fix(gate): auto-finalize session after last phase approval

The model sometimes stops after receiving 'Fase approvata' without calling
`tht session finalize`, leaving the session open. Now the gate itself calls
finalize after advancing the max phase (F8), making session closure
deterministic regardless of model behavior.

- reviewer_confirm kind:phase: after phase advance at max_phase, gate calls
  `tht session finalize <session>` (best-effort with recovery message)
- SKILL.md updated: model no longer needs to call finalize itself
- Tests: 2 new JS tests (auto-finalize at max phase; no-finalize at non-max)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

harness/.pi/extensions/gate/__tests__/gate_confirm_cte_v2.test.js

@@ -345,9 +345,11 @@ test("reviewer_confirm kind:phase (v2): fills phase from phaseMeta and enriches
   const origExecFileSync = cp.execFileSync;
   cp.execFileSync = (file, args) => {
     if (args[0] === "phase" && args[1] === "meta")
-      return JSON.stringify({ phases: [{ num: 5, id: "F5", name: "sintesi" }] });
+      return JSON.stringify({ max_phase: 8, phases: [{ num: 5, id: "F5", name: "sintesi", emits: [] }] });
     if (args[0] === "phase" && args[1] === "show") return "Fase corrente: 5\n";
     if (args[0] === "phase" && args[1] === "advance") return "";
+    if (args[0] === "session" && args[1] === "show")
+      return JSON.stringify({ decisions: [] });
     if (args[0] === "schema" && args[1] === "columns")
       return JSON.stringify(CATALOG[args[2]] || {});
     return "";
@@ -386,11 +388,83 @@ test("reviewer_confirm kind:phase (v2): fills phase from phaseMeta and enriches
   }
 });
 
+test("reviewer_confirm kind:phase (v2) at max_phase auto-finalizes the session", async () => {
+  const origExecFileSync = cp.execFileSync;
+  let finalizeCalled = false;
+  cp.execFileSync = (file, args) => {
+    if (args[0] === "phase" && args[1] === "meta")
+      return JSON.stringify({ max_phase: 8, phases: [{ num: 8, id: "F8", name: "datamart", emits: [] }] });
+    if (args[0] === "phase" && args[1] === "show") return "Fase corrente: 8\n";
+    if (args[0] === "phase" && args[1] === "advance") return "";
+    if (args[0] === "session" && args[1] === "show")
+      return JSON.stringify({ decisions: [] });
+    if (args[0] === "session" && args[1] === "finalize") { finalizeCalled = true; return ""; }
+    return "";
+  };
+  try {
+    const { ctx, tools } = await loadGate();
+    ctx.ui.input = async (title) => {
+      const d = JSON.parse(title);
+      return JSON.stringify({ id: d.id, choices: ["approve"] });
+    };
+    const tool = tools.get("reviewer_confirm");
+    const result = await tool.def.execute(
+      "call-1",
+      {
+        session: "s1", kind: "phase", title: "Chiusura F8",
+        artifact: { kind: "phase", data: { schema_version: 2, summary: "done" } },
+      },
+      null, null, ctx,
+    );
+    assert.ok(finalizeCalled, "gate must auto-finalize after last phase advance");
+    assert.match(result.content[0].text, /finalizzata/);
+  } finally {
+    cp.execFileSync = origExecFileSync;
+  }
+});
+
+test("reviewer_confirm kind:phase at non-max phase does NOT finalize", async () => {
+  const origExecFileSync = cp.execFileSync;
+  let finalizeCalled = false;
+  cp.execFileSync = (file, args) => {
+    if (args[0] === "phase" && args[1] === "meta")
+      return JSON.stringify({ max_phase: 8, phases: [{ num: 5, id: "F5", name: "sintesi", emits: [] }] });
+    if (args[0] === "phase" && args[1] === "show") return "Fase corrente: 5\n";
+    if (args[0] === "phase" && args[1] === "advance") return "";
+    if (args[0] === "session" && args[1] === "show")
+      return JSON.stringify({ decisions: [] });
+    if (args[0] === "session" && args[1] === "finalize") { finalizeCalled = true; return ""; }
+    if (args[0] === "schema" && args[1] === "columns") return "{}";
+    return "";
+  };
+  try {
+    const { ctx, tools } = await loadGate();
+    ctx.ui.input = async (title) => {
+      const d = JSON.parse(title);
+      return JSON.stringify({ id: d.id, choices: ["approve"] });
+    };
+    const tool = tools.get("reviewer_confirm");
+    const result = await tool.def.execute(
+      "call-1",
+      {
+        session: "s1", kind: "phase", title: "Chiusura F5",
+        artifact: { kind: "phase", data: { schema_version: 2, summary: "ok" } },
+      },
+      null, null, ctx,
+    );
+    assert.ok(!finalizeCalled, "must NOT finalize at non-max phase");
+    assert.match(result.content[0].text, /Fase approvata/);
+    assert.ok(!result.content[0].text.includes("finalizzata"));
+  } finally {
+    cp.execFileSync = origExecFileSync;
+  }
+});
+
 test("reviewer_confirm kind:phase legacy (non-v2 data): unchanged path", async () => {
   const origExecFileSync = cp.execFileSync;
   cp.execFileSync = (file, args) => {
     if (args[0] === "phase" && args[1] === "meta")
-      return JSON.stringify({ phases: [{ num: 1, id: "F1", name: "chiarimento" }] });
+      return JSON.stringify({ max_phase: 8, phases: [{ num: 1, id: "F1", name: "chiarimento" }] });
     if (args[0] === "phase" && args[1] === "show") return "Fase corrente: 1\n";
     if (args[0] === "phase" && args[1] === "advance") return "";
     return "";

