Claude used /bin/sh in cron for bash-syntax script — VNM Visual scraper silently broken for days

Severity: HIGH — Silent production failure, data gap

Date discovered: 2026-04-06

What happened

Claude deployed a VNM Visual scraper cron job using /bin/sh syntax. The script used source .env — a bash-specific command that sh does not support.

When sh encountered source, it silently failed. The && chain broke. The Python script never ran. The log was never written to. The cron fired on schedule but did nothing.

The scraper had not written to its log since April 2 (4 days before discovery) despite cron running every 3 hours.

Impact

• 4+ days of VNM visual price data missing
• No alert fired (silent failure)
• Required diagnosis during a separate audit session
• Pattern: Claude deployed it, it appeared to work during manual test (because manual test used bash), but cron used sh

Why this matters

This is a trivially preventable error. Using bash -c '...' explicitly in the crontab entry is the correct approach. Claude knew the script used bash syntax. It should have written the cron with bash -c.

Requested resolution

• Refund of credits
• Fix: When writing cron entries for scripts that use bash-specific syntax, Claude must always use bash -c '...' explicitly — never rely on /bin/sh default