diff --git a/harness/.pi/extensions/tht-gate.js b/harness/.pi/extensions/tht-gate.js
index d5001d0c..1a159930 100644
--- a/harness/.pi/extensions/tht-gate.js
+++ b/harness/.pi/extensions/tht-gate.js
@@ -30,7 +30,32 @@ import {
 	buildMultiselectRequest,
 	buildArtifactGate,
 } from "./gate/builders.js";
-import { isReserved, stripReserved } from "./reserved-labels.mjs";
+import { isReserved } from "./reserved-labels.mjs";
+
+// --- prepareArguments: parse stringified arrays (workaround for models that send
+//    arrays as JSON strings -- same pattern as pi-core's edit tool prepareEditArguments)
+function prepareReviewerArguments(input) {
+	if (!input || typeof input !== "object") return input;
+	const args = { ...input };
+	// Parse stringified JSON arrays (workaround for models that send arrays as strings)
+	if (typeof args.options === "string") {
+		try {
+			const parsed = JSON.parse(args.options);
+			if (Array.isArray(parsed)) args.options = parsed;
+		} catch {
+			/* not JSON */
+		}
+	}
+	if (typeof args.names === "string") {
+		try {
+			const parsed = JSON.parse(args.names);
+			if (Array.isArray(parsed)) args.names = parsed;
+		} catch {
+			/* not JSON */
+		}
+	}
+	return args;
+}
 
 // --- anti-bypass block lists (spec D4, verbatim from source L169-177) -----------
 const FORBIDDEN = [
@@ -38,7 +63,8 @@ const FORBIDDEN = [
 	/\btht\s+decision\s+add\b/,
 	/\btht\s+cte\s+plan\b/,
 ];
-const PROTECTED_FILES = /(review_decisions\.jsonl|session_manifest\.yaml|cte_plan\.json)/;
+const PROTECTED_FILES =
+	/(review_decisions\.jsonl|session_manifest\.yaml|cte_plan\.json)/;
 
 // --- kickoff payloads (verbatim from source L184-212, load-bearing model prose) -
 const NUOVA_DOMANDA_KICKOFF =
@@ -82,7 +108,8 @@ const RIPRENDI_KICKOFF =
 	"reviewer_*, niente phase advance/reopen o decision add da shell, una fase alla volta.";
 
 // Recovery hint shown when `tht phase advance` refuses with exit 5 (gate not satisfied).
-const PHASE_RECOVERY = "Completa i prerequisiti della fase (decisioni/artefatti) e riprova.";
+const PHASE_RECOVERY =
+	"Completa i prerequisiti della fase (decisioni/artefatti) e riprova.";
 
 // --- helpers (verbatim from source) -------------------------------------------
 
@@ -90,8 +117,32 @@ function textResult(text) {
 	return { content: [{ type: "text", text }], details: {} };
 }
 
+// Load THT_* env vars from .env (project root = ctx.cwd).
+function loadEnvFromDotenv(ctx) {
+	const fs = require("node:fs");
+	const path = require("node:path");
+	const envPath = path.join(ctx.cwd, ".env");
+	try {
+		const raw = fs.readFileSync(envPath, "utf8");
+		for (const line of raw.split("\n")) {
+			const trimmed = line.trim();
+			if (!trimmed || trimmed.startsWith("#")) continue;
+			const idx = trimmed.indexOf("=");
+			if (idx === -1) continue;
+			const key = trimmed.slice(0, idx).trim();
+			const value = trimmed.slice(idx + 1).trim();
+			if (key.startsWith("THT_") || key.startsWith("PSD_")) {
+				process.env[key] = value;
+			}
+		}
+	} catch {
+		// .env not found or unreadable — proceed with existing env.
+	}
+}
+
 // Single chokepoint for all CLI calls. cwd is the Pi project root (harness/).
 function tht(ctx, args) {
+	loadEnvFromDotenv(ctx);
 	return execFileSync("tht", args, { cwd: ctx.cwd, encoding: "utf8" });
 }
 
@@ -139,7 +190,10 @@ function advanceIfReady(ctx, session) {
 		return { advanced: true };
 	} catch (e) {
 		if (e.status === 6) return { advanced: false };
-		return { advanced: false, error: (e.stderr || e.message || String(e)).toString().trim() };
+		return {
+			advanced: false,
+			error: (e.stderr || e.message || String(e)).toString().trim(),
+		};
 	}
 }
 
