feat: gate decision-type validation, force-advance, and frontend fixes

Gate (tht-gate.js):
- Pre-validate decision types against workflow.yaml before showing reviewer widget
- Reject decisions emitted by later phases (min-phase check)
- Copy top-level `kind` into artifact when model forgets it (prevents loop)
- Force-advance on reviewer_decide/schema_linking when advance:true — skip
  redundant reviewer_confirm gate

Backend:
- Emit agent_end on clean Pi exit (code 0 + bridge idle) instead of marking failed

Frontend:
- Strip <think> tags from transcript and activity panel
- Fix mermaid render with offscreen container + cleanup
- Graceful mermaid error: show source code instead of red error, fall back to table

Workflow:
- F2 now emits table_promoted and table_excluded (early schema linking decisions)

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

backend/src/pi/pi-process-manager.ts

@@ -122,6 +122,14 @@ export class PiProcessManager {
       child.on("exit", (code) => {
         console.error(`[pi:${sessionId}] exited code=${code ?? "?"} mapped=${this.runtimes.get(sessionId) === runtime}`);
         if (this.runtimes.get(sessionId) === runtime) {
+          // Clean exit (code 0) while the bridge is idle means the model completed its
+          // turn and Pi shut down normally (e.g. after session finalization). Just clean
+          // up — no failure events.
+          if (code === 0 && runtime.bridge.turnState() === "idle") {
+            this.runtimes.delete(sessionId);
+            runtime.bridge.emitClientEvent({ type: "system_event", event: "agent_end" });
+            return;
+          }
           runtime.bridge.markFailed();
           this.runtimes.delete(sessionId);
           runtime.bridge.emitClientEvent({

frontend/src/shell/CentralStatus.tsx

@@ -5,6 +5,8 @@ import { isNearBottom } from "./activityScroll";
 function transcriptLines(transcript: Array<{ text: string }>): string[] {
   return transcript.flatMap(({ text }) =>
     text
+      .replace(/<think>[\s\S]*?<\/think>/g, "")
+      .replace(/<\/?think>/g, "")
       .split("\n")
       .map((line) => line.trimEnd())
       .filter((line) => line.trim() !== ""),

frontend/src/shell/ModelActivityPanel.tsx

@@ -25,6 +25,8 @@ export function isVisibleModelActivity(entry: ActivityEntry): boolean {
 
 export function formatModelActivity(text: string): string {
   return text
+    .replace(/<think>[\s\S]*?<\/think>/g, "")
+    .replace(/<\/?think>/g, "")
     .replace(/\r\n?/g, "\n")
     .replace(/([.!?])(?=[A-ZÀ-ÖØ-Þ])/g, "$1\n\n")
     .replace(/^[\t ]*[•‣–]\s+/gm, "- ")

frontend/src/viewers/MarkdownView.tsx

@@ -16,7 +16,7 @@ function MermaidBlock({ code }: { code: string }) {
       );
   }, [code]);
 
-  if (error) return <pre className="text-destructive text-xs">{error}</pre>;
+  if (error) return <pre className="overflow-auto rounded-lg bg-muted p-3 text-xs opacity-60">{code}</pre>;
   if (!svg) return <pre className="text-xs opacity-50">{code}</pre>;
   // eslint-disable-next-line react/no-danger
   return <div dangerouslySetInnerHTML={{ __html: svg }} />;

frontend/src/viewers/SchemaLinkingViewer.tsx

@@ -116,9 +116,9 @@ export function SchemaLinkingViewer({ linking }: { linking: SchemaLinking }) {
     if (view !== "chart" || oversized) return;
     let cancelled = false;
     const def = buildErDiagram(promoted, linking.joins);
-    renderMermaid(def).then((s) => {
-      if (!cancelled) setSvg(s);
-    });
+    renderMermaid(def)
+      .then((s) => { if (!cancelled) setSvg(s); })
+      .catch(() => { if (!cancelled) setView("table"); });
     return () => {
       cancelled = true;
     };

frontend/src/viewers/mermaid.ts

@@ -7,6 +7,15 @@ export async function renderMermaid(def: string): Promise<string> {
     _initialized = true;
   }
   const id = `mermaid-${Math.random().toString(36).slice(2)}`;
-  const { svg } = await mermaid.render(id, def);
-  return svg;
+  const container = document.createElement("div");
+  container.style.position = "absolute";
+  container.style.left = "-9999px";
+  document.body.appendChild(container);
+  try {
+    const { svg } = await mermaid.render(id, def, container);
+    return svg;
+  } finally {
+    container.remove();
+    document.getElementById(id)?.remove();
+  }
 }

