Trace the sources behind a table

Question: Which recorded sources and transformations feed the loan-period table used for a balance query?

Evidence MCP is a keyed service. Request access and confirm the source systems, read permissions, and receipt-storage policy for your account. This walkthrough uses only a read-only trace. record_evidence and explain_provenance can write retained receipts; do not call them as part of this example.

1. Trace upstream dependencies

In your provisioned MCP client, call evidence.trace_lineage with the catalog key from the table lookup:

{
  "entity_key": "snowflake://edgar_db.property_mart/loan_period_fact",
  "direction": "upstream",
  "depth": 3
}

upstream asks what feeds the table. depth: 3 bounds the traversal; it is not a claim that every source lies within three hops.

2. Interpret the returned chain

An authenticated read-only check on November 3, 2026 returned 26 chain nodes. The trace included recorded CMBS loan-processing and interest-rate-curve dependencies and producing-code pointers. It reported column_lineage_available: false. No source file was opened, no ingestion receipt was verified and no new evidence receipt was stored in this check.

The chain helps locate source and citation pointers for further inspection. It also exposes missingness: this response did not show how the particular scheduled or actual balance column was calculated. A pointer to code or a source table does not by itself prove the balance reported by Data MCP.

If the trail stops

• Treat a missing source or code pointer as a gap in the available lineage. Do not fill the gap with a plausible but unobserved transformation.
• Check whether the requested depth and your account's source scope bounded the trace. A larger traversal may require different access and a separate review.
• Before opening source code or creating a retained receipt, confirm the file authorization, storage location and retention terms with the operator.

For a supported claim check, use Receipts MCP. For the trace tools and coverage limits, see Evidence MCP.