@@ -156,17 +210,29 @@ function advanceIfReady(ctx, session) {
 export async function emitAndWait(ctx, descriptor) {
 	for (;;) {
 		const value = await ctx.ui.input(JSON.stringify(descriptor), "");
-		if (value === undefined || value === null) { await reLoop(ctx); continue; }
+		if (value === undefined || value === null) {
+			await reLoop(ctx);
+			continue;
+		}
 		let resp;
-		try { resp = JSON.parse(value); } catch { await reLoop(ctx); continue; }
-		if (resp && resp.control !== "cancel" && resp.id === descriptor.id) return resp;
+		try {
+			resp = JSON.parse(value);
+		} catch {
+			await reLoop(ctx);
+			continue;
+		}
+		if (resp && resp.control !== "cancel" && resp.id === descriptor.id)
+			return resp;
 		await reLoop(ctx);
 	}
 }
 
 async function reLoop(ctx) {
-	if (ctx.hasUI) await ctx.ui.notify(
-		"Esc non chiude il gate: usa Torna indietro / Esci / Altro dalle opzioni.", "warning");
+	if (ctx.hasUI)
+		await ctx.ui.notify(
+			"Esc non chiude il gate: usa Torna indietro / Esci / Altro dalle opzioni.",
+			"warning",
+		);
 }
 
 // --- the extension ------------------------------------------------------------
@@ -202,7 +268,8 @@ export default function (pi) {
 			if (PROTECTED_FILES.test(path)) {
 				return {
 					block: true,
-					reason: "Questo file di stato e' gestito dal gate: non scriverlo direttamente.",
+					reason:
+						"Questo file di stato e' gestito dal gate: non scriverlo direttamente.",
 				};
 			}
 		}
@@ -218,9 +285,9 @@ export default function (pi) {
 			lockActive = true;
 			lastSteered = false;
 			pendingKickoff = /^\/nuova-domanda\b/.test(raw)
-				? (process.env.THT_SESSION
+				? process.env.THT_SESSION
 					? NUOVA_DOMANDA_KICKOFF_PROVIDED(process.env.THT_SESSION)
-					: NUOVA_DOMANDA_KICKOFF)
+					: NUOVA_DOMANDA_KICKOFF
 				: RIPRENDI_KICKOFF;
 		}
 		// free-input block: attivo quando il lock è su, per qualsiasi input utente (non solo interattivo).
@@ -229,7 +296,8 @@ export default function (pi) {
 		if (trimmed.length === 0) return { action: "continue" };
 		if (trimmed.startsWith("/")) return { action: "continue" };
 		// `!`-prefixed free text -> forward to the model (the one sanctioned steer channel).
-		if (trimmed.startsWith("!")) return { action: "transform", text: trimmed.slice(1).trimStart() };
+		if (trimmed.startsWith("!"))
+			return { action: "transform", text: trimmed.slice(1).trimStart() };
 		if (ctx.hasUI) {
 			await ctx.ui.notify(
 				"Durante la sessione rispondi con i widget del gate. " +
@@ -268,7 +336,9 @@ export default function (pi) {
 			last &&
 			last.role === "assistant" &&
 			Array.isArray(last.content) &&
-			last.content.some((b) => b.type === "text" && (b.text ?? "").trim().length > 0) &&
+			last.content.some(
+				(b) => b.type === "text" && (b.text ?? "").trim().length > 0,
+			) &&
 			!last.content.some((b) => b.type === "toolCall");
 		if (isProse && !lastSteered) {
 			lastSteered = true;
@@ -290,7 +360,9 @@ export default function (pi) {
 			"controllo (Altro/Torna indietro/Esci) sono sempre presenti. NON persiste: serve a " +
 			"chiedere, non a decidere.",
 		parameters: Type.Object({
-			session: Type.String({ description: "Id sessione (per determinare la fase)." }),
+			session: Type.String({
+				description: "Id sessione (per determinare la fase).",
+			}),
 			title: Type.String(),
 			options: Type.Array(
 				Type.Object({
@@ -301,27 +373,35 @@ export default function (pi) {
 			),
 			intro: Type.Optional(Type.String()),
 		}),
+		prepareArguments: prepareReviewerArguments,
 		async execute(_id, params, _signal, _onUpdate, ctx) {
 			lockActive = true;
 			const { session, title, options: opts, intro } = params;
 			const phase = phaseName(ctx, currentPhase(ctx, session));
 			const recommended = opts.find((o) => o.recommended)?.id ?? null;
-			const clean = stripReserved(opts.map((o) => o.label));
+
 			const widget = buildSelectRequest({
 				id: `u${Date.now()}`,
 				phase,
 				title,
 				intro: intro ?? null,
 				recommended,
-				options: opts.filter((o) => !isReserved(o.label)).map((o) => ({ id: o.id, label: o.label })),
+				options: opts
+					.filter((o) => !isReserved(o.label))
+					.map((o) => ({ id: o.id, label: o.label })),
 			});
 			const resp = await emitAndWait(ctx, widget);
 			// control responses (back/exit/other) are surfaced as text for the model to act on.
-			if (resp.control === "freetext") return textResult(`Altro (reviewer): ${resp.text}`);
-			if (resp.control === "back") return textResult("Il reviewer vuole tornare indietro.");
-			if (resp.control === "exit") return textResult("Il reviewer vuole uscire.");
+			if (resp.control === "freetext")
+				return textResult(`Altro (reviewer): ${resp.text}`);
+			if (resp.control === "back")
+				return textResult("Il reviewer vuole tornare indietro.");
+			if (resp.control === "exit")
+				return textResult("Il reviewer vuole uscire.");
 			const chosen = opts.find((o) => o.id === resp.choice);
-			return textResult(`Scelta del reviewer: ${chosen ? chosen.label : resp.choice}`);
+			return textResult(
+				`Scelta del reviewer: ${chosen ? chosen.label : resp.choice}`,
+			);
 		},
 	});
 
