Code restarts
- Terminal sessions
- System reboots
Accessing History
# Resume most recent (recommended for skill)
codex exec resume --last
# Interactive picker (manual use)
codex exec resume --last
# List sessions (manual use)
codex list
Best Practices
1. Use Clear Continuation Language
Good:
- "Continue with that queue implementation - add unit tests"
- "Resume the API design session and add rate limiting"
Less Clear:
- "Add tests" (ambiguous - new or continue?)
- "Rate limiting" (no continuation context)
2. Build Incrementally
Start with high-level design, then iterate:
- Design (new session)
- Add feature A (resume)
- Add feature B (resume)
- Implement (resume with full context)
3. Leverage Context Accumulation
Each resumed session has ALL previous context:
- Design decisions
- Trade-offs discussed
- Code patterns chosen
- Error handling approaches
This allows Codex to provide increasingly sophisticated, context-aware assistance.
Troubleshooting
"No previous sessions found"
Cause: Codex CLI history is empty (no prior sessions)
Fix: Start a new session first:
codex exec -m gpt-5.1"Design a queue"
Then subsequent "continue" requests will work.
Session Not Resuming Correctly
Symptoms: Resume works but context seems lost
Possible Causes:
- Multiple sessions mixed together
- User explicitly requested "fresh start"
Fix: Use interactive picker to select correct session:
codex exec resume --last
Multiple Sessions Confusion
Scenario: Working on two projects, want to resume specific one
Solution:
- Be explicit: "Resume the queue design session" (skill will use --last)
- Or manually:
codex exec resume --last(orcodex exec resume <session-id>) → pick correct session
Next Steps
- Advanced config: See advanced-config.md
- Basic examples: See basic-usage.md
- Full docs: See ../SKILL.md