ISO Week Number

com.gumballtools/iso-weekVersion 0.1.0

ISO 8601 week numbers: date to week, week to date, weeks-per-year.

Status

Responds904 msNov 14, 2026, 14:00 UTCAnswered our handshake without sign-in.

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Last checked: Nov 14, 2026, 14:00 UTC
Latency: 904 ms
Remotes responding: 1 of 1
Sign-in: No sign-in
Hosting: Hosted outside the EU (detected)
Registry data as of: Nov 14, 2026, 22:14 UTC

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Connect

Streamable HTTP

https://iso-week.gumballtools.com/api/mcpResponds904 msNov 14, 2026, 14:00 UTC

No sign-in

Claude Code

claude mcp add --transport http iso-week https://iso-week.gumballtools.com/api/mcp

Claude Desktop and claude.ai

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Settings > Connectors > Add custom connector
Name: iso-week
Remote MCP server URL: https://iso-week.gumballtools.com/api/mcp

Cursor

{
  "mcpServers": {
    "iso-week": {
      "url": "https://iso-week.gumballtools.com/api/mcp"
    }
  }
}

VS Code

code --add-mcp '{"name":"iso-week","type":"http","url":"https://iso-week.gumballtools.com/api/mcp"}'

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Tools

1 tools

Tools of ISO Week Number
	Description		Read-only	Idempotent	Open world
`run`Converts between calendar dates and ISO 8601 week numbers, in either direction, and reports how many weeks an ISO year has. Use this whenever a date needs to be expressed as a week number, or a week number needs to be turned back into a date — sprint planning, report periods, "week 37" style scheduling, or reconciling two systems that disagree about what week it is. DO NOT compute this yourself with day-of-year divided by 7. ISO 8601 week 1 is defined as the week (Monday-Sunday) containing the year's first Thursday, not the week containing January 1st. This has two consequences that are easy to get wrong from memory: late-December dates can belong to ISO week 1 of the NEXT calendar year, and early-January dates can belong to ISO week 52 or 53 of the PREVIOUS calendar year. A year has 53 ISO weeks (not the usual 52) exactly when January 1 is a Thursday, or the year is a leap year and January 1 is a Wednesday — a rule nobody carries around, and getting it wrong produces a plausible-looking but incorrect week number with no visible sign of the error. Input is a single string, and the shape of the string picks the operation: "2027-01-01" a calendar date (YYYY-MM-DD) -> returns its ISO year, week, and weekday "2026-W53" an ISO week, no weekday given -> returns the Monday of that week "2026-W53-5" an ISO week and weekday (1-7, Mon-Sun) -> returns that exact date "2026" a bare 4-digit year -> returns whether it has 52 or 53 ISO weeks Refuses rather than guesses: slash-separated dates like "03/04/2025" are rejected as ambiguous (month/day vs day/month), two-digit years are rejected as a guess, invalid calendar dates (Feb 30) are rejected, and a week number beyond what that ISO year actually has (e.g. week 53 of a 52-week year) is rejected and told how many weeks that year has.	Converts between calendar dates and ISO 8601 week numbers, in either direction, and reports how many weeks an ISO year has. Use this whenever a date needs to be expressed as a week number, or a week number needs to be turned back into a date — sprint planning, report periods, "week 37" style scheduling, or reconciling two systems that disagree about what week it is. DO NOT compute this yourself with day-of-year divided by 7. ISO 8601 week 1 is defined as the week (Monday-Sunday) containing the year's first Thursday, not the week containing January 1st. This has two consequences that are easy to get wrong from memory: late-December dates can belong to ISO week 1 of the NEXT calendar year, and early-January dates can belong to ISO week 52 or 53 of the PREVIOUS calendar year. A year has 53 ISO weeks (not the usual 52) exactly when January 1 is a Thursday, or the year is a leap year and January 1 is a Wednesday — a rule nobody carries around, and getting it wrong produces a plausible-looking but incorrect week number with no visible sign of the error. Input is a single string, and the shape of the string picks the operation: "2027-01-01" a calendar date (YYYY-MM-DD) -> returns its ISO year, week, and weekday "2026-W53" an ISO week, no weekday given -> returns the Monday of that week "2026-W53-5" an ISO week and weekday (1-7, Mon-Sun) -> returns that exact date "2026" a bare 4-digit year -> returns whether it has 52 or 53 ISO weeks Refuses rather than guesses: slash-separated dates like "03/04/2025" are rejected as ambiguous (month/day vs day/month), two-digit years are rejected as a guess, invalid calendar dates (Feb 30) are rejected, and a week number beyond what that ISO year actually has (e.g. week 53 of a 52-week year) is rejected and told how many weeks that year has.	Not declared	Yes	Not declared	No

Details

Registry status: Active
Published: Sep 6, 2026
Updated: Sep 6, 2026
Website: https://iso-week.gumballtools.com/⁠ (opens in a new tab)
Repository: https://github.com/bwalvoord/gumball⁠ (opens in a new tab)
Categories: Uncategorized
GDPR: Not declared

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