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Schema explorer

Schema is the human view of what the agent sees: every table in a connection, its columns, types, nullability, keys, and comments — plus the governance annotations layered on top.

Pick a connection, then search across tables and column names to find the one you mean. Selecting a table shows:

  • Columns — name, type, nullability, primary and foreign keys, and any comment carried from the warehouse.
  • Cardinality — distinct-value counts where the connector supports them.
  • References — outgoing foreign keys, so you can walk a join path by hand.
  • CREATE TABLE DDL — the reconstructed DDL, copyable.

The schema is cached; re-scanning refreshes it. The same cache backs the agent's list_tables, describe_table, and schema_overview tools, so what you see here is what it sees.

The schema explorer

PII scan​

Scan PII runs a name-based detector across every cached column and reports what it thinks is sensitive, per table, with a suggested rule:

RuleEffect when applied
hashValues are replaced with a stable hash in query results
hideValues are replaced with a redaction marker

The scan is a proposal, not an enforcement — it detects, it does not change behaviour on its own. Detection is available on every plan; enforced redaction on query results is a paid feature (see plan limits).

The scan matches on column names, so it finds email, ssn, phone_number, and misses a sensitive column called field_7. Treat it as a first pass over a schema you do not know, then encode the real answer in annotations.

Annotations: blocking tables and marking columns​

Per-connection annotations are the governance layer under the explorer. Two things they control:

  • Blocked tables. A blocked table is refused at query time — for you, for the agent, for everything going through the gateway. This is how you keep a payroll table out of reach without changing warehouse grants.
  • PII columns. A column marked hash or hide is transformed in results, again for every caller.

Annotations live per connection and are cached with a TTL of SP_ANNOTATIONS_TTL (60 seconds by default), so a change takes effect within a minute without a restart.

  • Governance — the full rule set applied to every query.
  • Schema tools — the MCP equivalents of this page, including schema_diff for detecting drift between scans.
  • Connection health — latency and error rates per connection.