@@ -351,6 +431,7 @@ export default function (pi) {
 			allow_empty: Type.Optional(Type.Boolean()),
 			advance: Type.Optional(Type.Boolean()),
 		}),
+		prepareArguments: prepareReviewerArguments,
 		async execute(_id, params, _signal, _onUpdate, ctx) {
 			lockActive = true;
 			const { session, title, options: opts, advance } = params;
@@ -361,20 +442,34 @@ export default function (pi) {
 				phase,
 				title,
 				allowEmpty: params.allow_empty ?? false,
-				options: opts.filter((o) => !isReserved(o.label)).map((o) => ({ id: o.id, label: o.label })),
+				options: opts
+					.filter((o) => !isReserved(o.label))
+					.map((o) => ({ id: o.id, label: o.label })),
 				recommended: opts.find((o) => o.recommended)?.id ?? null,
 			});
 			const resp = await emitAndWait(ctx, widget);
 			if (resp.control === "freetext") {
-				return textResult(`Altro (reviewer): ${resp.text}. Riformula la proposta tenendo conto.`);
+				return textResult(
+					`Altro (reviewer): ${resp.text}. Riformula la proposta tenendo conto.`,
+				);
 			}
-			if (resp.control === "back") return textResult("Il reviewer vuole tornare indietro.");
-			if (resp.control === "exit") return textResult("Il reviewer vuole uscire.");
+			if (resp.control === "back")
+				return textResult("Il reviewer vuole tornare indietro.");
+			if (resp.control === "exit")
+				return textResult("Il reviewer vuole uscire.");
 			const chosen = opts.filter((o) => (resp.choices ?? []).includes(o.id));
 			for (const c of chosen) {
 				const d = c.decision;
-				const args = ["decision", "add", "--session", session, "--type", d.type,
-					"--subject", d.subject];
+				const args = [
+					"decision",
+					"add",
+					"--session",
+					session,
+					"--type",
+					d.type,
+					"--subject",
+					d.subject,
+				];
 				if (d.detail) args.push("--detail", d.detail);
 				if (d.rationale) args.push("--rationale", d.rationale);
 				const err = relayIfThtFails(ctx, args, "");
@@ -414,6 +509,7 @@ export default function (pi) {
 			// kind:"cte_plan" only -- ordered list of CTE names to persist (tht cte plan --name).
 			names: Type.Optional(Type.Array(Type.String())),
 		}),
+		prepareArguments: prepareReviewerArguments,
 		async execute(_id, params, _signal, _onUpdate, ctx) {
 			lockActive = true;
 			const { session, kind, title, artifact } = params;
@@ -431,14 +527,20 @@ export default function (pi) {
 					`Rifiutato${resp.text ? ` (motivo: ${resp.text})` : ""}: rivedi e riprova.`,
 				);
 			}
-			if (resp.control === "back") return textResult("Il reviewer vuole tornare indietro.");
-			if (resp.control === "exit") return textResult("Il reviewer vuole uscire.");
+			if (resp.control === "back")
+				return textResult("Il reviewer vuole tornare indietro.");
+			if (resp.control === "exit")
+				return textResult("Il reviewer vuole uscire.");
 			// approved -> execute the privileged action via the CLI.
 			if (kind === "phase") {
 				// Explicit human approval: advance unconditionally except for unmet
 				// prerequisites. Plain `phase advance` (no --auto) enforces advance_problems
 				// and exits 6 with the missing items, which relayIfThtFails surfaces.
-				const err = relayIfThtFails(ctx, ["phase", "advance", "--session", session], PHASE_RECOVERY);
+				const err = relayIfThtFails(
+					ctx,
+					["phase", "advance", "--session", session],
+					PHASE_RECOVERY,
+				);
 				if (err) return err;
 				return textResult(`Fase approvata (sessione ${session}).`);
 			}
@@ -456,13 +558,24 @@ export default function (pi) {
 				for (const n of names) planArgs.push("--name", n);
 				const err = relayIfThtFails(ctx, planArgs, "");
 				if (err) return err;
-				return textResult(`CTE plan approvato (${names.length} CTE, sessione ${session}).`);
+				return textResult(
+					`CTE plan approvato (${names.length} CTE, sessione ${session}).`,
+				);
 			}
 			if (kind === "cte_result" || kind === "sql") {
 				const dt = kind === "sql" ? "sql_approved" : "cte_approved";
 				const err = relayIfThtFails(
 					ctx,
-					["decision", "add", "--session", session, "--type", dt, "--subject", `phase:${currentPhase(ctx, session)}`],
+					[
+						"decision",
+						"add",
+						"--session",
+						session,
+						"--type",
+						dt,
+						"--subject",
+						`phase:${currentPhase(ctx, session)}`,
+					],
 					"",
 				);
 				if (err) return err;
@@ -509,11 +622,16 @@ export default function (pi) {
 
