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Open standard

VLS: a vendor-neutral verification artifact spec

VLS is a vendor-neutral wire format for verification artifacts produced by AI coding agents and verification tools.

Verification Layer SpecificationJSON Schema 2020-12reference impl: Timaeus
taskscore.jsonBLOCK
case
checkout-promo-code
claim
“Promo codes now apply at checkout.”
confidence0.94
acceptance gates3/4 passed
  • apply-valid-code
  • reject-expired-code
  • stack-with-sale-price
  • ui-shows-discount-line
What it specifies

Four pieces

TaskScore artifact

A calibrated, per-case verdict referencing the task, acceptance results, and evidence.

JSON Schema 2020-12

Artifacts validate against published schemas, so any tool can produce or consume them.

Conformance corpus

A shared set of fixtures an implementation must satisfy to claim conformance.

Reference implementation

Timaeus in TypeScript, with room for a second independent implementation.

Artifact shape

A TaskScore is just data

Because artifacts are plain validated JSON, they move through CI, dashboards, and review tools without lock-in.

taskscore.schema.json (excerpt)
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "TaskScore",
  "type": "object",
  "required": ["case", "claim", "verdict", "evidence"],
  "properties": {
    "case":     { "type": "string" },
    "claim":    { "type": "string" },
    "verdict":  { "enum": ["merge", "warn", "block"] },
    "confidence": { "type": "number", "minimum": 0, "maximum": 1 },
    "acceptance": {
      "type": "object",
      "properties": {
        "passed": { "type": "integer" },
        "failed": { "type": "integer" }
      }
    },
    "evidence": { "type": "array", "items": { "type": "string" } }
  }
}
Interoperability

Designed to fit existing pipelines

VLS is meant to interoperate with the tools teams already run, not replace them.

GitHub / CI checksSARIFOpenTelemetryMCP
Neutral by design

An open standard, owned by no single tool

VLS is built to stay vendor-neutral: published schemas, a conformance corpus, and room for independent implementations, so the artifact format is never locked to a single tool.

Private beta repository. Public VLS/Timaeus release in progress.