diff --git a/docs/superpowers/plans/2026-07-11-adapter-foundations.md b/docs/superpowers/plans/2026-07-11-adapter-foundations.md
index a32f475e..b11fc8ea 100644
--- a/docs/superpowers/plans/2026-07-11-adapter-foundations.md
+++ b/docs/superpowers/plans/2026-07-11-adapter-foundations.md
@@ -289,6 +289,11 @@ git commit -m "feat(config): add typed resource schema"
 - Produces: `build_dwh(cfg: Config) -> DwhAdapter` and `build_vector_store(cfg: Config, *, require_write: bool = False) -> VectorStore`.
 - Consumes: resource configs from Task 4 and wrappers from Tasks 2-3.
 
+Correction: `DwhAdapter.distinct_values(table, column, *, limit)` requires an explicit
+positive limit, and direct DWH construction injects `cfg.execution.statement_timeout_ms`.
+Targeted vector writes consume the factory-returned `VectorStore` and pass
+`VectorWriteRecord` objects to `upsert`.
+
 - [ ] **Step 1: Write exact factory selection and missing-writer tests**
 
 ```python
diff --git a/harness/tests/l2/test_memory_save_one_real.py b/harness/tests/l2/test_memory_save_one_real.py
index bc98c283..c7e2aa74 100644
--- a/harness/tests/l2/test_memory_save_one_real.py
+++ b/harness/tests/l2/test_memory_save_one_real.py
@@ -39,7 +39,10 @@ def test_save_one_upserts_to_real_pgvector(l2_env):
         detail="ablazione", rationale="L2 self-test (idempotent)",
         question_context="ablazione 2025", tables=["fct_ricoveri"], concepts=[],
     )
-    upserted = save_one_memory([record], decision_seq=999, writer=writer, embedder=embedder)
+    from tht.adapters.vector import ThothHttpVectorStore
+
+    store = ThothHttpVectorStore(reader=writer, writer=writer)
+    upserted = save_one_memory([record], decision_seq=999, store=store, embedder=embedder)
     assert upserted >= 0  # idempotent: 0 on unchanged, >=1 on new/updated
 
     # read it back via the READER key (vector_rest, path /vector/v1/)
diff --git a/harness/tests/test_adapter_factory.py b/harness/tests/test_adapter_factory.py
index cf0f2f4b..52cf75ed 100644
--- a/harness/tests/test_adapter_factory.py
+++ b/harness/tests/test_adapter_factory.py
@@ -84,3 +84,9 @@ def test_factory_selects_direct_vector_reader():
     assert isinstance(build_vector_store(config), LegacyDirectVectorStore)
     with pytest.raises(ConfigError, match="writer"):
         build_vector_store(config, require_write=True)
+
+
+def test_factory_propagates_non_default_statement_timeout():
+    config = _config(dwh_type="postgres_direct")
+    config.execution.statement_timeout_ms = 12_345
+    assert build_dwh(config)._statement_timeout_ms == 12_345
diff --git a/harness/tests/test_dwh_adapters.py b/harness/tests/test_dwh_adapters.py
index fdb88b62..985b9d4b 100644
--- a/harness/tests/test_dwh_adapters.py
+++ b/harness/tests/test_dwh_adapters.py
@@ -85,14 +85,17 @@ def test_postgres_sampling_delegates_to_paired_sampling_functions(monkeypatch):
         )
         or ["A", "B"],
     )
+    distinct_calls = []
     monkeypatch.setattr(
         "tht.adapters.dwh.postgres.sampling.distinct_values",
-        lambda engine, schema, table, column: expected,
+        lambda engine, schema, table, column, *, max_values: distinct_calls.append(max_values)
+        or expected,
     )
 
     assert adapter.sample_column("sales", "region", limit=2) == ["A", "B"]
     assert calls == [(adapter._engine, "dw", "sales", "region", 2)]
-    assert adapter.distinct_values("sales", "region") is expected
+    assert adapter.distinct_values("sales", "region", limit=17) is expected
+    assert distinct_calls == [17]
 
 
 def test_rest_sampling_delegates_and_translates_transport_errors(monkeypatch):
@@ -104,10 +107,10 @@ def test_rest_sampling_delegates_and_translates_transport_errors(monkeypatch):
     )
     monkeypatch.setattr(
         "tht.adapters.dwh.thoth_rest.sampling.distinct_values_rest",
-        lambda client, schema, table, column: expected,
+        lambda client, schema, table, column, *, max_values: expected,
     )
     assert adapter.sample_column("sales", "region", limit=2) == ["A", "B"]
-    assert adapter.distinct_values("sales", "region") is expected
+    assert adapter.distinct_values("sales", "region", limit=17) is expected
 
     def fail(*args, **kwargs):
         raise RestError("transport failed")
@@ -117,7 +120,7 @@ def test_rest_sampling_delegates_and_translates_transport_errors(monkeypatch):
