diff --git a/db/002_fixtures.sql b/db/002_fixtures.sql
index d070d53..947b9e4 100644
--- a/db/002_fixtures.sql
+++ b/db/002_fixtures.sql
@@ -285,6 +285,17 @@ VALUES
     (now() - interval '6 days 10 hours',  'PS_STN_ALARM_BITMASK', 'WW-101', 'LEVEL_SIGNAL_FAULT', 1, 'RTN',    NULL, NULL, 'LIT-101 signal restored'),
     (now() - interval '3 days 5 hours',   'PS_STN_ALARM_BITMASK', 'STN-001', 'SETPOINT_REJECTED', 3, 'ACTIVE', 6500, 'mm', 'Setpoint write rejected - start duty level above the spill weir; previous value retained');
 
+-- =============================================================================
+-- Grants. These live HERE and not in 003_roles.sql on purpose: this file starts
+-- with DROP SCHEMA fixture CASCADE, which destroys every grant on it. Grants
+-- belong with the object they are granted on, so a fixture reload keeps them.
+-- Read-only for both roles - nothing writes fixtures except this file.
+-- =============================================================================
+
+GRANT USAGE ON SCHEMA fixture TO agent_ro, cube_rw;
+GRANT SELECT ON ALL TABLES IN SCHEMA fixture TO agent_ro, cube_rw;
+ALTER DEFAULT PRIVILEGES IN SCHEMA fixture GRANT SELECT ON TABLES TO agent_ro, cube_rw;
+
 -- =============================================================================
 -- Sanity check after loading. Expect roughly: 30 days of 1-minute samples on
 -- three tags, ~300 pump-downs, and alarms concentrated in the wet week.
diff --git a/db/003_roles.sql b/db/003_roles.sql
index 42e5ae2..2e59ef1 100644
--- a/db/003_roles.sql
+++ b/db/003_roles.sql
@@ -36,6 +36,13 @@ ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO agent_ro;
 
 -- No sequences, no functions, no temp tables, no schema creation.
 REVOKE ALL ON ALL SEQUENCES IN SCHEMA public FROM agent_ro;
+-- Revoking TEMPORARY from the role alone is not enough: Postgres grants TEMP on
+-- every database to PUBLIC by default, and agent_ro inherits it. Phase 1 gate
+-- caught agent_ro creating a temp table. Revoke it from PUBLIC as well.
+-- Affects every non-superuser on plant (agent_ro, cube_rw). postgres is a
+-- superuser and is unaffected, so the seed load still works. If Cube ever needs
+-- temp tables, grant TEMPORARY back to cube_rw explicitly - never to PUBLIC.
+REVOKE TEMPORARY ON DATABASE plant FROM PUBLIC;
 REVOKE TEMPORARY ON DATABASE plant FROM agent_ro;
 REVOKE CREATE ON SCHEMA public FROM agent_ro;