# Test Claude Resume Sid

> Test whether Claude Code --resume preserves the session ID (SID) or creates a new one. This skill should be used when verifying agent session behavior, debugging agent-management systems, or confirming that resuming a session maintains the same SID across multiple processes. Triggers on requests like "test resume sid", "verify session preservation", or "check if resume keeps the same session ID".

- Skill: `tankygranny05/test-claude-resume-sid` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tankygranny05/test-claude-resume-sid`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tankygranny05/test-claude-resume-sid/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: tankygranny05 (https://skillmd.com/u/tankygranny05)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/tankygranny05/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:

```bash
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:

```bash
# 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:

```bash
# 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