     with pytest.raises(ExecutionError, match="transport failed"):
         adapter.sample_column("sales", "region", limit=2)
     with pytest.raises(ExecutionError, match="transport failed"):
-        adapter.distinct_values("sales", "region")
+        adapter.distinct_values("sales", "region", limit=17)
 
 
 def test_rest_distinct_values_reports_transport_truncation():
diff --git a/harness/tests/test_dwh_port_contract.py b/harness/tests/test_dwh_port_contract.py
index 8899d608..55e7bac9 100644
--- a/harness/tests/test_dwh_port_contract.py
+++ b/harness/tests/test_dwh_port_contract.py
@@ -31,7 +31,7 @@ class FakeDwhAdapter:
     def sample_column(self, table: str, column: str, *, limit: int) -> list[object]:
         raise NotImplementedError
 
-    def distinct_values(self, table: str, column: str) -> DistinctValues:
+    def distinct_values(self, table: str, column: str, *, limit: int) -> DistinctValues:
         raise NotImplementedError
 
 
diff --git a/harness/tests/test_memory_metadata.py b/harness/tests/test_memory_metadata.py
index 673bb488..4e5ed79d 100644
--- a/harness/tests/test_memory_metadata.py
+++ b/harness/tests/test_memory_metadata.py
@@ -56,12 +56,12 @@ def test_save_one_memory_preserves_subject_through_upsert_row():
     from tht.memory import save_one_memory
 
     writer = MagicMock()
-    writer.upsert_records.return_value = 1
+    writer.upsert.return_value = 1
     embedder = MagicMock()
     embedder.embed_documents.return_value = [[0.0] * 8]
-    save_one_memory([_record(decision_seq=1)], decision_seq=1, writer=writer, embedder=embedder)
-    row = writer.upsert_records.call_args[0][1][0]
-    md = row["metadata"]
+    save_one_memory([_record(decision_seq=1)], decision_seq=1, store=writer, embedder=embedder)
+    row = writer.upsert.call_args[0][1][0]
+    md = row.record.metadata
     assert md["subject"] == "dim_pazienti"
     assert md["detail"] == "promossa"
     assert md["rationale"] == "perche' serve"
diff --git a/harness/tests/test_memory_save_one.py b/harness/tests/test_memory_save_one.py
index e686cc6a..7a679668 100644
--- a/harness/tests/test_memory_save_one.py
+++ b/harness/tests/test_memory_save_one.py
@@ -8,11 +8,8 @@ pgvector as a one-row upsert. This test pins the pure core of that behavior:
 - writer.sync is NEVER called (that is the full-resync path)
 """
 from datetime import datetime
-from pathlib import Path
 from unittest.mock import MagicMock
 
-import pytest
-
 from tht.memory import MemoryRecord, memory_vector_record_for_decision, save_one_memory
 
 
@@ -47,31 +44,31 @@ def test_returns_none_for_unknown_decision_seq():
 def test_save_one_calls_upsert_with_single_row_never_sync():
     records = [_record(seq=7)]
     writer = MagicMock()
-    writer.upsert_records.return_value = 1
+    writer.upsert.return_value = 1
     embedder = MagicMock()
     embedder.embed_documents.return_value = [[0.1] * 8]
 
-    upserted = save_one_memory(records, decision_seq=7, writer=writer, embedder=embedder)
+    upserted = save_one_memory(records, decision_seq=7, store=writer, embedder=embedder)
 
     assert upserted == 1
     writer.sync.assert_not_called()  # the whole point of D11: no full resync
-    writer.upsert_records.assert_called_once()
-    args = writer.upsert_records.call_args
+    writer.upsert.assert_called_once()
+    args = writer.upsert.call_args
     # table is memory, exactly one row
     assert args[0][0] == "memory"
     rows = args[0][1]
     assert len(rows) == 1
-    assert rows[0]["record_key"] == "memory:mem-0007"
-    assert "embedding" in rows[0]
+    assert rows[0].record.id == "memory:mem-0007"
+    assert rows[0].embedding
 
 
 def test_save_one_no_record_for_seq_is_noop():
     records = [_record(seq=7)]
     writer = MagicMock()
     embedder = MagicMock()
-    upserted = save_one_memory(records, decision_seq=42, writer=writer, embedder=embedder)
+    upserted = save_one_memory(records, decision_seq=42, store=writer, embedder=embedder)
     assert upserted == 0
-    writer.upsert_records.assert_not_called()
+    writer.upsert.assert_not_called()
     writer.sync.assert_not_called()
     embedder.embed_documents.assert_not_called()
 
@@ -81,9 +78,9 @@ def test_save_one_uses_writer_key_for_upsert():
     Verified indirectly: save_one_memory takes the writer as its client argument."""
