perf(f1): cache-guard schema introspect + F1 toolbox in skill (~-5 min per session)

Transcript analysis (session 2026-07-06-175012, GLM 5.2) showed F1 at 567s:
182s wasted on a useless `tht schema introspect` (re-introspecting the remote
DWH although physical.yaml was already materialized) plus ~220s of model
thinking inflated by ~7 exploratory turns (--help/find/cat). The actual
searches cost ~15s; reviewer gates (~145s, untouched) are the quality contract.

- schema_cmd.py: introspect now exits 0 with "OK (cache)" in ~1s when
  physical.yaml exists; --refresh forces the real re-introspection.
  Deterministic cross-model guarantee, verified live on psd (163 tables, 1.2s).
- SKILL.md: F1 toolbox (only `tht search find` + `tht schema render`; no
  introspect/--help/filesystem browsing; batch all searches in one turn);
  F4 step 1 is render-only with a one-shot introspect fallback.
- tht-gate.js: `tht schema introspect ... --refresh` added to FORBIDDEN
  (maintenance stays shell-only, never in-session).
- tests: 4 new pytest cases (cache hit placement proven with fake credentials,
  refresh bypass, corrupt-catalog fall-through, render fallback message) and
  2 gate anti-bypass JS cases.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

harness/.pi/extensions/gate/__tests__/gate_antibypass.test.js

@@ -0,0 +1,27 @@
+const test = require("node:test");
+const assert = require("node:assert");
+const { createFakePi } = require("./fake_pi_runtime.js");
+
+const installGatePromise = import("../../tht-gate.js").then((m) => m.default);
+
+test("tht schema introspect --refresh e' bloccato in sessione (manutenzione)", async () => {
+  const installGate = await installGatePromise;
+  const { pi } = createFakePi();
+  installGate(pi);
+  const res = await pi.emit("tool_call", {
+    toolName: "bash",
+    input: { command: "tht schema introspect -c workspaces/psd.yaml --refresh" },
+  });
+  assert.equal(res?.block, true);
+});
+
+test("tht schema introspect senza --refresh passa (cache hit innocuo)", async () => {
+  const installGate = await installGatePromise;
+  const { pi } = createFakePi();
+  installGate(pi);
+  const res = await pi.emit("tool_call", {
+    toolName: "bash",
+    input: { command: "tht schema introspect -c workspaces/psd.yaml" },
+  });
+  assert.equal(res, undefined);
+});

harness/.pi/extensions/tht-gate.js

@@ -109,6 +109,8 @@ const FORBIDDEN = [
 	/\btht\s+cte\s+plan\b/,
 	// La promozione in memoria passa dal reviewer (reviewer_memory_promote), mai da shell.
 	/\btht\s+memory\s+(promote|save-one)\b/,
+	// La re-introspezione del DWH (~3 min) è manutenzione fuori sessione, mai in workflow.
+	/\btht\s+schema\s+introspect\b[^\n]*--refresh/,
 ];
 const PROTECTED_FILES =
 	/(review_decisions\.jsonl|session_manifest\.yaml|cte_plan\.json)/;

harness/.pi/skills/tht-sessione/SKILL.md

@@ -148,10 +148,21 @@ it is complete. (The backend already refuses resume for finalized/archived sessi
 
 Prerequisite: you must already be in Phase 1.
 
+**F1 toolbox.** The only commands you need here are `tht search find` and `tht schema
+render` — both fast, read-only lookups over workspace artifacts already on disk.
+Evidence lives in `<workspace>/evidence/**` and is what `tht search find --kind evidence`
+returns — do not browse it with `find`/`cat`. Do NOT run `tht schema introspect`: it is
+a maintenance command that re-reads the remote DWH (~3 minutes); the catalog
+`artifacts/mschema/physical.yaml` is already in the workspace. Do NOT explore with
+`--help` or ad-hoc shell commands — every command you need is named in this skill.
+
 1. Explore the DWH and knowledge base: `tht search find "<term>"` (evidence + schema, LSH
    over real values) and `tht search find --kind evidence "<term>"`. The LSH exposes
    EVERY column where a value appears — it does not collapse to a single best match,
    so a value like "ablazione" may anchor on multiple columns.
+   First list ALL the ambiguous terms in the question, then run the `tht search find`
+   calls for every term in ONE batch (a single message with multiple shell invocations)
+   — not one lookup per turn.
 2. For each ambiguity (clinical term, population, time window, outcome), present the
    candidate interpretations (`recommended:true` on the best) + "Altro". Pick the widget
    by the question's shape:
@@ -230,8 +241,10 @@ Phase 3 (CLI exit 5).
 
 Prerequisite: Phase 3 closed.
 
