Artifacts

Agent outputs — reports, patches, diffs, data, screenshots, logs, benchmark results — become first-class artifacts with identity, versioning, and provenance, instead of giant strings passed through messages.

ResearchAgent → "findings" (research, v1)
                    ↓ deriveArtifact()
AnalysisAgent → "findings" (analysis, v1)   provenance.sources → [research v1]
                    ↓ deriveArtifact()
WriterAgent   → "findings" (report,  v1)    provenance.sources → [analysis v1]

Stores

Store	Use
InMemoryArtifactStore	tests, ephemeral sessions
SqliteArtifactStore	durable (WAL, artifacts table, json_extract filters)

API

import { InMemoryArtifactStore, deriveArtifact } from "@nemesis-oss/nexum";

const store = new InMemoryArtifactStore();

const research = store.save({
  name: "findings",
  kind: "research", // report | patch | diff | code | data | screenshot | log | benchmark | research | analysis | custom
  content: "The tool gateway validates every call...",
  tags: ["phase-1"],
  provenance: { agentId: "researcher", runId, traceId },
});

store.latest("findings", "research"); // newest version
store.versions("findings", "research"); // full history, oldest first
store.query({ agentId: "researcher", tags: ["phase-1"], since: Date.now() - 86_400_000 });

const analysis = deriveArtifact(
  store,
  { artifactId: research.id },
  {
    kind: "analysis",
    content: "…",
    provenance: { agentId: "analyst" },
  },
);
// analysis.provenance.sources → [{ artifactId, name }] — the derivation graph is walkable

• Every artifact's contentHash is a sha256 of its content (content-addressed identity).
• Versions are monotonic per (name, kind) — deriving with a new kind starts a new chain while inheriting the chain's name.
• Provenance carries runId/agentId/sessionId/traceId, sources (parent artifacts), and contributing toolCalls — "where did this number come from" is answerable without re-running anything.

Multi-agent handoff

Agents exchange ArtifactReferences (id + version), not payloads — the supervisor pattern uses the store as its shared workspace, and consumers resolve references lazily through whatever store backs the session.