# Claude Speed Test

> Benchmark Claude Code startup/response time across different CLAUDE_CONFIG_DIR locations. Use when user asks to test Claude speed, benchmark config dirs, compare startup times, or measure latency.

- Skill: `tankygranny05/claude-speed-test` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tankygranny05/claude-speed-test`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tankygranny05/claude-speed-test/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/claude-speed-test

---


# Claude Speed Test

Benchmark Claude Code response time across different `CLAUDE_CONFIG_DIR` locations to find the fastest configuration.

## Quick Start

```bash
# Run 3 trials (default)
python ~/.claude/skills/claude-speed-test/benchmark.py

# Run 10 trials
python ~/.claude/skills/claude-speed-test/benchmark.py 10

# Run without auto-cleanup (keep session files for inspection)
python ~/.claude/skills/claude-speed-test/benchmark.py 5 --no-cleanup
```

## What It Tests

By default, benchmarks these 2 configurations:

| Config | Description |
|--------|-------------|
| `~/.claude` | Default Claude config dir |
| `/tmp/claude-sessions` | Fresh/isolated config dir |

## Key Parameters

- **CLAUDE_CODE_EFFORT_LEVEL=0**: Minimizes agent thinking time for consistent measurements
- **cwd=/tmp/tests**: Isolated working directory so test sessions go to `-private-tmp-tests` folder
- **UUIDv7 in prompt**: Each run has unique ID for traceability (`chatId=<uuid7>`)

## Output

```
Trial 1: ~/.claude (default)    = 5.51s
Trial 1: /tmp/claude-sessions   = 4.35s
...
============================================================
SUMMARY
============================================================
Config                   Mean      Std      Min      Max
------------------------------------------------------------
~/.claude (default)     5.25s    0.28s    4.90s    5.72s
/tmp/claude-sessions    4.47s    0.37s    4.06s    5.41s
------------------------------------------------------------
Fastest: /tmp/claude-sessions (4.47s)
```

## Log File

Each run is logged to `benchmark_runs.jsonl` (in the script directory) with:
- `run_id`: UUIDv7 for tracing
- `config_dir`, `config_label`: Which config was tested
- `prompt`: Full prompt sent (includes chatId)
- `cwd`: Working directory used
- `env_vars`: Environment variables set
- `start_time`, `end_time`, `elapsed_seconds`: Timing data
- `stdout`, `stderr`, `exit_code`: Response data

## Auto-Cleanup

By default, the script:
1. **Pre-cleanup**: Deletes previous test sessions before running
2. **Post-cleanup**: Deletes test sessions after running

Test sessions are stored in `-private-tmp-tests` folders (based on cwd `/tmp/tests`).

To disable cleanup: `--no-cleanup`

## Customizing Configurations

Edit `CONFIG_OPTIONS` in `benchmark.py`:

```python
CONFIG_OPTIONS = [
    {"dir": None, "label": "~/.claude (default)"},
    {"dir": "/tmp/claude-sessions", "label": "/tmp/claude-sessions"},
    {"dir": "/tmp/my-custom-dir", "label": "my-custom"},  # Add your own
]
```

---

## OAuth / Authentication

New config directories need OAuth tokens to authenticate. Two methods:

### Method 1: Copy Existing Token (Recommended)

Copy `oauth_token_dump.json` from a working config dir:

```bash
# Create new config dir
mkdir -p /tmp/new-config-dir

# Copy OAuth token from an existing working config
cp ~/.claude/oauth_token_dump.json /tmp/new-config-dir/
```

**Token location**:
- `~/.claude/oauth_token_dump.json`

### Method 2: Generate New Token (Requires Claude Code 2.0.42)

If no token exists, generate one using Claude Code **version 2.0.42** which supports `CLAUDE_CODE_ENABLE_OAUTH_TOKEN_DUMP`:

```bash
# Path to Claude Code 2.0.42
CLAUDE_2042=~/swe/claude-code-2.0.42/cli.js

# Generate token dump (runs a quick session)
CLAUDE_CODE_ENABLE_OAUTH_TOKEN_DUMP=1 \
  CLAUDE_CONFIG_DIR=/tmp/new-config-dir \
  $CLAUDE_2042 -p "OAuth refresh ping"

# Verify token was created
cat /tmp/new-config-dir/oauth_token_dump.json | python -m json.tool
```

**Note:** This requires `~/swe/claude-code-2.0.42/cli.js` to exist. Newer versions (2.1.x) removed this feature.

### Token Structure

```json
{
  "event": "G5_store_load",
  "ts": "2025-11-15T12:34:56.789Z",
  "claudeAiOauth": {
    "accessToken": "sk-ant-oat01-...",
    "refreshToken": "sk-ant-ort01-...",
    "expiresAt": 1766530380177,
    "scopes": ["user:inference", "user:profile", "user:sessions:claude_code"],
    "subscriptionType": "max",
    "rateLimitTier": "default_claude_max_20x"
  }
}
```

### Using Token Explicitly (Advanced)

Instead of copying the file, you can set the token via environment variable:

```bash
# Extract access token
export CLAUDE_CODE_OAUTH_TOKEN=$(cat ~/.claude/oauth_token_dump.json | \
  python -c "import json,sys; print(json.load(sys.stdin)['claudeAiOauth']['accessToken'])")

# Run Claude with explicit token
CLAUDE_CODE_OAUTH_TOKEN="$CLAUDE_CODE_OAUTH_TOKEN" claude -p "test"
```

---

## Session Folder Naming

Claude creates session folders based on cwd with `/` replaced by `-`:

| cwd | Session Folder |
|-----|----------------|
| `/tmp/tests` | `-private-tmp-tests` |
| `/Users/foo/project` | `-Users-foo-project` |

This makes cleanup safe and predictable.

## Findings

Typical results show:
- **Fresh config dirs** (fewer accumulated sessions) are faster
- **~1s difference** between fastest and slowest configs
- High variance due to network latency to Anthropic API

Recommended alias for speed:
```bash
alias cc='CLAUDE_CODE_EFFORT_LEVEL=0 CLAUDE_CONFIG_DIR=/tmp/claude-sessions ~/symlinks/claude --dangerously-skip-permissions'
```