Running AI CLI Tools with Cron for 5-Hour Usage Windows

The Challenge

Anthropic and OpenAI enforce a 5-hour usage window - once I make my first request, I have 5 hours fixed usage before the window expires. This meant:

❌ Unpredictable availability - window could expire mid-project or at random times during the work day
❌ Frustration when usage windows expire at unopportune times
❌ Consistent work schedule and usage window planning

The Solution

I created a cron-based wrapper script that automatically activates both Claude Code and Codex on a predictable schedule (7 AM, 12 PM, 5 PM, 10 PM). Now:

✅ 5-hour windows start at predictable times throughout the day
✅ I can plan around "new usage window" consistently at 7am, 12pm, 5pm, 10pm throughout the day
✅ Logging for confirming execution/start of windows
✅ Zero manual intervention needed

This guide shares my setup so you can implement a similar approach that fits your work style.

The Wrapper Script

Create /home/code/bin/ai-cli-cron:

#!/bin/bash
# AI CLI tools wrapper for scheduled activation of usage windows
# Outputs JSON for machine-readable logs with human-friendly summaries

# ============================================================================
# CONFIGURATION - Update these values for your environment
# ============================================================================

# System paths
USER_HOME="/home/code"
NVM_DIR="$USER_HOME/.nvm"
NODE_VERSION="v22.18.0"

# Tool locations
CLAUDE_BIN="$USER_HOME/.local/bin/claude"
CODEX_BIN="$USER_HOME/.local/bin/codex"

# Timezone (see: timedatectl list-timezones)
TIMEZONE="America/Denver"

# MCP server API keys (replace with your actual keys, optional and only if seeing MCP errors)
FIRECRAWL_API_KEY="your-firecrawl-api-key-here"
OPENMEMORY_API_KEY="your-openmemory-api-key-here"

# Health check prompt
HEALTH_CHECK_PROMPT="Respond with 'Ready' if operational"

# ============================================================================
# ENVIRONMENT SETUP
# ============================================================================

export HOME="$USER_HOME"
export NVM_DIR="$NVM_DIR"
export PATH="$NVM_DIR/versions/node/$NODE_VERSION/bin:$USER_HOME/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
export TZ="$TIMEZONE"
export FIRECRAWL_API_KEY
export OPENMEMORY_API_KEY
export CLIENT_NAME="claude-code"

# ============================================================================
# LOGGING HELPER
# ============================================================================

log() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1"
}

# Parse Claude JSON response and extract key info
parse_claude_json() {
    local json="$1"
    local result=$(echo "$json" | jq -r '.result // "ERROR"')
    local duration=$(echo "$json" | jq -r '.duration_ms // 0')
    local cost=$(echo "$json" | jq -r '.total_cost_usd // 0')
    echo "result=$result, duration=${duration}ms, cost=\$${cost}"
}

# Parse Codex JSONL response and extract key info
parse_codex_jsonl() {
    local jsonl="$1"
    local last_line=$(echo "$jsonl" | tail -1)
    local type=$(echo "$last_line" | jq -r '.type // "unknown"')

    if [[ "$type" == "turn.completed" ]]; then
        local tokens=$(echo "$last_line" | jq -r '.usage.input_tokens // 0')
        echo "status=completed, tokens=${tokens}"
    elif [[ "$type" == "turn.failed" ]]; then
        echo "status=failed"
    else
        echo "status=unknown"
    fi
}

# ============================================================================
# TOOL EXECUTION
# ============================================================================

# Run Claude
log "Claude job started"
CLAUDE_OUTPUT=$("$CLAUDE_BIN" --output-format json -p "$HEALTH_CHECK_PROMPT" 2>&1)
CLAUDE_EXIT=$?
echo "$CLAUDE_OUTPUT"
log "Claude job completed (exit: $CLAUDE_EXIT) - $(parse_claude_json "$CLAUDE_OUTPUT")"
echo ""

# Run Codex
log "Codex job started"
CODEX_OUTPUT=$("$CODEX_BIN" exec --skip-git-repo-check --json "$HEALTH_CHECK_PROMPT" 2>&1)
CODEX_EXIT=$?
echo "$CODEX_OUTPUT"
log "Codex job completed (exit: $CODEX_EXIT) - $(parse_codex_jsonl "$CODEX_OUTPUT")"
echo ""