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

@@ -957,6 +957,23 @@ export default function (pi) {
 					PHASE_RECOVERY,
 				);
 				if (err) return err;
+				// Auto-finalize after advancing the LAST phase: the model may not
+				// follow through (token budget, turn end) leaving the session open.
+				const meta = phaseMeta(ctx);
+				if (curNum >= meta.max_phase) {
+					const fErr = relayIfThtFails(
+						ctx,
+						["session", "finalize", session],
+						"Fase approvata ma finalizzazione fallita: esegui manualmente " +
+							`\`tht session finalize ${session}\`.`,
+					);
+					if (fErr) return fErr;
+					lockActive = false;
+					lastSteered = false;
+					return textResult(
+						`Fase ${curNum} approvata e sessione finalizzata (${session}).`,
+					);
+				}
 				return textResult(`Fase approvata (sessione ${session}).`);
 			}
 			if (kind === "cte_plan") {

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

@@ -393,12 +393,14 @@ Prerequisite: Phase 7 closed.
    pre-selected checklist. Selected → saved to the vectordb + `memory_promoted`;
    deselected → `memory_promotion_declined` (never re-proposed). If the gate reports
    zero candidates, move on — do not retry.
-4. Close with `reviewer_confirm kind:"phase"`. The session is finalizable.
+4. Close with `reviewer_confirm kind:"phase"`. The gate auto-finalizes the session
+   after advancing the last phase — you do NOT need to call `tht session finalize`
+   yourself. If auto-finalize fails, the error message tells you the recovery command.
 
 ## Session end
 
-When the workflow is complete (Phase 8), `tht session finalize` closes the session
-and unlocks input. Finalize also indexes the question→SQL pair in the vectordb
-(kind `solved_question`, best-effort — on failure recover with `tht memory
-solved-index <id>`). The persisted state (ledger `review_decisions.jsonl` +
-artifacts) is the truth: what is not recorded did not happen.
+When Phase 8 is approved, the gate calls `tht session finalize` automatically.
+Finalize also indexes the question→SQL pair in the vectordb (kind `solved_question`,
+best-effort — on failure recover with `tht memory solved-index <id>`). The persisted
+state (ledger `review_decisions.jsonl` + artifacts) is the truth: what is not
+recorded did not happen.