     records = [_record(seq=7)]
     writer = MagicMock()
-    writer.upsert_records.return_value = 1
+    writer.upsert.return_value = 1
     embedder = MagicMock()
     embedder.embed_documents.return_value = [[0.0] * 4]
-    save_one_memory(records, decision_seq=7, writer=writer, embedder=embedder)
+    save_one_memory(records, decision_seq=7, store=writer, embedder=embedder)
     # one upsert call, single row, table=memory
-    assert writer.upsert_records.call_count == 1
+    assert writer.upsert.call_count == 1
diff --git a/harness/tests/test_schema_introspect_guard.py b/harness/tests/test_schema_introspect_guard.py
index 056e361f..80fe6f2a 100644
--- a/harness/tests/test_schema_introspect_guard.py
+++ b/harness/tests/test_schema_introspect_guard.py
@@ -4,6 +4,8 @@ from typer.testing import CliRunner
 
 from tht.cli import app
 from tht.mschema.models import ColumnPhysical, PhysicalSchema, TablePhysical
+from tht.config import ExamplesConfig
+from tht.cli.schema_cmd import _add_examples
 
 
 def _write_catalog(tmp_path):
@@ -68,3 +70,23 @@ def test_render_without_catalog_guides_fallback(tmp_path):
     res = CliRunner().invoke(app, ["schema", "render", "-c", str(cfg)])
     assert res.exit_code == 1
     assert "Esegui prima" in res.output
+
+
+def test_examples_skip_one_unreadable_column_and_continue(caplog):
+    physical = PhysicalSchema(
+        database="d", schema="s", introspected_at=datetime(2026, 1, 1),
+        tables={"t": TablePhysical(columns={
+            "bad": ColumnPhysical(type="text"), "good": ColumnPhysical(type="text")
+        })},
+    )
+
+    class Dwh:
+        def sample_column(self, table, column, *, limit):
+            if column == "bad":
+                raise RuntimeError("denied")
+            return ["kept"]
+
+    _add_examples(Dwh(), physical, ExamplesConfig(max_per_column=3))
+    assert physical.tables["t"].columns["bad"].examples == []
+    assert physical.tables["t"].columns["good"].examples == ["kept"]
+    assert "Campionamento saltato" in caplog.text
diff --git a/harness/tests/test_solved_question.py b/harness/tests/test_solved_question.py
index 54c4fb62..91c9e5d0 100644
--- a/harness/tests/test_solved_question.py
+++ b/harness/tests/test_solved_question.py
@@ -43,18 +43,18 @@ def test_solved_kind_maps_to_memory_table():
 def test_save_upserts_single_row_into_memory_table():
     writer = MagicMock()
     writer.existing_hashes.return_value = {}
-    writer.upsert_records.return_value = 1
+    writer.upsert.return_value = 1
     embedder = MagicMock()
     embedder.embed_documents.return_value = [[0.1] * 8]
 
-    assert save_solved_question(_rec(), writer=writer, embedder=embedder) == 1
+    assert save_solved_question(_rec(), store=writer, embedder=embedder) == 1
     writer.sync.assert_not_called()
-    table, rows = writer.upsert_records.call_args[0]
+    table, rows = writer.upsert.call_args[0]
     assert table == "memory"
     assert len(rows) == 1
-    assert rows[0]["record_key"] == "solved:s1"
-    assert rows[0]["metadata"]["kind"] == SOLVED_KIND
-    assert rows[0]["metadata"]["sql"].startswith("SELECT")
+    assert rows[0].record.id == "solved:s1"
+    assert rows[0].record.kind == SOLVED_KIND
+    assert rows[0].record.metadata["sql"].startswith("SELECT")
 
 
 def test_save_skips_when_question_and_sql_unchanged():
@@ -62,9 +62,9 @@ def test_save_skips_when_question_and_sql_unchanged():
     writer = MagicMock()
     writer.existing_hashes.return_value = {r.id: _solved_hash(r)}
     embedder = MagicMock()
-    assert save_solved_question(r, writer=writer, embedder=embedder) == 0
+    assert save_solved_question(r, store=writer, embedder=embedder) == 0
     embedder.embed_documents.assert_not_called()
-    writer.upsert_records.assert_not_called()
+    writer.upsert.assert_not_called()
 
 