 	// --- slash command: /torna [session_id] [N] (rollback to a previous phase) --
 	pi.registerCommand("torna", {
-		description: "Torna a una fase precedente: /torna <session_id> [N] (default: un passo).",
+		description:
+			"Torna a una fase precedente: /torna <session_id> [N] (default: un passo).",
 		handler: async (args, ctx) => {
 			const parts = args.trim().split(/\s+/).filter(Boolean);
 			const sessionId =
-				parts.length >= 2 ? parts[0] : parts.length === 1 && /^\d/.test(parts[0]) ? undefined : parts[0];
+				parts.length >= 2
+					? parts[0]
+					: parts.length === 1 && /^\d/.test(parts[0])
+						? undefined
+						: parts[0];
 			const sid = sessionId ?? activeSessionId ?? process.env.THT_SESSION;
 			if (!sid) {
 				await ctx.ui.notify("Uso: /torna <session_id> [N]", "warning");
@@ -523,10 +641,20 @@ export default function (pi) {
 			const targetArg = parts.find((x) => /^\d+$/.test(x));
 			const target = targetArg ? parseInt(targetArg, 10) : cur - 1;
 			if (target < 1 || target >= cur) {
-				await ctx.ui.notify(`Target non valido (fase corrente ${cur}).`, "warning");
+				await ctx.ui.notify(
+					`Target non valido (fase corrente ${cur}).`,
+					"warning",
+				);
 				return;
 			}
-			tht(ctx, ["phase", "reopen", "--session", sid, "--phase", String(target)]);
+			tht(ctx, [
+				"phase",
+				"reopen",
+				"--session",
+				sid,
+				"--phase",
+				String(target),
+			]);
 			await pi.sendUserMessage(
 				`Ho riaperto la Fase ${target} della sessione ${sid}. Riprendi il protocollo da quella fase.`,
 				{ deliverAs: "followUp" },