data2dsl

Ticket 002: Twin observation compatibility decision

• ID: ticket-002
• Owner: unresolved:human
• Status: DONE
• Workflow state: DONE
• Created: 2026-08-13

Goal and scope

Produce one evidence-backed compatibility decision for using the current subactor/twin Observation and EvidenceRef contracts in data2dsl. Inspect the pinned code, protobuf schema, normative standard, reference profile and tests. The result must select exactly one verdict: REUSE AS-IS, EXTEND or REJECT, and state the consequences for data2dsl.

Out of scope: product implementation, final data-query DSL, edits to subactor/twin, wellmanifest/dsl or any other repository, dependency changes, and external coordination.

Acceptance criteria

• AC-01: The decision pins the inspected subactor/twin revision.
• AC-02: Evidence covers protobuf, normative contract, validator code, reference profile and relevant tests.
• AC-03: Field-level fit and gaps for both Observation and EvidenceRef are explicit.
• AC-04: Exactly one verdict among REUSE AS-IS, EXTEND, and REJECT is selected with rationale.
• AC-05: Consequences and prohibited assumptions for data2dsl are stated.
• AC-06: No other repository is modified and the governance gate passes.

Result

The accepted decision is ADR-001: EXTEND. The Twin messages remain the preferred lineage, but deterministic typed values and reproducible evidence resolution require a separately authorized, additive contract extension before implementation.

The decision is integrated on the default branch at 6444365ea6bdb1ff0ae1ef5a850cdb497aa744c0 through GitHub PR 2.

Participants

• Human participant: unresolved; no user-* file was created by this script.
• Agent participant: ai-codex.md