 def test_sql_change_alone_triggers_reupsert():
@@ -72,7 +72,7 @@ def test_sql_change_alone_triggers_reupsert():
     new = _rec(sql="SELECT 1")  # stessa domanda, SQL diverso
     writer = MagicMock()
     writer.existing_hashes.return_value = {old.id: _solved_hash(old)}
-    writer.upsert_records.return_value = 1
+    writer.upsert.return_value = 1
     embedder = MagicMock()
     embedder.embed_documents.return_value = [[0.0] * 4]
-    assert save_solved_question(new, writer=writer, embedder=embedder) == 1
+    assert save_solved_question(new, store=writer, embedder=embedder) == 1
diff --git a/harness/tht/adapters/dwh/postgres.py b/harness/tht/adapters/dwh/postgres.py
index 2041ba82..58356b6b 100644
--- a/harness/tht/adapters/dwh/postgres.py
+++ b/harness/tht/adapters/dwh/postgres.py
@@ -4,7 +4,7 @@ from tht.config import DatabaseConfig
 from sqlalchemy.exc import SQLAlchemyError
 
 from tht.db import execute, sampling
-from tht.db.connection import make_engine, ping
+from tht.db.connection import can_create_in_schema, make_engine, ping, writable_tables
 from tht.db.introspect import introspect
 from tht.execute import ExecResult, PlanSummary
 from tht.mschema.models import PhysicalSchema
@@ -14,32 +14,39 @@ from tht.ports.dwh import DistinctValues, DwhCapabilities, DwhHealth
 class PostgresDwhAdapter:
     capabilities = DwhCapabilities()
 
-    def __init__(self, config: DatabaseConfig):
+    def __init__(self, config: DatabaseConfig, *, statement_timeout_ms: int = 30_000):
         self._config = config
         self._engine = make_engine(config)
+        self._statement_timeout_ms = statement_timeout_ms
 
     def health(self) -> DwhHealth:
         try:
             ping(self._engine)
         except SQLAlchemyError as exc:
             return DwhHealth(ok=False, detail=str(exc))
-        return DwhHealth(ok=True)
+        writable = tuple(writable_tables(self._engine, self._config.db_schema))
+        can_create = can_create_in_schema(self._engine, self._config.db_schema)
+        return DwhHealth(ok=True, database=self._config.database, schema=self._config.db_schema,
+                         read_only=not writable and not can_create,
+                         writable_tables=writable, can_create=can_create)
 
     def introspect(self) -> PhysicalSchema:
         return introspect(self._engine, self._config.database, self._config.db_schema)
 
     def run_query(self, sql: str, *, limit: int) -> ExecResult:
-        return execute.run_query(self._engine, sql, limit=limit)
+        return execute.run_query(
+            self._engine, sql, limit=limit, timeout_ms=self._statement_timeout_ms
+        )
 
     def explain(self, sql: str) -> PlanSummary:
-        return execute.explain(self._engine, sql)
+        return execute.explain(self._engine, sql, timeout_ms=self._statement_timeout_ms)
 
     def sample_column(self, table: str, column: str, *, limit: int) -> list[object]:
         return sampling.sample_column(
             self._engine, self._config.db_schema, table, column, limit=limit
         )
 
-    def distinct_values(self, table: str, column: str) -> DistinctValues:
+    def distinct_values(self, table: str, column: str, *, limit: int) -> DistinctValues:
         return sampling.distinct_values(
-            self._engine, self._config.db_schema, table, column
+            self._engine, self._config.db_schema, table, column, max_values=limit
         )
diff --git a/harness/tht/adapters/dwh/thoth_rest.py b/harness/tht/adapters/dwh/thoth_rest.py
index beac1781..e1f1c321 100644
--- a/harness/tht/adapters/dwh/thoth_rest.py
+++ b/harness/tht/adapters/dwh/thoth_rest.py
@@ -22,8 +22,10 @@ class ThothRestDwhAdapter:
             result = self._client.ping()
         except RestError as exc:
