Markdown and Gherkin twins derive equal graphs and contracts

outcome

Prove the Gherkin carrier derives the same graph and generated contract semantics as its Markdown twin.

Examples

Given the Gherkin fixture corpus {probe: "parity"}
When the fixture corpus is extracted and validated
Then extraction reports {findingCount: 0} findings
Then the graph for {parityLeft: "twin.sdp.md"} equals the graph for {parityRight: "twin.sdp.gherkin"}
Then the contracts for {parityLeft: "twin.sdp.md"} equal the contracts for {parityRight: "twin.sdp.gherkin"}

Verifier bindings

• test:protocol.gherkin-authoring.contract-parity · the contract-parity point verifies the Gherkin carrier contract · anchored · test anchor binding present · test/self-hosting-carrier-gherkin.test.ts:388

  External run evidence from test/self-hosting-carrier-gherkin.test.ts

  Test anchors: test:protocol.gherkin-authoring.authored-fact-refused, test:protocol.gherkin-authoring.contract-parity, test:protocol.gherkin-authoring.description-location-refused, test:protocol.gherkin-authoring.duplicate-surface-refused, test:protocol.gherkin-authoring.example-space-extraction, test:protocol.gherkin-authoring.malformed-relation-refused, test:protocol.gherkin-authoring.missing-id-refused, test:protocol.gherkin-authoring.multi-finding-bounded, test:protocol.gherkin-authoring.parent-child-extraction, test:protocol.gherkin-authoring.step-less-scenario-refused, test:protocol.gherkin-authoring.unbound-ready-refused, test:protocol.gherkin-authoring.unknown-tag-refused, test:protocol.gherkin-authoring.unsupported-construct-refused. Specs verified by those bindings: spec:carrier.gherkin-authoring, spec:carrier.gherkin-authoring.authored-fact-refused, spec:carrier.gherkin-authoring.contract-parity, spec:carrier.gherkin-authoring.description-location-refused, spec:carrier.gherkin-authoring.duplicate-surface-refused, spec:carrier.gherkin-authoring.example-space-extraction, spec:carrier.gherkin-authoring.malformed-relation-refused, spec:carrier.gherkin-authoring.missing-id-refused, spec:carrier.gherkin-authoring.multi-finding-bounded, spec:carrier.gherkin-authoring.parent-child-extraction, spec:carrier.gherkin-authoring.step-less-scenario-refused, spec:carrier.gherkin-authoring.unbound-ready-refused, spec:carrier.gherkin-authoring.unknown-tag-refused, spec:carrier.gherkin-authoring.unsupported-construct-refused, spec:validation.kind-evidence.

  Run 1: external run evidence from vitest 4.1.10

  Build: CI 380 · Branch: feature/roadmap-and-slices-v0 · Commit: 34909918bf0be0e849959644401797191cae379f · Start: 2026-10-22T17:40:31.456Z · Stop: 2026-10-22T17:42:16.171Z

  Name	Suite	Result	Duration
  executes the bound example against a fresh world	An authored delivery fact lookalike is refused (spec:carrier.gherkin-authoring.authored-fact-refused)	passed	8.77 ms
  executes the bound example against a fresh world	Markdown and Gherkin twins derive equal graphs and contracts (spec:carrier.gherkin-authoring.contract-parity)	passed	25.13 ms
  executes the bound example against a fresh world	Duplicate Markdown and Gherkin surfaces are both excluded (spec:carrier.gherkin-authoring.duplicate-surface-refused)	passed	2.76 ms
  executes the bound example against a fresh world	The pseudo-scenario supplies example space without a node (spec:carrier.gherkin-authoring.example-space-extraction)	passed	1.66 ms
  executes the bound example against a fresh world	A malformed relation target is refused (spec:carrier.gherkin-authoring.malformed-relation-refused)	passed	1.32 ms
  executes the bound example against a fresh world	A Feature without identity is refused (spec:carrier.gherkin-authoring.missing-id-refused)	passed	1.16 ms
  executes the bound example against a fresh world	A Feature and Scenario enter the graph as parent and child (spec:carrier.gherkin-authoring.parent-child-extraction)	passed	1.84 ms
  executes the bound example against a fresh world	A Gherkin example with an unbound used slot fails its stated readiness floor (spec:carrier.gherkin-authoring.unbound-ready-refused)	passed	5.39 ms
  executes the bound example against a fresh world	A graph-aware tag near miss is refused (spec:carrier.gherkin-authoring.unknown-tag-refused)	passed	2 ms
  executes the bound example against a fresh world	A Scenario Outline is refused (spec:carrier.gherkin-authoring.unsupported-construct-refused)	passed	1.89 ms
  executes the bound example against a fresh world	A bad description key reports its physical source line (spec:carrier.gherkin-authoring.description-location-refused)	passed	1.28 ms
  executes the bound example against a fresh world	A step-less Scenario is refused at its Scenario line (spec:carrier.gherkin-authoring.step-less-scenario-refused)	passed	1.05 ms
  executes the bound example against a fresh world	Multiple findings exclude one carrier and keep a healthy sibling (spec:carrier.gherkin-authoring.multi-finding-bounded)	passed	2.56 ms

Requirement drawing

• Satisfying or referencing units: no recorded binding.

Decisions

No decision record named.

No implementation neighborhood recorded.

Runtime observation: not tracked.

Runtime observation: not tracked.

Build attestations: not tracked.

Deployments: not tracked.

Bills of materials: not tracked.