Fetch, compute, and format religious observance calendars for the three in-scope Abrahamic traditions of the Abrahamic Reference Engine: Judaism, Christianity, and Islam.
SkillScore82Maintained
Automatic
◆Coding pack
Last verified 8/4/2026
What it changes
Passed 18 of 22 test cases with the skill, and 7 of 22 without it.
Without skill32%
With skill82%
Checks it passed that the model alone missed
Includes a boolean isMultiDay flag
Assigns the Orthodox Cross emoji to Orthodox events
Sets the isMultiDay flag to true for grouped events
and 14 more in the full report
11 fixed7 passed either way4 still failing0 broke
Pass-rate lift
+50 pp
Tokens
+136%
Agent turns
0%
Response time
-36%
Model gemini-3.6-flashMeasured 8/4/2026v118 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 11 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 11
Prompt
What are the required attribution texts and licenses for the Jewish, Islamic, and Wikipedia data sources?
What was checked, without and with the skill
Checked
Without skill
With skill
Requires the CC BY 4.0 license for the Jewish source
Passed
Passed
Requires the CC BY-SA 3.0 license for the Wikipedia source
Missed
Passed
case-17 · gemini-3.6-flash · 8/4/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
Fetch, compute, and format religious observance calendars for the Abrahamic Reference Engine.
Covers Judaism (Hebcal API), Christianity (Computus algorithm -- Western and Orthodox), and Islam (AlAdhan API). All sources are free and anonymous. No API key. No cost. Zero runtime dependencies beyond fetch.
Execution contract
Accept a target year and optional tradition or denomination filter. Validate
the year before constructing provider URLs or date objects.
Normalize every source into ObservanceEvent and retain the source,
attribution, and caveat fields. Computed dates, provider dates, and missing
dates must remain distinguishable.
Use Promise.allSettled for independent provider or month requests so one
outage does not discard successful results. Surface partial failure in the UI
or return metadata rather than hiding it.
Do not replace the deterministic Christian Computus path with a paid,
credentialed, or unverified holiday API. Run the bundled Easter validator
after algorithm changes.
Treat Islamic dates as calendar estimates. State the local moon-sighting
caveat, and never present an estimated date as universally authoritative.
Fetch Wikipedia descriptions lazily, cache only non-sensitive results, and
display the exact attribution string with the returned article URL.
Escape user- or provider-derived values before inserting them into .ics.
Follow the bundled RFC 5545 line-folding and date rules.
Bundled reference files
Read these on demand -- only the file(s) you actually need for the current task:
File
When to read
references/api-reference.md
Full API schemas and field details for Hebcal and AlAdhan; use when you need the complete response shape or want to understand all available query parameters
references/computus.md
Computus algorithm derivation, edge cases, century correction, and multi-century validation dates; use when troubleshooting Easter date accuracy
references/holiday-data.md
Extended WIKIPEDIA_ARTICLE_MAP entries and supplementary AlAdhan display name notes; use when adding a holiday not covered by the map in this file
references/ics-spec.md
ICS format specification, RFC 5545 line-folding rules, calendar client compatibility notes, and VTIMEZONE considerations