             return DwhHealth(ok=False, detail=str(exc))
-        ok = bool(result.get("db_connected", True))
-        return DwhHealth(ok=ok, detail=None if ok else str(result))
+        ok = bool(result.get("db_connected") and result.get("schema_accessible"))
+        return DwhHealth(ok=ok, detail=None if ok else str(result),
+                         database=self._database.database, schema=self._database.db_schema,
+                         endpoint=self._client.cfg.base_url, read_only=True)
 
     def introspect(self) -> PhysicalSchema:
         return introspect_rest(
@@ -44,10 +46,10 @@ class ThothRestDwhAdapter:
         except RestError as exc:
             raise ExecutionError(str(exc)) from exc
 
-    def distinct_values(self, table: str, column: str) -> DistinctValues:
+    def distinct_values(self, table: str, column: str, *, limit: int) -> DistinctValues:
         try:
             return sampling.distinct_values_rest(
-                self._client, self._database.db_schema, table, column
+                self._client, self._database.db_schema, table, column, max_values=limit
             )
         except RestError as exc:
             raise ExecutionError(str(exc)) from exc
diff --git a/harness/tht/adapters/factory.py b/harness/tht/adapters/factory.py
index 61fffa60..a30fdc17 100644
--- a/harness/tht/adapters/factory.py
+++ b/harness/tht/adapters/factory.py
@@ -14,7 +14,10 @@ def build_dwh(cfg: Config) -> DwhAdapter:
     resource = cfg.dwh
     match resource.type:
         case "postgres_direct":
-            return PostgresDwhAdapter(resource.connection)
+            return PostgresDwhAdapter(
+                resource.connection,
+                statement_timeout_ms=cfg.execution.statement_timeout_ms,
+            )
         case "thoth_rest":
             return ThothRestDwhAdapter(resource.database, resource.endpoint)
         case other:  # pragma: no cover - Pydantic's discriminator rejects this first.
diff --git a/harness/tht/cli/db_cmd.py b/harness/tht/cli/db_cmd.py
index 28ed309a..a1d06b65 100644
--- a/harness/tht/cli/db_cmd.py
+++ b/harness/tht/cli/db_cmd.py
@@ -1,43 +1,14 @@
 from pathlib import Path
 
 import typer
-from sqlalchemy.exc import OperationalError
-
-from tht.adapters.dwh import ThothRestDwhAdapter
 from tht.adapters.factory import build_dwh
 from tht.cli.config_cmd import CONFIG_OPT
 from tht.config import ConfigError, load_config
-from tht.db.connection import can_create_in_schema, make_engine, ping, writable_tables
 from tht.db.fetch_ca import CaFetchError, describe_pem, fetch_chain_pem, parse_host_port
 
 db_app = typer.Typer(help="Operazioni sul database target")
 
 
-def _ping_rest(adapter: ThothRestDwhAdapter, cfg, schema: str) -> None:
-    """Health check via REST. Il read-only è garantito strutturalmente dall'API
-    (ammette solo SELECT/WITH): non serve il controllo dei privilegi di scrittura."""
-    from tht.rest.client import RestError
-
-    try:
-        info = adapter._client.ping()
-    except RestError as e:
-        typer.secho(f"ERRORE di connessione: {e}", fg=typer.colors.RED, err=True)
-        raise typer.Exit(code=1)
-    if not info.get("db_connected") or not info.get("schema_accessible"):
-        typer.secho(
-            f"ERRORE: DWH non accessibile via REST (risposta: {info}).",
-            fg=typer.colors.RED,
-            err=True,
-        )
-        raise typer.Exit(code=1)
-    typer.secho(
-        f"OK: connesso via REST a {cfg.rest.base_url} (schema {schema})", fg=typer.colors.GREEN
-    )
-    typer.secho(
-        "OK: accesso read-only garantito dall'API (solo SELECT/WITH).", fg=typer.colors.GREEN
-    )
-
-
 @db_app.command("ping")
 def ping_cmd(config: Path = CONFIG_OPT) -> None:
     """Testa la connessione e verifica che l'utente sia effettivamente read-only."""
