llm.diff — Prompt/Response Delta
Auto-documented module:
spanforge.namespaces.diff
The llm.diff.* namespace records computed differences between two events,
allowing regression detection and prompt-drift analysis (RFC-0001 §6).
Payload classes
| Class | Event type | Description |
|---|---|---|
DiffComputedPayload | llm.diff.computed | A diff was computed between two events |
DiffRegressionFlaggedPayload | llm.diff.regression.flagged | A diff exceeded a regression threshold |
DiffComputedPayload — key fields
| Field | Type | Required | Description |
|---|---|---|---|
ref_event_id | str | ✓ | ULID of the reference (baseline) event |
target_event_id | str | ✓ | ULID of the target event being compared |
diff_type | str | ✓ | One of "prompt", "response", "template", "token_usage", "cost" |
similarity_score | float | ✓ | Semantic similarity in [0.0, 1.0] |
added_tokens | int | None | — | Tokens added relative to the reference |
removed_tokens | int | None | — | Tokens removed relative to the reference |
diff_algorithm | str | None | — | Algorithm used. One of "embedding_cosine", "levenshtein", "token_edit", "lcs", "semantic_embedding" |
ref_content_hash | str | None | — | SHA-256 of the reference content |
target_content_hash | str | None | — | SHA-256 of the target content |
computation_duration_ms | float | None | — | Diff computation latency |
Example
from spanforge import Event, EventType
from spanforge.namespaces.diff import DiffComputedPayload
payload = DiffComputedPayload(
ref_event_id="01HXABC0000000000000000000",
target_event_id="01HXDEF0000000000000000000",
diff_type="prompt",
similarity_score=0.92,
added_tokens=15,
removed_tokens=8,
diff_algorithm="embedding_cosine",
)
event = Event(
event_type=EventType.DIFF_COMPUTED,
source="my-app@1.0.0",
org_id="org_01HX",
payload=payload.to_dict(),
)
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