-1. `tht schema introspect` + `tht schema render --format mschema-text` for the schema
+1. `tht schema render --format mschema-text` for the schema context (the catalog
-   context. Copy table/column names EXACTLY from it — never invent objects.
+   `artifacts/mschema/physical.yaml` is already in the workspace; only if render fails
+   with `physical.yaml non trovato`, run `tht schema introspect` once, then render).
+   Copy table/column names EXACTLY from it — never invent objects.
    Also run `tht memory solved-search "<question>" --json`: similar already-solved
    questions show which tables comparable questions used. Cite relevant precedents
    (session id + tables) to the reviewer as CONTEXT — they are reference material,

harness/tests/test_schema_introspect_guard.py

@@ -0,0 +1,70 @@
+from datetime import datetime
+
+from typer.testing import CliRunner
+
+from tht.cli import app
+from tht.mschema.models import ColumnPhysical, PhysicalSchema, TablePhysical
+
+
+def _write_catalog(tmp_path):
+    phys = PhysicalSchema(
+        database="d", schema="s", introspected_at=datetime(2026, 1, 1),
+        tables={
+            "dim_patient": TablePhysical(
+                comment="Anagrafica",
+                columns={
+                    "cod_paz": ColumnPhysical(type="bigint", pk=True, comment="Codice paziente"),
+                },
+            )
+        },
+    )
+    out = tmp_path / "artifacts" / "mschema" / "physical.yaml"
+    phys.to_yaml(out)
+    return out
+
+
+def _write_config(tmp_path):
+    cfg = tmp_path / "workspace.yaml"
+    cfg.write_text(
+        "database: {database: d, schema: s, user: u, password: p, transport: direct}\n"
+        f"paths: {{artifacts: {tmp_path/'artifacts'}, indexes: {tmp_path/'i'}, sessions: {tmp_path/'s'}}}\n"
+    )
+    return cfg
+
+
+def test_introspect_cache_hit_skips_dwh(tmp_path):
+    # Le credenziali sono fasulle: se la guardia non scattasse PRIMA del branch
+    # transport, il comando tenterebbe la connessione e fallirebbe.
+    catalog = _write_catalog(tmp_path)
+    before = catalog.read_bytes()
+    cfg = _write_config(tmp_path)
+    res = CliRunner().invoke(app, ["schema", "introspect", "-c", str(cfg)])
+    assert res.exit_code == 0, res.output
+    assert "OK (cache)" in res.output
+    assert "1 tabelle" in res.output
+    assert catalog.read_bytes() == before
+
+
+def test_introspect_refresh_bypasses_cache(tmp_path):
+    _write_catalog(tmp_path)
+    cfg = _write_config(tmp_path)
+    res = CliRunner().invoke(app, ["schema", "introspect", "-c", str(cfg), "--refresh"])
+    assert res.exit_code != 0
+    assert "OK (cache)" not in res.output
+
+
+def test_introspect_corrupt_catalog_falls_through(tmp_path):
+    catalog = tmp_path / "artifacts" / "mschema" / "physical.yaml"
+    catalog.parent.mkdir(parents=True)
+    catalog.write_text("{not: [valid")
+    cfg = _write_config(tmp_path)
+    res = CliRunner().invoke(app, ["schema", "introspect", "-c", str(cfg)])
+    assert res.exit_code != 0
+    assert "OK (cache)" not in res.output
+
+
+def test_render_without_catalog_guides_fallback(tmp_path):
+    cfg = _write_config(tmp_path)
+    res = CliRunner().invoke(app, ["schema", "render", "-c", str(cfg)])
+    assert res.exit_code == 1
+    assert "Esegui prima" in res.output

harness/tht/cli/schema_cmd.py

@@ -30,9 +30,40 @@ def annotations_path(cfg) -> Path:
 
 
 @schema_app.command("introspect")
-def introspect_cmd(config: Path = CONFIG_OPT) -> None:
+def introspect_cmd(
-    """Introspeziona lo schema target e genera artifacts/mschema/physical.yaml."""
+    config: Path = CONFIG_OPT,
+    refresh: bool = typer.Option(
+        False,
+        "--refresh",
+        help="Forza la re-introspezione del DWH anche se physical.yaml esiste già.",
+    ),
+) -> None:
+    """Introspeziona lo schema target e genera artifacts/mschema/physical.yaml.
+
+    Se physical.yaml esiste già, esce subito (cache); usa --refresh per rigenerarlo.
+    """
     cfg = _load_config_or_exit(config)
+    out = physical_path(cfg)
+    if out.exists() and not refresh:
+        from datetime import UTC, datetime
+
+        from tht.mschema.models import PhysicalSchema
+
+        try:
+            cached = PhysicalSchema.from_yaml(out)
+        except Exception:
+            pass  # catalogo illeggibile: procedi con la re-introspezione
+        else:
+            ts = cached.introspected_at
+            if ts.tzinfo is None:
+                ts = ts.replace(tzinfo=UTC)
+            age_days = (datetime.now(UTC) - ts).days
+            typer.secho(
+                f"OK (cache): {out} esistente ({len(cached.tables)} tabelle, "
+                f"età {age_days}g). Re-introspezione solo con --refresh (manutenzione).",
+                fg=typer.colors.GREEN,
+            )
+            return
     if cfg.database.transport == "rest":
         from tht.db.introspect import introspect_rest
         from tht.db.sampling import add_examples_rest
@@ -59,7 +90,6 @@ def introspect_cmd(config: Path = CONFIG_OPT) -> None:
         except (OperationalError, IntrospectionError) as e:
             typer.secho(f"ERRORE: {e}", fg=typer.colors.RED, err=True)
             raise typer.Exit(code=1)
-    out = physical_path(cfg)
     phys.to_yaml(out)
     n_cols = sum(len(t.columns) for t in phys.tables.values())
     n_ignored = sum(