Get Session ID Skill

Purpose: The session ID is automatically available at session start via the echo-session-id.sh hook.

How It Works:

• The echo-session-id.sh hook is registered for SessionStart events
• When the session starts, the hook automatically injects the session ID into context
• The session ID appears in system reminders as: ✅ Session ID: {uuid}
• No manual invocation required

When to Use This Skill:

• The session ID is already available - just look for it in the SessionStart system reminders
• Use this skill documentation to understand how the session ID is provided
• Reference when coordinating with hooks that use session IDs

How Session IDs Work

Claude Code assigns a unique session ID (UUID v4) to each conversation session. This ID is used for:

• Naming conversation history files: /home/node/.config/projects/-workspace/{session-id}.jsonl
• Session-specific TODO list tracking
• Hook coordination across tools
• Task ownership in multi-instance scenarios

Automatic Injection via SessionStart Hook

The echo-session-id.sh hook is registered in .claude/settings.json for SessionStart events.

How it works:

1. Claude Code invokes SessionStart hooks when the session starts OR resumes after compaction
2. echo-session-id.sh reads stdin JSON from Claude Code
3. Extracts session_id field using jq
4. Outputs hookSpecificOutput with formatted session ID
5. Claude Code injects this into context as a system reminder

Output injected into context:

✅ Session ID: b6933609-ab67-467e-af26-e48c3c8c129e

Usage Examples

Example 1: Get Current Session ID

The session ID is automatically available in SessionStart system reminders. Look for:

✅ Session ID: b6933609-ab67-467e-af26-e48c3c8c129e

No manual execution needed - it's already in your context!

Example 2: Use Session ID for File Operations

After getting the session ID, you can use it to:

# Access conversation history
cat /home/node/.config/projects/-workspace/{session-id}.jsonl | jq -r 'select(.type == "message")'

# Find session-specific TODO list
find /home/node/.config/todos/ -name "*${SESSION_ID}*"

# Check task ownership
jq -r --arg sid "$SESSION_ID" 'select(.session_id == $sid)' /workspace/tasks/*/task.json

Integration with Hooks

The session ID from this skill matches the session ID that hooks receive via stdin:

# Hooks can use echo-session-id.sh to get formatted output
SESSION_OUTPUT=$(cat | /workspace/.claude/hooks/echo-session-id.sh)
echo "$SESSION_OUTPUT" | jq -r '.hookSpecificOutput'

# Or extract directly from stdin JSON
SESSION_ID=$(cat | jq -r '.session_id')

Both methods read from the same stdin JSON provided by Claude Code.

Related

• echo-session-id.sh: Script that outputs session ID from Claude Code stdin JSON
• read-conversation-history: Skill that uses session ID to access conversation
• hook-logger.sh: Library that uses session ID for session-specific logging

Implementation Details

The echo-session-id.sh script:

• Reads JSON from stdin (provided by Claude Code)
• Extracts session_id field using jq
• Outputs JSON with hookSpecificOutput field
• Requires jq to be installed (standard in Claude Code environment)

Script Location: /workspace/.claude/hooks/echo-session-id.sh