Make it executable:

chmod +x /home/code/bin/ai-cli-cron

Key Features

Organized Configuration: All customizable settings are grouped at the top:
- System paths and tool locations
- Timezone settings
- API keys
- Health check prompt
Clean Environment Setup: Cron runs with minimal environment variables. The script explicitly sets:
- PATH to include Node.js, local binaries, and system paths
- HOME, NVM_DIR for proper tool resolution
- TZ for consistent timezone handling across all timestamp operations
- MCP server API keys (optional)
JSON Output with Summaries:
- Both CLI tools output machine-readable JSON
- Claude uses --output-format json for structured response data
- Codex uses --json for JSONL (JSON Lines) event streaming
- Helper functions parse JSON and display human-friendly summaries (status, duration, cost, tokens)
Timestamp Logging: Every operation is logged with consistent timestamps in your configured timezone
Health Checks: Simple "Ready" prompts verify both tools are operational
Exit Code Tracking: Captures and logs exit codes to verify successful execution
Dependency: Requires jq for JSON parsing (install: sudo apt install jq)

Cron Setup

My Schedule (Recommended for 5-Hour Windows)

I run the script 4 times per day at 5-hour intervals to maximize coverage throughout my working hours:

0 7,12,17,22 * * * /home/code/bin/ai-cli-cron >> /home/code/logs/ai-cli-cron.log 2>&1

Schedule breakdown:

7:00 AM - Morning window (covers 7 AM - 12 PM work session)
12:00 PM - Midday window (covers 12 PM - 5 PM work session)
5:00 PM - Evening window (covers 5 PM - 10 PM work session)
10:00 PM - Late night window (covers 10 PM - 3 AM if needed)

Why this works:

Each activation starts a new 5-hour usage window
5-hour spacing ensures minimal overlap while maximizing availability
Covers typical work hours (7 AM - 10 PM) plus late night if needed
Predictable schedule - morning window > after-lunch window > evening window

Setting Up Your Cron

Edit your crontab:

crontab -e

Add the line above, adjusting times to match your work schedule. The format is:

minute hour * * * command

Tips for customizing:

Adjust times to start 30-60 minutes before you typically work
Use comma-separated hours (e.g., 7,12,17,22) for specific times
Ensure at least 5 hours between runs to establish new 5h session

Create Log Directory

mkdir -p /home/code/logs

Log Rotation (Optional)

To prevent logs from growing indefinitely, create /etc/logrotate.d/ai-cli-cron:

/home/code/logs/ai-cli-cron.log {
    daily
    rotate 7
    compress
    delaycompress
    missingok
    notifempty
}

Log Output Format

The script now outputs JSON for each tool, followed by a human-readable summary line. Example:

[2025-10-07 10:26:06] Claude job started
{"type":"result","subtype":"success","is_error":false,"duration_ms":2123,"result":"Ready","total_cost_usd":0.007160099999999999,...}
[2025-10-07 10:26:19] Claude job completed (exit: 0) - result=Ready, duration=2123ms, cost=$0.00716

[2025-10-07 10:26:19] Codex job started
{"type":"thread.started","thread_id":"0199bf7e-c1b1-7861-85b2-110c05bb9706"}
{"type":"turn.started"}
{"type":"item.completed","item":{"id":"item_0","type":"reasoning","text":"**Preparing initial response**"}}
{"type":"item.completed","item":{"id":"item_1","type":"agent_message","text":"Ready"}}
{"type":"turn.completed","usage":{"input_tokens":2937,"cached_input_tokens":2048,"output_tokens":7}}
[2025-10-07 10:26:22] Codex job completed (exit: 0) - status=completed, tokens=2937

Benefits:

JSON lines can be parsed by log analysis tools
Summary lines provide quick status at a glance
Full event data preserved for debugging

Monitoring Your Setup

With my schedule running 4 times daily (7 AM, 12 PM, 5 PM, 10 PM), you should see 8 job completions per day (4 Claude + 4 Codex).

Quick Health Check

View the most recent runs:

tail -50 /home/code/logs/ai-cli-cron.log | grep "job completed"

Expected output (shows both tools succeeded):

[2025-10-07 07:00:16] Claude job completed (exit: 0) - result=Ready, duration=2123ms, cost=$0.00716
[2025-10-07 07:00:19] Codex job completed (exit: 0) - status=completed, tokens=2937

Watch Live Execution

Monitor in real-time (useful during troubleshooting):

tail -f /home/code/logs/ai-cli-cron.log

Press Ctrl+C to exit.

