JMoak Chrono MCP

What JMoak-chrono-mcp MCP server does

JMoak-chrono-mcp MCP server exposes time operations for MCP-compatible AI clients. It can obtain the current time, convert a datetime among IANA timezones, and format results as ISO, RFC 2822, SQL, localized, or locale-aware short-to-full representations. Formatting can include UTC offsets and a selected locale such as en-US, fr-FR, or ja-JP.

The calculation tool supports adding and subtracting durations, finding differences in selected units, and producing a detailed duration breakdown between two datetimes. It can also sort timestamps, calculate aggregate statistics for timestamp series and durations, and expand recurring schedules into concrete occurrences.

How it works

Inputs use ISO datetime strings and may identify separate timezones for the base and comparison values. Operations can receive individual values or arrays. An interaction mode controls whether arrays are processed pairwise, as a cross-product, or through single-to-many, many-to-single, or aggregate handling. Invalid entries in batch requests are reported rather than silently removed.

Recurrence expansion accepts RFC 5545 RRULE expressions and ISO 8601 repeating intervals. Optional time windows and occurrence limits constrain the result, while the response indicates whether expansion was truncated. The implementation is powered by Luxon and is designed to account for daylight-saving transitions when recurring wall-clock times cross a timezone change.

The server also adds a compact temporal context line to tool responses. It reports the current time, weekday, elapsed time since the previous agent call when available, session age, and timezone database version.

Setup and configuration

For a local stdio-style launch, run:

npx @jmoak/chrono-mcp

A local HTTP deployment can be built and started with:

npm install
npm run build
npm run start:http

The HTTP endpoint is available at http://localhost:8000/mcp, with a health check at /health. The README shows MCP configuration examples for Claude Code and Cursor using either the npx command or the local HTTP URL.

Tools and capabilities

JMoak-chrono-mcp MCP server provides these calculation operations:

• add and subtract for duration arithmetic.
• diff for differences in selected units.
• duration_between for a component-based duration breakdown.
• stats for timestamp and interval aggregates, supporting up to 100,000 timestamps per call.
• sort for chronological ordering.
• expand for RRULE and ISO repeating-interval expansion.

Per-item operations support batches of up to 10,000 values. Results can use RFC 9557 IXDTF-style bracketed IANA zone annotations, including offset-consistency validation and ixdtf output. Inputs are validated with Zod and errors follow MCP handling conventions.

Limitations and notes

The documented occurrence cap for expand defaults to 100 and can be raised to 10,000. Large statistics requests return aggregates rather than every derived result. The server requires a Node.js environment capable of running the published npm package; the supplied material does not specify environment variables or additional service credentials.