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?

Codex - tool usage

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:

Detailed Format Documentation

For complete format specifications, see:

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

migrating from codex and claude code

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