Check Today's Activity

See all runs from today:

grep "$(date '+%Y-%m-%d')" /home/code/logs/ai-cli-cron.log | grep "job completed"

Verify Cron is Running

Check that your cron job is active:

# List your cron jobs
crontab -l

# Check cron service status
systemctl status cron

# View recent cron executions in system logs
grep "ai-cli-cron" /var/log/syslog | tail -20

If jobs aren't running, check:

Cron service is active: sudo systemctl start cron
Script is executable: chmod +x /home/code/bin/ai-cli-cron
Log directory exists: mkdir -p /home/code/logs

Troubleshooting

Script Doesn't Run

Check cron service: systemctl status cron
Check crontab syntax: crontab -l
Verify script permissions: ls -l /home/code/bin/ai-cli-cron
Check cron logs: grep ai-cli-cron /var/log/syslog

Environment Issues

If tools can't be found:

Verify paths in script match your installation:
```
which claude
which codex
which node
```
Update PATH variable in script accordingly

Timezone Problems

Ensure your system timezone matches the script:

timedatectl  # Check system timezone
export TZ=America/Denver  # Test in shell first

Understanding the 5-Hour Window Strategy

Some AI providers (like the one I use for Codex) enforce 5-hour usage windows where you can only make requests within a 5-hour period after your first request. This creates a problem: if you start working at unpredictable times, your usage window might expire during important work.

My solution: Run the script on a predictable schedule to pre-activate these windows at optimal times.

How My Schedule Works

By running at 7 AM, 12 PM, 5 PM, and 10 PM, I ensure:

Coverage during work hours: No matter when I start working, a window is active or will activate soon
Predictable availability: I know exactly when each 5-hour window starts and ends
No wasted activations: 5-hour spacing means each run starts a fresh window without overlap
Late-night flexibility: The 10 PM run covers unexpected late-night work sessions

Visual timeline:

7 AM activation  → covers 7 AM - 12 PM
12 PM activation → covers 12 PM - 5 PM
5 PM activation  → covers 5 PM - 10 PM
10 PM activation → covers 10 PM - 3 AM

This approach transforms an unpredictable constraint into a reliable, automated system.

Customizing for Your Setup

Before First Run

Edit the configuration section at the top of /home/code/bin/ai-cli-cron:

Verify paths:

which claude  # Should match CLAUDE_BIN
which codex   # Should match CODEX_BIN
which node    # Check Node version matches NODE_VERSION

Update these variables:
- USER_HOME - Your home directory (default: /home/code)
- NODE_VERSION - Your Node.js version (find with: node --version)
- TIMEZONE - Your timezone (list: timedatectl list-timezones)
- FIRECRAWL_API_KEY, OPENMEMORY_API_KEY - Your actual API keys
Adjust the schedule in your crontab to match your work hours:
```
crontab -e
# Change 7,12,17,22 to your preferred hours
```

Adding More Tools

To add additional AI CLI tools, insert in the "TOOL EXECUTION" section:

# Run YourTool
log "YourTool job started"
TOOL_OUTPUT=$("$YOUR_TOOL_BIN" --json "health check prompt" 2>&1)
TOOL_EXIT=$?
echo "$TOOL_OUTPUT"
log "YourTool job completed (exit: $TOOL_EXIT)"
echo ""

Optional: Email Notifications

Add to your crontab (requires mail configured):

MAILTO=[email protected]
0 7,12,17,22 * * * /home/code/bin/ai-cli-cron >> /home/code/logs/ai-cli-cron.log 2>&1

Benefits

✅ Predictable usage windows starting at optimal times

✅ Automated health checks verify tools are operational

✅ Machine-readable output - JSON/JSONL format for log analysis

✅ Human-friendly summaries - quick status overview without parsing JSON

✅ Comprehensive logging with consistent timezone-aware timestamps

✅ Cost and token tracking - automatically extracted and logged

✅ No manual intervention needed

✅ Easy to customize - all configuration at the top of the script

✅ Clean and maintainable - streamlined, professional code

✅ Multiple tools managed in one script

✅ Shareable - clearly documented configuration section

Note: Adjust paths, timezones, and schedules to match your specific setup and workflow needs.

ben-vargas/claude_codex_usage_windows.md

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