Module schema 

Schema Registry & Ontology

Persistent, versioned database schemas for every AI chat provider and format version, plus an ontology layer that makes schemas discoverable by AI agents.

Architecture

┌─────────────────────────────────────────────────────────────┐
│                    Schema Registry                          │
│  ┌─────────────┐ ┌────────────-─┐ ┌─────────────┐           │
│  │  Copilot v3 │ │ Copilot JSONL│ │  Cursor v1  │  ...      │
│  │  (JSON)     │ │  (0.37+)     │ │             │           │
│  └─────────────┘ └──────────────┘ └─────────────┘           │
├─────────────────────────────────────────────────────────────┤
│                    Ontology Layer                           │
│  • Entity types, relationships, field semantics             │
│  • Cross-provider mappings (field A in X ≡ field B in Y)    │
│  • Version migration paths                                  │
│  • Machine-readable capability descriptors                  │
└─────────────────────────────────────────────────────────────┘

Usage

use csm::schema::{SchemaRegistry, SchemaVersion};

let registry = SchemaRegistry::new();

// List all known schemas
for schema in registry.list_schemas() {
    println!("{}: {} fields", schema.id(), schema.field_count());
}

// Detect schema for a workspace
let detected = registry.detect_schema("/path/to/workspace")?;

// Query the ontology
let ontology = registry.ontology();
let mappings = ontology.cross_provider_mappings("copilot-jsonl-v1", "cursor-v1");

Structs

CrossProviderMapping

A mapping between fields in two different provider schemas.

DbKeySchema

Schema for a key in a SQLite key-value store (like VS Code’s state.vscdb)

DetectedSchema

Result of schema auto-detection

EntityRelationship

A relationship between two entity types

FieldSchema

Schema for a single field in a session record

MigrationPath

Describes how to migrate data from one schema version to another.

Ontology

The complete ontology over all provider schemas.

ProviderSchema

Complete schema definition for one provider at one version.

SchemaRegistry

Central registry of all known AI chat provider schemas.

SchemaVersion

Unique identifier for a provider schema version.

SemanticTag

A semantic tag represents a universal concept that may appear under different field names in different providers.

SessionFormatSchema

Schema for the session file/record format

StorageLocation

Platform-aware storage location descriptor

Enums

DataType

Supported data types

EntityType

High-level entity types that appear across providers

FieldConstraint

Constraints on field values

FieldTransform

Transformation to apply when mapping a field between providers

FormatType

Session file format

RelationshipKind

Kinds of relationships between entities

StorageType

Where session data is stored

Functions

build_all_provider_schemas

Build and return all known provider schemas.

claude_code_v1

Claude Code CLI session schema.

codex_cli_v1

OpenAI Codex CLI session schema.

continue_dev_v1

Continue.dev VS Code extension session schema.

copilot_json_v3

VS Code Copilot Chat JSON format (extensions 0.25.0 – 0.36.99).

copilot_jsonl_v1

VS Code Copilot Chat JSONL event-sourced format (extensions 0.37.0+).

cursor_v1

Cursor IDE chat session schema.

gemini_cli_v1

Google Gemini CLI session schema.

openai_api_v1

Generic OpenAI API-compatible conversation format.