Domain Model

This document describes all domain entities in paladin-ai-core and the Medieval Military naming convention that provides Paladin's ubiquitous language.

Medieval Military Naming Convention

Paladin applies Domain-Driven Design's ubiquitous language principle through a consistent Medieval Military theme. Use these terms in all code, documentation, and discussions:

Node Pattern

All domain entities use the Node<T> wrapper which adds identifier, timestamps, and metadata to any data payload:

// crates/paladin-core/src/base/node.rs
pub struct Node<T> {
    pub id:         Uuid,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
    pub node:       T,         // The domain payload
}

Domain types are type aliases:

// crates/paladin-core/src/platform/container/paladin.rs
pub type Paladin = Node<PaladinData>;

Core Domain Entities

Paladin (Aggregate Root)

// PaladinData — the domain payload inside Node<PaladinData>
pub struct PaladinData {
    pub name:          String,
    pub system_prompt: String,
    pub model:         String,
    pub temperature:   f32,
    pub max_loops:     u32,
    pub stop_words:    Vec<String>,
    pub status:        PaladinStatus,
}

pub enum PaladinStatus {
    Idle,
    Running,
    Completed,
    Failed,
    Timeout,
}

pub type Paladin = Node<PaladinData>;

Invariants:

• system_prompt must not be empty
• temperature must be in 0.0..=2.0
• max_loops must be >= 1

Garrison (Memory Domain)

// crates/paladin-core/src/platform/container/garrison.rs
pub struct GarrisonEntry {
    pub role:       MessageRole,   // User | Assistant | System | Tool
    pub content:    String,
    pub token_count: usize,
    pub metadata:   HashMap<String, Value>,
}

Adapters: InMemoryGarrison, SqliteGarrison (feature sqlite) — see Garrison Memory.

Arsenal (Tool Domain)

// crates/paladin-core/src/platform/container/arsenal/
pub struct ToolDefinition {
    pub name:        String,
    pub description: String,
    pub parameters:  serde_json::Value,  // JSON Schema
}

pub struct ToolCall {
    pub id:        String,
    pub tool_name: String,
    pub arguments: serde_json::Value,
}

pub struct ToolResult {
    pub tool_call_id: String,
    pub content:      String,
    pub is_error:     bool,
}

Citadel (State Persistence)

// crates/paladin-core/src/platform/container/citadel.rs
pub struct CitadelEntry {
    pub paladin_name: String,
    pub state:        PaladinState,
    pub saved_at:     DateTime<Utc>,
}

Herald (Output Formatting)

// crates/paladin-core/src/platform/container/herald.rs
pub trait Herald: Send + Sync {
    fn format(&self, result: &PaladinResult, paladin: &Paladin) -> Result<String, HeraldError>;
}

Implementations: JsonHerald, MarkdownHerald, TableHerald — see Herald Output.

Base Primitives (crates/paladin-core/src/base/)

Error Types

Each domain has a dedicated error enum using thiserror:

See Design Patterns for the error handling convention.

Bounded Contexts

See Also

• Architecture Overview
• Hexagonal Design
• Crate Map
• Design Patterns — PaladinBuilder and error conventions