@@ -46,29 +17,26 @@ def ping_cmd(config: Path = CONFIG_OPT) -> None:
     except ConfigError as e:
         typer.secho(f"ERRORE: {e}", fg=typer.colors.RED, err=True)
         raise typer.Exit(code=1)
-    schema = cfg.database.db_schema
-    adapter = build_dwh(cfg)
-    if isinstance(adapter, ThothRestDwhAdapter):
-        _ping_rest(adapter, cfg, schema)
-        return
-    engine = make_engine(cfg.database)
-    try:
-        ping(engine)
-    except OperationalError as e:
-        typer.secho(f"ERRORE di connessione: {e.orig}", fg=typer.colors.RED, err=True)
+    health = build_dwh(cfg).health()
+    if not health.ok:
+        typer.secho(f"ERRORE di connessione: {health.detail}", fg=typer.colors.RED, err=True)
         raise typer.Exit(code=1)
-    typer.secho(f"OK: connesso a {cfg.database.database} (schema {schema})", fg=typer.colors.GREEN)
-
-    writable = writable_tables(engine, schema)
-    can_create = can_create_in_schema(engine, schema)
-    if writable or can_create:
+    if health.endpoint:
+        typer.secho(f"OK: connesso via REST a {health.endpoint} (schema {health.schema})",
+                    fg=typer.colors.GREEN)
+        typer.secho("OK: accesso read-only garantito dall'API (solo SELECT/WITH).",
+                    fg=typer.colors.GREEN)
+        return
+    typer.secho(f"OK: connesso a {health.database} (schema {health.schema})",
+                fg=typer.colors.GREEN)
+    if not health.read_only:
         typer.secho(
             f"ERRORE: l'utente '{cfg.database.user}' NON e' read-only.", fg=typer.colors.RED, err=True
         )
-        if writable:
-            typer.echo(f"  Tabelle scrivibili: {', '.join(writable[:10])}", err=True)
-        if can_create:
-            typer.echo(f"  L'utente puo' creare oggetti nello schema {schema}.", err=True)
+        if health.writable_tables:
+            typer.echo(f"  Tabelle scrivibili: {', '.join(health.writable_tables[:10])}", err=True)
+        if health.can_create:
+            typer.echo(f"  L'utente puo' creare oggetti nello schema {health.schema}.", err=True)
         typer.echo("  Crea un ruolo read-only con scripts/create_readonly_role.sql.", err=True)
         raise typer.Exit(code=2)
     typer.secho("OK: l'utente e' read-only sullo schema target.", fg=typer.colors.GREEN)
diff --git a/harness/tht/cli/lsh_cmd.py b/harness/tht/cli/lsh_cmd.py
index a275633f..f1916fcc 100644
--- a/harness/tht/cli/lsh_cmd.py
+++ b/harness/tht/cli/lsh_cmd.py
@@ -47,7 +47,9 @@ def build_cmd(config: Path = CONFIG_OPT) -> None:
             if not is_text_type(column.type) or not effective_eligibility(column, ann_col)[0]:
                 continue
             try:
-                distinct = dwh.distinct_values(table_name, column_name)
+                distinct = dwh.distinct_values(
+                    table_name, column_name, limit=cfg.lsh.max_values_per_column
+                )
             except Exception as e:
                 skipped.append(SkippedColumn(table_name, column_name, f"errore: {e}"))
                 continue
diff --git a/harness/tht/cli/memory_cmd.py b/harness/tht/cli/memory_cmd.py
index 9ba16ca6..982f1abb 100644
--- a/harness/tht/cli/memory_cmd.py
+++ b/harness/tht/cli/memory_cmd.py
@@ -156,7 +156,6 @@ def save_one_cmd(
     from tht.adapters.factory import build_vector_store
     from tht.cli.vector_cmd import make_embedder
     from tht.memory import load_registry, promote, save_one_memory
-    from tht.vectorstore.rest_client import VectorRestClient
 
     cfg = _load_config_or_exit(config)
     manifest = load_session_or_exit(cfg, session)
@@ -168,7 +167,7 @@ def save_one_cmd(
             fg=typer.colors.RED, err=True,
         )
         raise typer.Exit(code=4)
-    build_vector_store(cfg, require_write=True)
+    store = build_vector_store(cfg, require_write=True)
 
     sdir = session_dir(cfg, session)
     # Promuove la decisione scelta nel registro locale (idempotente: salta se gia' presente
@@ -176,9 +175,8 @@ def save_one_cmd(
     promote(sdir, manifest, seqs=[decision], registry_path=registry_path(cfg))
     records = [r for r in load_registry(registry_path(cfg)) if r.session_id == manifest.id]
 
-    writer = VectorRestClient(cfg.vector_write_rest)
     embedder = make_embedder(cfg.embeddings)
-    count = save_one_memory(records, decision, writer=writer, embedder=embedder)
+    count = save_one_memory(records, decision, store=store, embedder=embedder)
 
     msg = (
         f"{count} memoria salvata su pgvector (decision_seq {decision})."
