An early preview of how provenance could work with AI-generated documents. Verifiable links between claims and their sources — with drift detection, background verification of every distilled context, in-app authoring, and an MCP surface your agent can use.
Select a claim in a note or distilled context, navigate to the saved article that backs it, and Sombra suggests passages that match. Click one to commit — the citation is anchored verbatim and stays linked over time.
Mainland Europe's westernmost capital city — Lisbon is one of Europe's best food cities at nearly every price point.
▸There's no denying that some of the best restaurants in Lisbon are the most talked-about in Europe right now.
Demo replays automatically. Tap any step to step through manually.
Citations don't break silently. The server resolves each one against current source content at read time — and tells you exactly what shifted when the underlying text changes.
The article confirms that Lisbon's tram 28 climbs the city's seven hills on a route the city has run since 1914.
Coincident — the cited text still appears at the original location.
The article confirms that tram 28 winds across Lisbon's seven hills — running roughly the same route since 1914.
Drifted — the source has been edited; the matcher relocates and surfaces what shifted.
Every citation is bidirectional. From a claim, jump to the cited passage. From a source artifact, see every collection or note that cites it.
Europe's westernmost capital city, built on seven hills.
Some of the best food in Europe, served from family-run tascas.
The iconic tram 28 climbs the historic centre.
Wikivoyage — Lisbon
Mainland Europe's westernmost capital city, with…
CN Traveler — Best of Lisbon
Some of the best restaurants in Europe right now.
Lisbon transit guide
The tram 28 line climbs through the oldest districts.
Click any highlight to see its counterpart.
AI-generated text needs provenance
When an agent writes a distilled context for a collection, every claim should be traceable to the underlying material. Citations make that audit cheap.
Verifiable by default
Citations only commit when the claim text anchors verbatim. No silent fuzzy matches on the human-authored path; the agent path uses the same matcher but with a configurable confidence threshold and explicit candidates.
Drift over time, not just snapshots
Documents change. Each citation tracks whether its source still says what it said when the citation was made — so you know when context has shifted.
Same substrate, three surfaces
The in-app authoring flow, the background verifier, and the MCP tools all share one data model. Citations authored by an agent, proposed by the scanner, or made by hand show up identically — same chrome, same drift detection, same lifecycle.
Verification, not just authorship
Every time you write a distilled context, Sombra scans it for substantive claims and surfaces what's anchored, partially matched, or unsourced — inline, above the distill. Accept anchored claims in bulk, review borderline matches one-by-one, fix the unsourced. No LLM in the loop: deterministic sentence segmentation plus the same matcher that drives the MCP commit path.
Eight citation tools, available to any MCP client connected to Sombra:
cite_textPropose citations with range + confidence; inspect before commit.
commit_citationsPersist a batch of proposals in one transaction.
find_citationsReverse lookup — what cites a given source artifact or URL?
check_citationsDrift report for active citations on a parent.
supersede_citationReplace a citation; the old version stays in history.
set_citation_stateActive / invalidated / deferred lifecycle transitions.
repair_citationsRe-anchor drifted citations to their current location in the parent.
verify_collection_contextMechanical claim scan on a distilled context — returns per-sentence verdicts (anchored / loose / uncited) and the matcher's confidence. Read-only; for an agent driving a verification workflow.
Full tool descriptions are on the MCP page; the user-facing flow is documented in Docs · Citations.
Citations are live in Sombra today, and they're early preview.
We're using them in our own work and sharing them publicly so we can learn how provenance should feel. If something breaks or the chrome gets in your way, please tell us.