Test Claude Resume Sid

Test Claude Resume SID

Overview

This skill tests whether Claude Code's --resume <sid> flag preserves the original session ID or creates a new one (fork behavior). This is critical for agent-management systems that need to track sessions by SID across multiple processes.

When to Use

• Verifying that cc --resume <sid> maintains session identity
• Debugging agent-management server assumptions about SID:PID mappings
• Confirming session behavior before implementing agent orchestration
• Testing if multiple resumed processes share the same SID

Quick Start

Run the automated test script:

python ~/.claude/skills/test-claude-resume-sid/scripts/test_resume_sid.py

Options:

• --suffix <name>: Custom suffix for tmux session (default: random)
• --keep: Keep tmux session alive after test for manual inspection

What the Test Does

1. Creates a detached tmux session
2. Runs cc "test prompt" in pane 0
3. Extracts the session ID (SID) from the output
4. Splits into 3 panes (horizontal + vertical split)
5. Runs cc --resume <sid> in panes 1 and 2
6. Extracts SIDs from all 3 panes
7. Reports whether all SIDs match

Expected Results

PASS: All 3 panes show the SAME session ID

• --resume preserves the original SID
• Multiple processes can share one session identity
• Agent-management servers can rely on requested_sid == observed_sid

FAIL: Panes show DIFFERENT session IDs

• --resume created new SIDs (forked)
• Each process has its own session identity
• Agent-management servers must track resume_from_sid vs observed_sid

Manual Test Steps

To run the test manually:

# 1. Create tmux session
tmux new-session -d -s sid-test -x 180 -y 50

# 2. Run initial cc
tmux send-keys -t sid-test:0.0 'cc "Hi, my secret is abc123"' Enter

# 3. Wait ~5 seconds, then capture SID
tmux capture-pane -t sid-test:0.0 -p | grep -oE '[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}'

# 4. Split panes
tmux split-window -h -t sid-test:0.0
tmux split-window -v -t sid-test:0.1

# 5. Resume in new panes (replace <SID> with actual SID)
tmux send-keys -t sid-test:0.1 'cc --resume <SID>' Enter
tmux send-keys -t sid-test:0.2 'cc --resume <SID>' Enter

# 6. Wait ~5 seconds, then capture all panes
tmux capture-pane -t sid-test:0.0 -p | grep -i "agent id"
tmux capture-pane -t sid-test:0.1 -p | grep -i "agent id"
tmux capture-pane -t sid-test:0.2 -p | grep -i "agent id"

# 7. Attach to inspect
tmux attach -t sid-test

Verifying via Logs

To confirm SID:PID mapping in centralized logs:

# Find all PIDs for a given SID
grep "<SID>" ~/centralized-logs/claude/sse_lines.jsonl | \
  python -c "
import sys, json, re
pids = set()
for line in sys.stdin:
    obj = json.loads(line.strip())
    meta = obj.get('metadata', '{}')
    if isinstance(meta, str):
        m = re.search(r'\"pid\":(\d+)', meta)
        if m: pids.add(int(m.group(1)))
for p in sorted(pids): print(p)
"

If resume preserves SID, expect 3+ unique PIDs for the same SID.

Resources

scripts/

• test_resume_sid.py - Automated test script that creates tmux session, runs cc commands, extracts SIDs, and reports results