@@ -455,21 +453,20 @@ def index_solved_session(cfg, session_id: str) -> int:
     from tht.cli.sql_cmd import promoted_tables_for
     from tht.cli.vector_cmd import make_embedder
     from tht.solved import build_solved_record, save_solved_question
-    from tht.vectorstore.rest_client import VectorRestClient
 
     if not has_vector_write_rest(cfg):
         raise RuntimeError(
             "vector_write_rest assente: la coppia domanda->SQL si indicizza solo con la "
             "writer key configurata nel workspace yaml"
         )
-    build_vector_store(cfg, require_write=True)
+    store = build_vector_store(cfg, require_write=True)
     manifest = load_session_or_exit(cfg, session_id)
     record = build_solved_record(
         session_dir(cfg, session_id), manifest, promoted_tables_for(cfg, session_id)
     )
     return save_solved_question(
         record,
-        writer=VectorRestClient(cfg.vector_write_rest),
+        store=store,
         embedder=make_embedder(cfg.embeddings),
     )
 
diff --git a/harness/tht/cli/schema_cmd.py b/harness/tht/cli/schema_cmd.py
index f8fe23aa..c0cfacd5 100644
--- a/harness/tht/cli/schema_cmd.py
+++ b/harness/tht/cli/schema_cmd.py
@@ -1,4 +1,5 @@
 from pathlib import Path
+import logging
 
 import typer
 from tht.adapters.factory import build_dwh
@@ -8,6 +9,23 @@ from tht.db.sampling import is_text_type
 from tht.mschema.eligibility import classify_all
 
 schema_app = typer.Typer(help="Gestione mschema (rappresentazione canonica dello schema)")
+logger = logging.getLogger(__name__)
+
+
+def _add_examples(dwh, phys, examples) -> None:
+    for table_name, table in phys.tables.items():
+        for column_name, column in table.columns.items():
+            if not is_text_type(column.type):
+                continue
+            try:
+                sampled = dwh.sample_column(
+                    table_name, column_name, limit=examples.max_per_column
+                )
+            except Exception as exc:
+                logger.warning("Campionamento saltato per %s.%s: %s",
+                               table_name, column_name, exc)
+                continue
+            column.examples = [str(value) for value in sampled if value not in (None, "")]
 
 
 def _load_config_or_exit(config: Path):
@@ -64,18 +82,7 @@ def introspect_cmd(
     try:
         dwh = build_dwh(cfg)
         phys = dwh.introspect()
-        for table_name, table in phys.tables.items():
-            for column_name, column in table.columns.items():
-                if is_text_type(column.type):
-                    column.examples = [
-                        str(value)
-                        for value in dwh.sample_column(
-                            table_name,
-                            column_name,
-                            limit=cfg.examples.max_per_column,
-                        )
-                        if value not in (None, "")
-                    ]
+        _add_examples(dwh, phys, cfg.examples)
         classify_all(phys, cfg.eligibility)
     except Exception as e:
         typer.secho(f"ERRORE: {e}", fg=typer.colors.RED, err=True)
diff --git a/harness/tht/db/execute.py b/harness/tht/db/execute.py
index 61e74c8f..75fab3c6 100644
--- a/harness/tht/db/execute.py
+++ b/harness/tht/db/execute.py
@@ -13,15 +13,15 @@ from tht.execute import (
 DEFAULT_TIMEOUT_MS = 30_000
 
 
-def run_query(engine: Engine, sql: str, *, limit: int) -> ExecResult:
+def run_query(engine: Engine, sql: str, *, limit: int, timeout_ms: int = DEFAULT_TIMEOUT_MS) -> ExecResult:
     limit = require_positive_int(limit, name="limit")
     return run_controlled(
         engine,
         sql,
         limit=limit,
-        timeout_ms=DEFAULT_TIMEOUT_MS,
+        timeout_ms=timeout_ms,
     )
 
 
-def explain(engine: Engine, sql: str) -> PlanSummary:
-    return _explain(engine, sql, timeout_ms=DEFAULT_TIMEOUT_MS)
+def explain(engine: Engine, sql: str, *, timeout_ms: int = DEFAULT_TIMEOUT_MS) -> PlanSummary:
+    return _explain(engine, sql, timeout_ms=timeout_ms)
diff --git a/harness/tht/memory.py b/harness/tht/memory.py
index e081b478..8a6acc78 100644
--- a/harness/tht/memory.py
+++ b/harness/tht/memory.py
@@ -255,7 +255,7 @@ def memory_vector_record_for_decision(
 
 
 def save_one_memory(
-    records: list[MemoryRecord], decision_seq: int, *, writer, embedder
+    records: list[MemoryRecord], decision_seq: int, *, store, embedder
 ) -> int:
     """Targeted one-row upsert of a promoted decision to pgvector via the writer key
     (spec D11). This is NOT a full vectorstore resync: it embeds and pushes a single
@@ -267,27 +267,22 @@ def save_one_memory(
     the writer's existing_vector_hashes; the embedding (Ollama round-trip) and the
     upsert are skipped when the content is unchanged. Idempotent by construction.
