Product Decision: pg_policy

Date: 2026-08-10
Status: Accepted

Decision

Build pg_policy, a PostgreSQL extension that provides an Agent Policy Language (APL) for:

  1. Guardrails — hard allow/deny for agent/tool/data actions
  2. Guidance — soft obligations and advice
  3. Session governance — temporal quotas, prerequisites, ordering
  4. RLS complementarity — helpers and recipes, not a replacement

Language shape

Cedar/Dogwood-inspired vocabulary (permit, forbid, guide, when, temporal windows) authored inside dollar-quoted documents and managed via SQL functions:

SELECT pg_policy.upsert_policy('research_guard', $apl$
forbid
  principal agent "research_bot"
  action tool "execute_sql"
  when { context.statement_type in ["DROP", "TRUNCATE", "ALTER", "CREATE"] }
  reason "Research agents may not run DDL"
$apl$);

Enforcement modes

Mode Behavior
enforce Denies raise an error (or return denied for non-throwing API)
log_only Always allow side; log would-deny
guide Never hard-deny; return obligations/advice

GUC: pg_policy.enforcement_mode

Syntax strategy

Because Postgres extensions cannot extend gram.y, “additional syntax” means:

  • APL documents (primary language)
  • SQL function / procedure API
  • Future: optional ProcessUtility_hook statement firewall

Delivery plan

Version Deliverable
0.1.0 SQL/PL/pgSQL catalog, evaluate, events, examples, docs
0.2.0 pgrx acceleration; CEL or Cedar-backed conditions
0.3.0 RLS compile helpers; AuthZEN mapping
1.0.0 Stable APL; PGXN primary release; multi-version CI

License

PostgreSQL License — community-aligned for extensions.