Show the effective access policy: which tables and columns are visible, the row cap, the statement timeout, and whether a database role or RLS claims are active. Call this before querying so you only ask for data that exists in the policy.

List the tables visible under the access policy, with estimated row counts and table comments. Tables outside the policy are not listed and cannot be queried.

Describe one allowlisted table: columns (only those the policy exposes), types, nullability, primary key, foreign key targets, and indexes.

Read rows from one allowlisted table with simple filters (eq/lt/lte/gt/gte/contains) and a limit. Prefer this over run_query for straightforward lookups; use run_query for joins and aggregations.

Run one read-only SELECT against the allowlisted tables. The statement is parsed with the real PostgreSQL grammar and checked against the access policy, then executed inside a read-only transaction with a statement timeout and a row cap. Denials name the rule that triggered them.

Show the query plan for a read-only SELECT without executing it (EXPLAIN, never EXPLAIN ANALYZE). Same policy gate as run_query.