 
-    `writer` is a VectorRestClient (writer key); `embedder` an embeddings client.
+    `store` is the configured writable VectorStore; `embedder` an embeddings client.
     The destructive cleanup (sync's delete-stale step) is intentionally absent: it
     remains a server-side-only operation via the direct vectordb connection.
     """
-    from tht.vectorstore.rest_writer import pack_metadata
+    from tht.ports.vector import VectorWriteRecord
     from tht.vectorstore.store import content_hash
 
     record = memory_vector_record_for_decision(records, decision_seq)
     if record is None:
         return 0
     new_hash = content_hash(record.content)
-    existing = writer.existing_hashes("memory", ["memory"])
+    existing = store.existing_hashes("memory", ["memory"])
     if existing.get(record.id) == new_hash:
         return 0  # unchanged: skip embedding + upsert
     embedding = embedder.embed_documents([record.content])[0]
-    row = {
-        "record_key": record.id,
-        "kind": record.kind,
-        "content_hash": new_hash,
-        "metadata": pack_metadata(record),
-        "embedding": embedding,
-    }
-    return writer.upsert_records("memory", [row])
-
+    return store.upsert(
+        "memory",
+        [VectorWriteRecord(record=record, embedding=embedding, content_hash=new_hash)],
+    )
diff --git a/harness/tht/ports/dwh.py b/harness/tht/ports/dwh.py
index 0e511008..d30dc71a 100644
--- a/harness/tht/ports/dwh.py
+++ b/harness/tht/ports/dwh.py
@@ -19,6 +19,12 @@ class DwhCapabilities:
 class DwhHealth:
     ok: bool
     detail: str | None = None
+    database: str | None = None
+    schema: str | None = None
+    endpoint: str | None = None
+    read_only: bool | None = None
+    writable_tables: tuple[str, ...] = ()
+    can_create: bool = False
 
 
 @dataclass(frozen=True)
@@ -46,4 +52,4 @@ class DwhAdapter(Protocol):
 
     def sample_column(self, table: str, column: str, *, limit: int) -> list[object]: ...
 
-    def distinct_values(self, table: str, column: str) -> DistinctValues: ...
+    def distinct_values(self, table: str, column: str, *, limit: int) -> DistinctValues: ...
diff --git a/harness/tht/solved.py b/harness/tht/solved.py
index 96de27e5..e62910de 100644
--- a/harness/tht/solved.py
+++ b/harness/tht/solved.py
@@ -43,25 +43,22 @@ def _solved_hash(record: VectorRecord) -> str:
     return content_hash(record.content + "\n" + str(record.metadata.get("sql", "")))
 
 
-def save_solved_question(record: VectorRecord, *, writer, embedder) -> int:
+def save_solved_question(record: VectorRecord, *, store, embedder) -> int:
     """Upsert one-row della coppia domanda->SQL via writer key (stesso pattern di
     save_one_memory, spec D11): hash dedup client-side, embedding solo se domanda
     o SQL sono cambiati. `writer` e' un VectorRestClient (writer key). Ritorna il
     numero di righe upsertate (0 = invariata)."""
-    from tht.vectorstore.rest_writer import pack_metadata
+    from tht.ports.vector import VectorWriteRecord
 
     new_hash = _solved_hash(record)
-    existing = writer.existing_hashes("memory", [SOLVED_KIND])
+    existing = store.existing_hashes("memory", [SOLVED_KIND])
     if existing.get(record.id) == new_hash:
         return 0
     embedding = embedder.embed_documents([record.content])[0]
-    return writer.upsert_records("memory", [{
-        "record_key": record.id,
-        "kind": record.kind,
-        "content_hash": new_hash,
-        "metadata": pack_metadata(record),
-        "embedding": embedding,
-    }])
+    return store.upsert(
+        "memory",
+        [VectorWriteRecord(record=record, embedding=embedding, content_hash=new_hash)],
+    )
 
 
 class SolvedIndexError(Exception):