cleveragents-core/docs/reference/temporal_data_model.md

Temporal Data Model (Revision-Aware RDF)

The Temporal Data Model enables revision tracking of UKO knowledge graph nodes across three storage tiers (hot/warm/cold). When code changes, existing nodes are not deleted -- they are marked historical and a new revision node is created with a back-link to the predecessor.

Based on docs/specification.md lines 41940--42499.

Architecture

Code Change ──► Analyzer ──► TemporalService.create_revision()
                                    │
                         ┌──────────┴───────────┐
                         │  TemporalBackend     │
                         │  ┌─────────────────┐ │
                         │  │ Old node:       │ │
                         │  │  isCurrent=false│ │
                         │  │  validUntil=now │ │
                         │  ├─────────────────┤ │
                         │  │ New node:       │ │
                         │  │  isCurrent=true │ │
                         │  │  isRevisionOf=  │ │
                         │  │    old_uri      │ │
                         │  └─────────────────┘ │
                         └──────────────────────┘

Domain Models

All models are frozen Pydantic BaseModel instances (immutable value objects).

TemporalMetadata

Temporal fields carried by every UKO InformationUnit. Maps to the OWL temporal properties defined in UKO Layer 0.

Field	Type	Default	Spec Property
valid_from	datetime (UTC)	required	uko:validFrom
valid_until	datetime | None	None	uko:validUntil
is_current	bool	True	uko:isCurrent
is_revision_of	str | None	None	uko:isRevisionOf

TemporalNode

A UKO InformationUnit with full temporal metadata and provenance.

Field	Type	Default	Description
node_uri	str	required	Unique UKO URI (e.g., uko-py:class/Auth_v2)
source_resource	str	required	ULID of originating resource
source_path	str	required	File path within the resource
source_range	str | None	None	Source range (e.g., "15:1-87:0")
temporal	TemporalMetadata	required	Embedded temporal metadata

RevisionChain

Ordered chain of node versions for a single UKO concept.

Field	Type	Default	Description
current_uri	str	required	URI of the current head node
predecessors	tuple[str, ...]	()	Predecessor URIs (oldest-first)

Properties: depth (total versions), all_uris (predecessors + current).

TierRetentionConfig

Retention policy for warm and cold tiers.

Field	Type	Default	Config Key
warm_retention_hours	int (≥1)	24	context.tiers.warm.retention-hours
cold_retention_days	int (≥1)	90	context.tiers.cold.retention-days

TierQueryResult

Result from a tier-aware temporal query.

Field	Type	Default	Description
nodes	tuple[TemporalNode, ...]	()	Matching nodes
tier	ContextTier	required	HOT / WARM / COLD
temporal_scope	TemporalScope	required	CURRENT / RECENT / ALL

TemporalBackend Protocol

class TemporalBackend(Protocol):
    def store_node(self, node) -> None: ...
    def create_revision(self, current_uri, new_node, timestamp) -> TemporalNode: ...
    def get_current(self, node_uri_base) -> TemporalNode | None: ...
    def get_history(self, node_uri_base, temporal_scope) -> tuple[TemporalNode, ...]: ...
    def get_revision_chain(self, node_uri) -> RevisionChain: ...
    def query_by_tier(self, tier, temporal_scope, retention) -> TierQueryResult: ...
    def mark_historical(self, node_uri, timestamp) -> TemporalNode: ...

Three Storage Tiers

Tier	Content	Temporal Filter	Retention
Hot	Current UKO graph	isCurrent = true only	Until removed
Warm	Recent context	Current + recently-expired	warm_retention_hours (24h)
Cold	All historical	All temporal versions	cold_retention_days (90d)

Revision Chain Mechanics

1. Old node: is_current → False, valid_until → timestamp
2. New node: is_current → True, valid_from → timestamp
3. New node: is_revision_of → old node URI
4. Old node's valid_from is preserved unchanged

v1 Limitations

• InMemoryTemporalBackend stores all nodes in a dict; no persistence.
• No SPARQL query helpers yet (deferred to graph backend integration).
• temporal-archaeology strategy stub exists but does not yet use the temporal backend (wiring deferred to strategy integration milestone).