Migrating from Codex and Claude Code

This skill helps you discover, search, and extract useful information from historical Claude Code and OpenAI Codex conversations stored on the user's machine.

When to Use This Skill

• During /init to bootstrap agent memory with project context
• When the user asks about their previous coding sessions
• To understand coding patterns, preferences, or project history
• To find context about a specific project or problem the user worked on before

Scripts

This skill includes ready-to-use scripts for common operations:

Script	Purpose
scripts/detect.sh	Detect available history and show summary
scripts/list-sessions.sh	List sessions for a project
scripts/search.sh	Search across all history by keyword
scripts/view-session.sh	View a session in readable format

Quick Start

# Detect what history data exists
./scripts/detect.sh

# List sessions for current project
./scripts/list-sessions.sh claude
./scripts/list-sessions.sh codex

# Search for a keyword across all history
./scripts/search.sh "database migration"
./scripts/search.sh "auth" --claude --project /path/to/project

# View a specific session
./scripts/view-session.sh ~/.claude/projects/-path-to-project/session.jsonl
./scripts/view-session.sh session.jsonl --tools --thinking

Data Locations

Claude Code (~/.claude/)

Path	Contents
history.jsonl	Global prompt history (all projects) - always available
projects/<encoded-path>/	Per-project conversation sessions - may not exist for older projects
projects/<encoded-path>/sessions-index.json	Quick session metadata lookup
projects/<encoded-path>/<session-uuid>.jsonl	Full conversation history
settings.json	User preferences (model, plugins)

Path Encoding: Claude encodes project paths by replacing / with -:

• /Users/foo/repos/myproject → -Users-foo-repos-myproject

Important: Session files may not exist for older projects (cleaned up or not persisted). In this case, history.jsonl still contains the user's prompts but not full conversations. The scripts will automatically fall back to searching history.jsonl.

OpenAI Codex (~/.codex/)

Path	Contents
history.jsonl	Global prompt history — uses .ts (seconds) and .text fields (NOT .timestamp/.display)
sessions/<year>/<month>/<day>/rollout-*.jsonl	Session files by date
config.toml	User config (model, trusted projects)

Important format difference: Codex uses .ts (seconds) and .text, while Claude uses .timestamp (milliseconds) and .display. Adjust jq queries accordingly.

Quick Searches

Find Sessions for Current Project

# For Claude Code - encode current path
ENCODED=$(pwd | sed 's|/|-|g')
ls ~/.claude/projects/$ENCODED/ 2>/dev/null

# Check sessions index for quick metadata
cat ~/.claude/projects/$ENCODED/sessions-index.json 2>/dev/null | jq '.entries[] | {firstPrompt, messageCount, modified}'

# If session files don't exist, search history.jsonl instead
cat ~/.claude/history.jsonl | jq --arg p "$(pwd)" 'select(.project == $p)'

Search by Project Name (Fallback)

When session files don't exist (older/cleaned up projects), search history.jsonl:

# Search by exact project path
cat ~/.claude/history.jsonl | jq 'select(.project == "/path/to/project")'

# Search by project name (partial match)
cat ~/.claude/history.jsonl | jq 'select(.project | contains("project-name"))'

# List all prompts for a project
cat ~/.claude/history.jsonl | jq -r 'select(.project | contains("myproject")) | "\(.timestamp / 1000 | strftime("%Y-%m-%d %H:%M"))  \(.display[0:80])..."'

Search Prompt History

# Claude - search all prompts
cat ~/.claude/history.jsonl | jq 'select(.display | test("keyword"; "i"))' 

# Codex - search all prompts (.text field, .ts in seconds)
cat ~/.codex/history.jsonl | jq 'select(.text | test("keyword"; "i"))'

Find User Messages in Sessions

# Claude - extract user messages from a session
cat ~/.claude/projects/<path>/<session>.jsonl | jq 'select(.type == "user") | .message.content'

# Codex - extract user messages from a session  
cat ~/.codex/sessions/<path>/rollout-*.jsonl | jq 'select(.type == "event_msg" and .payload.type == "user_message") | .payload.message'

Analyze Tool Usage Patterns

# Claude - what tools does the user's assistant use most?
cat ~/.claude/projects/<path>/<session>.jsonl | jq 'select(.type == "assistant") | .message.content[]? | select(.type == "tool_use") | .name' | sort | uniq -c | sort -rn

# Codex - tool usage
cat ~/.codex/sessions/<path>/rollout-*.jsonl | jq 'select(.type == "response_item" and .payload.type == "function_call") | .payload.name' | sort | uniq -c | sort -rn

Extracting Context for Memory Blocks

Projects the User Has Worked On

# Claude - list all projects with activity counts
cat ~/.claude/history.jsonl | jq -s 'group_by(.project) | map({project: .[0].project, count: length}) | sort_by(-.count)'

Recent Session Summaries

Claude sessions may contain summary entries:

cat ~/.claude/projects/<path>/<session>.jsonl | jq 'select(.type == "summary") | .summary'

Common Workflows/Commands

Look for patterns in Bash tool calls:

cat ~/.claude/projects/<path>/<session>.jsonl | jq 'select(.type == "assistant") | .message.content[]? | select(.type == "tool_use" and .name == "Bash") | .input.command' | head -20

Detailed Format Documentation

For complete format specifications, see:

• references/claude-format.md - Claude Code JSONL structure
• references/codex-format.md - OpenAI Codex JSONL structure