Metadata source contract

Vaultwarden is a read-only structural source for the knowledge graph. Scion SDK calls the certified vaultwarden-metadata preset, which invokes vaultwarden_metadata_snapshot and receives a vaultwarden.metadata-entities/v1 envelope.

sequenceDiagram
    participant AU as Scion SDK source_sync
    participant MCP as vaultwarden_metadata_snapshot
    participant VW as Vaultwarden API
    participant EG as Epistemic Graph

    AU->>MCP: metadata_snapshot(mode, checkpoint)
    MCP->>VW: sync_vault + server metadata
    VW-->>MCP: provider response
    MCP-->>AU: typed entities, relationships, checkpoint, digest
    AU->>AU: validate manifest allowlists and reconcile semantics
    AU->>EG: one native graph-slice commit

The projection contains only opaque identifiers, type codes, lifecycle timestamps, counts, version strings, and declared relationships. It never contains document text, item or folder names, usernames, passwords, notes, URIs, TOTP values, custom fields, attachment contents, encrypted payloads, or key material.

The preset declares record_mode: typed_entities, an empty content_fields list, and an explicit metadata_fields allowlist. Its deliberately nonexistent text_field makes a generic document adapter fail closed. The old vaultwarden-ciphers document preset and the connector-local graph-write functions no longer exist, so there is one source and one commit authority.

Delta calls accept the last committed ISO-8601 checkpoint. Changed item nodes retain the locally resolved folder, organization, and collection closure required by their edges; an unchanged delta returns an empty, digest-bound structural no-op. Full calls return the complete projection. Reconcile calls also mark the sorted live_ids set as authoritative. Scion SDK alone applies tombstones and advances the checkpoint.

Backfeed is unsupported. The preset and response both declare read-only operation, and backfeed_metadata refuses before making any provider call. A future write-back contract will require a separately reviewed field allowlist and approval boundary.