About Cron Schedule Audit
Cron Schedule Audit is an MCP server for developers validating cron schedules and checking daylight-saving-time risks. It validates schedule semantics and calculates next runs using IANA timezone data, flagging skipped or repeated times.
Key features
- 01Cron syntax and semantic validation
- 02DST-aware next-fire calculations
- 03Skipped and repeated time detection
- 04Year-ahead DST risk scanning
Use cases
- 01Validate a cron schedule before deployment
- 02Check jobs scheduled during DST transitions
- 03Find day-of-month and day-of-week OR behavior
MCP support
Exposes cron validation, next-fire calculation, and DST risk detection tools to MCP clients.
Configuration
Remote servers need no local install. Pick your client, then copy the config or install in one click.
https://cron-schedule-audit-mcp.mcpize.run/mcpclaude mcp add --transport http tylerscomic-lab-cron-schedule-audit https://cron-schedule-audit-mcp.mcpize.run/mcp{"mcpServers":{"tylerscomic-lab-cron-schedule-audit":{"type":"http","url":"https://cron-schedule-audit-mcp.mcpize.run/mcp"}}}Open in Cursor{"servers":{"tylerscomic-lab-cron-schedule-audit":{"type":"http","url":"https://cron-schedule-audit-mcp.mcpize.run/mcp"}}}Open in VS Code{"mcpServers":{"tylerscomic-lab-cron-schedule-audit":{"type":"http","url":"https://cron-schedule-audit-mcp.mcpize.run/mcp"}}}{"mcpServers":{"tylerscomic-lab-cron-schedule-audit":{"serverUrl":"https://cron-schedule-audit-mcp.mcpize.run/mcp"}}}Run commands in a terminal; paste JSON into the client’s MCP config and restart. Servers that need sign-in will prompt on first connect.
Tools
Details
From the project READMEcron-schedule-audit-mcp
An MCP server that validates cron expressions and computes DST-correct next-fire times using the real IANA
timezone database — no moment-timezone or luxon dependency, just a hand-rolled fake-UTC-offset technique
against the platform's own tz data.
The bug this catches
A cron job scheduled at 30 2 * * * (2:30am daily) in America/New_York silently never fires on the
spring-forward date, because 2:00-2:59am doesn't exist that day. A job at 30 1 * * * (1:30am) fires twice on
the fall-back date, because that hour is repeated. Neither failure throws an error or shows up in logs — it just
looks like a flaky cron that "sometimes doesn't run." Verified against real 2026/2027 transition dates during
testing (spring-forward 2027-03-14, fall-back 2026-11-01).
Also flags the day-of-month/day-of-week footgun almost everyone hits once: POSIX cron treats both fields as OR, not AND, when both are restricted.
Tools
validate_cron_expression
Syntax + semantic validation: OR-not-AND warning, every-minute footgun, day-of-month values some months don't have (31, 30, 29), a nudge to check DST risk for anything in the 1-3am window. Returns a plain-English explanation of what the expression means.
get_next_fire_times
Next N fire times, DST-aware. If a scheduled local time falls in a spring-forward gap it's flagged as skipped; if it falls in a fall-back overlap, both real firings are returned as ambiguous.
detect_dst_risk
Scans a full year ahead and reports every date where the schedule collides with a DST transition — run this once on any job scheduled in the 1-4am local window before you ship it.
Use it
Hosted (recommended): MCPize — free tier, $7/mo Pro.
Self-host:
npm install
node server.js
Part of a small suite
mcp-schema-audit-mcp, regex-safety-audit-mcp, claude-cost-audit-mcp.
License
MIT
Comments
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