Liturgical Know-How (ePrex) in the BAIF Framework

[marcodelpin]

The Role of Liturgical Know-How in the BAIF Ecosystem

Liturgical Know-How (expertise developed from previous experience in liturgical app development) represents a concrete case of how digital liturgical experience can feed the Catholic AI infrastructure proposed by BAIF.

Note: This document describes competencies and methodologies developed during 15 years of Liturgy of the Hours app development (2010-2025). This know-how is now available to contribute to the CatholicOS/BAIF project.

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BAIF Framework: Create → Validate → Amplify

flowchart LR
    subgraph CREATE
        A[Liturgical Know-How]
        A1[BMD Format]
        A2[Validated texts]
        A3[Calendar Algo]
    end

    subgraph VALIDATE
        B[Theological Review]
        B1[Validation]
        B2[Ontology]
        B3[WebProtégé]
    end

    subgraph AMPLIFY
        C[CatholicOS APIs]
        C1[AI/LLM Layer]
        C2[RAG Pipelines]
        C3[MCP Tools]
    end

    A --> B --> C

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1. CREATE: Liturgical Know-How Contribution

1.1 Validated Liturgical Dataset

Previous experience produced a significant corpus of structured content:

Asset	Volume	Content
BMD Texts	~20MB	Complete Liturgy of the Hours (Italian)
Psalter	150 psalms	With antiphons and rubrics
Hymns	200+	All liturgical seasons
Short Readings	365+	Annual cycle
Orations	500+	Collects and prayers
Saints	365+	Proper of Saints

1.2 Structured BMD Format

The BMD (Bible MarkDown) format is a human-readable and machine-parseable markup:

##PSALM 119:145-152 XIX (Qoph) Promise to observe the law
*This is the love of God (1 Jn 5:3).*

I call with all my heart; Lord, answer me; *
    I will keep your statutes.

Automatically extracted metadata:

• ##PSALM 119:145-152 → Biblical reference
• XIX (Qoph) → Hebrew psalter section
• *...* → Related NT quotation
• * at verse end → Psalmic pause

1.3 Liturgical Calendar Algorithms

The developed algorithms cover the entire Roman calendar:

Feature	Description
Computus	Easter calculation (accurate until 2499)
Moveable feasts	Pentecost, Ascension, Corpus Christi, Trinity, etc.
Liturgical seasons	Advent, Christmas, Lent, Easter, Ordinary Time
Cycles	Three-year (A/B/C), Psalter (1-4), Biennial
Transfers	GIRM rules for feast conflicts

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2. VALIDATE: Alignment with BAIF's 9 Commitments

2.1 Truth-Seeking AI ✓

BAIF Requirement	How Know-How Fulfills It
Authoritative sources	Texts from Episcopal Conference, Vatican sources
Verifiability	BMD includes biblical references
Traceability	Documented methodology

Example of traceable citation:

{SHORT READING ^Rom 13:11-12^}
It is now the hour for you to awake from sleep...

→ The reference ^Rom 13:11-12^ is machine-readable

2.2 Transparency ✓

BAIF Requirement	Implementation
Open algorithms	Documented and reproducible logic
Readable format	BMD is human-readable
Documentation	Complete format specifications

2.3 Subsidiarity ✓

The know-how supports local adaptations for different episcopal conferences:

• Italian (CEI), Spanish, English, French, Portuguese, Arabic
• Diocesan calendars with feast transfer rules
• Local proper of saints

2.4 Human Dignity & Common Good ✓

Principles applied in previous development:

• Free: No-cost access for the faithful
• Offline: Functionality without internet
• Accessible: Simple UI for all ages
• Inclusive: Multi-language

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3. AMPLIFY: Integration with CatholicOS Stack

3.1 Data/Ontology Layer

BMD → JSON-LD conversion for Knowledge Graph:

{
  "@context": "https://catholicos.org/context/liturgy",
  "@type": "Psalm",
  "@id": "psalm:119:145-152",
  "hebrewSection": "XIX-Qoph",
  "antiphon": "My eyes anticipate the night watches...",
  "verses": [
    {
      "@type": "Verse",
      "number": 145,
      "text": "I call with all my heart; Lord, answer me",
      "pause": "flexa"
    }
  ],
  "ntReference": {
    "@type": "BibleReference",
    "book": "1John",
    "chapter": 5,
    "verse": 3
  }
}

3.2 AI/LLM Layer

Use Cases for RAG Pipeline:

User Query	Know-How Source	AI Output
"Which psalm is recited at Lauds today?"	Calendar + BMD	Correct psalm with antiphon
"What is the meaning of flexa?"	BMD_FRAGMENT_SYSTEM.md	Psalmic pause explanation
"When is Pentecost 2025?"	Calendar algorithms	2025-06-08
"Today's liturgical color?"	LiturgicalSeason	Green/Red/Violet/White

Prompt Engineering with liturgical context:

SYSTEM: You are a Catholic liturgical assistant. Use the Roman calendar
and texts from the Liturgy of the Hours. Always cite biblical references.

CONTEXT: {BMD content for today}

USER: What do we celebrate today?

ASSISTANT: Today is [liturgical date] of [Ordinary Time/etc].
The Lauds psalm is [X], with the antiphon "[antiphon]".
The short reading is from [reference]: "[text]"

3.3 Runtime/MCP Layer

MCP Tools based on Liturgical Know-How:

// Tool: get_liturgical_day
{
  name: "get_liturgical_day",
  description: "Gets information about the liturgical day",
  parameters: {
    date: { type: "string", format: "date" }
  },
  returns: {
    season: "Liturgical season",
    week: "Psalter week (1-4)",
    cycle: "Liturgical year (A/B/C)",
    celebrations: "List of celebrations"
  }
}

// Tool: get_hour_text
{
  name: "get_hour_text",
  description: "Gets the text of a liturgical hour",
  parameters: {
    date: { type: "string", format: "date" },
    hour: { enum: ["OOR", "LAU", "TER", "SEX", "NON", "VES", "COM"] }
  }
}

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4. Liturgical Knowledge Graph

4.1 WebProtégé Ontology

@prefix cath: <https://catholicos.org/ontology/> .
@prefix lkh: <https://catholicos.org/liturgical-knowhow/> .

# Psalm class with metadata
cath:Psalm a owl:Class ;
    rdfs:subClassOf cath:BiblicalText ;
    owl:equivalentClass [
        a owl:Restriction ;
        owl:onProperty cath:hasHebrewSection ;
        owl:someValuesFrom cath:HebrewPsalterSection
    ] .

# Example instance
lkh:psalm119 a cath:Psalm ;
    cath:psalmNumber 119 ;
    cath:hasSection lkh:psalm119_145_152 ;
    cath:hebrewSection cath:Qoph .

lkh:psalm119_145_152 a cath:PsalmSection ;
    cath:verseRange "145-152" ;
    cath:hasAntiphon "My eyes anticipate the night watches..." ;
    cath:ntCrossReference <urn:bible:1john:5:3> .

4.2 LinkML Schema

id: https://catholicos.org/schemas/liturgy-hours
name: liturgy_hours
prefixes:
  lkh: https://catholicos.org/liturgical-knowhow/

classes:
  HourOfOffice:
    attributes:
      type:
        range: HourType
        required: true
      invitatory:
        range: Invitatory
      hymn:
        range: Hymn
      psalmody:
        range: Psalmody
      reading:
        range: Reading
      canticle:
        range: GospelCanticle
      prayer:
        range: CollectPrayer

enums:
  HourType:
    permissible_values:
      OFFICE_OF_READINGS: { meaning: lkh:OOR }
      LAUDS: { meaning: lkh:LAU }
      TERCE: { meaning: lkh:TER }
      SEXT: { meaning: lkh:SEX }
      NONE: { meaning: lkh:NON }
      VESPERS: { meaning: lkh:VES }
      COMPLINE: { meaning: lkh:COM }

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5. Strategic Value for BAIF

5.1 Unique Assets from Liturgical Know-How

Asset	Value	Uniqueness
15 years of experience	Tested methodologies	Rare
Validated content	Clean dataset	Unique
Calendar algorithms	Reference impl.	Critical
Multi-language	6+ languages	Scalable
User experience	Real feedback	Valuable

5.2 Contribution to Working Groups

flowchart TB
    subgraph INPUT["Input Working Groups"]
        LC["Liturgical Calendar<br/>✓ Algorithms<br/>✓ Moveable feasts"]
        SC["Scripture<br/>✓ Bible refs<br/>✓ Cross-refs"]
    end

    subgraph CORE["Liturgical Know-How"]
        LKH["• BMD Format<br/>• Dataset<br/>• 15yr Exp."]
    end

    subgraph OUTPUT["Output Working Groups"]
        SM["Saints & Martyrology<br/>✓ Saint DB<br/>✓ Feast days"]
        LH["Liturgy of the Hours<br/>✓ All 7 hours<br/>✓ Rubrics"]
    end

    LC --> LKH
    SC --> LKH
    LKH --> SM
    LKH --> LH

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6. Conclusion

Liturgical Know-How brings to BAIF:

1. Real Implementation: Not theory, but production-tested methodologies
2. Validated Dataset: Content already ecclesiastically approved
3. 15 Years of Experience: Problems solved, edge cases handled
4. Multi-platform: iOS, Android, Windows Phone, .NET MAUI experience
5. User Feedback: Years of interaction with real users

Proposal: Contribute Liturgical Know-How as the foundation for the "Liturgy of the Hours" Working Group in the CatholicOS PMC.

[JohnRDOrazio]

This is great! As a project for the All Saints Hackathon, @RandyDanielson and myself put together an MCP that can query the liturgical calendar API: https://github.com/CatholicOS/liturgical-calendar-mcp. I don't yet have any of the texts of the lectionary readings in the API, I'm only starting to add the biblical references. We can join some of our efforts to produce a truly valuable API!

[matthewa26]

We'll just have to add more liturgical references then. Christmas through Ash Wednesday 2026 is the next chunk that I plan to contribute as soon as today, in the English translation.

[JohnRDOrazio]

@matthewa26 thank you for your precious contributions!