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

@@ -129,6 +129,11 @@ export function prepareReviewerArguments(input) {
 	if (args.artifact && typeof args.artifact === "object" && args.artifact.data !== undefined) {
 		args.artifact = { ...args.artifact, data: jsonObjectOrSelf(args.artifact.data) };
 	}
+	// Models frequently forget artifact.kind while providing it at top level —
+	// copy it over so validation doesn't loop.
+	if (args.artifact && typeof args.artifact === "object" && !args.artifact.kind && args.kind) {
+		args.artifact = { ...args.artifact, kind: args.kind };
+	}
 	return args;
 }
 
@@ -275,6 +280,52 @@ function phaseId(ctx, num) {
 	const p = meta.phases.find((x) => x.num === num);
 	return p ? p.id : "?";
 }
+// Known decision types from workflow.yaml emits + meta types. Pre-validates decision
+// payloads BEFORE showing the reviewer widget so a typo in the type name doesn't waste
+// a human interaction (the CLI would reject it only after the reviewer has already picked).
+let _knownTypes = null;
+function knownDecisionTypes(ctx) {
+	if (_knownTypes) return _knownTypes;
+	const meta = phaseMeta(ctx);
+	const types = new Set([
+		"phase_approved", "phase_auto_approved", "phase_reopened",
+		"phase_skipped", "decision_retracted",
+	]);
+	for (const p of meta.phases) {
+		for (const t of (p.emits || [])) types.add(t);
+	}
+	_knownTypes = types;
+	return types;
+}
+function decisionMinPhaseMap(ctx) {
+	const meta = phaseMeta(ctx);
+	const mins = {};
+	for (const p of meta.phases) {
+		for (const t of (p.emits || [])) {
+			if (!(t in mins) || p.num < mins[t]) mins[t] = p.num;
+		}
+	}
+	return mins;
+}
+function validateDecisionTypes(ctx, options, session) {
+	const known = knownDecisionTypes(ctx);
+	for (const o of options) {
+		if (o.decision && !known.has(o.decision.type)) {
+			return `Tipo di decisione '${o.decision.type}' non valido. Tipi ammessi: ${[...known].join(", ")}. Correggi e riprova.`;
+		}
+	}
+	if (session) {
+		const cur = currentPhase(ctx, session);
+		const mins = decisionMinPhaseMap(ctx);
+		for (const o of options) {
+			if (o.decision && mins[o.decision.type] && mins[o.decision.type] > cur) {
+				return `Tipo '${o.decision.type}' ammesso dalla Fase ${mins[o.decision.type]}, sessione alla Fase ${cur}. Chiudi prima la fase corrente.`;
+			}
+		}
+	}
+	return null;
+}
+
 // Full phase descriptor {id, num, name} for the v2 phase-summary payload's `phase`.
 function phaseMetaForNum(ctx, num) {
 	const meta = phaseMeta(ctx);
@@ -316,6 +367,21 @@ function advanceIfReady(ctx, session) {
 	}
 }
 
+// Unconditional phase advance — the reviewer already approved via the widget interaction
+// (reviewer_decide selection IS the human confirmation). Used when reviewer_decide persists
+// substantive decisions with advance:true, so no separate reviewer_confirm gate is needed.
+function forceAdvance(ctx, session) {
+	try {
+		tht(ctx, ["phase", "advance", "--session", session]);
+		return { advanced: true };
+	} catch (e) {
+		return {
+			advanced: false,
+			error: (e.stderr || e.message || String(e)).toString().trim(),
+		};
+	}
+}
+
 // --- widget emission + wait — usa l'API UI NATIVA di Pi (ctx.ui.input) --------
 //
 // emitAndWait(ctx, descriptor) sends the widget-descriptor as JSON in the `title`
@@ -662,6 +728,8 @@ export default function (pi) {
 		async execute(_id, params, _signal, _onUpdate, ctx) {
 			lockActive = true;
 			const { session, title, options: opts, intro, advance } = params;
+			const typeErr = validateDecisionTypes(ctx, opts, session);
+			if (typeErr) return textResult(typeErr);
 			const phase = phaseId(ctx, currentPhase(ctx, session));
 			const recommended = opts.find((o) => o.recommended)?.id ?? null;
 
@@ -734,6 +802,8 @@ export default function (pi) {
 		async execute(_id, params, _signal, _onUpdate, ctx) {
 			lockActive = true;
 			const { session, title, options: opts, advance } = params;
+			const typeErr = validateDecisionTypes(ctx, opts, session);
+			if (typeErr) return textResult(typeErr);
 			const phase = phaseId(ctx, currentPhase(ctx, session));
 			const toAdd = [];
 			const meritOptions = opts
@@ -813,12 +883,17 @@ export default function (pi) {
 					toAdd.push(d);
 				}
 			}
-			if (advance) advanceIfReady(ctx, session);
-			return textResult(
-				toAdd.length
-					? `Registrate ${toAdd.length} decisioni: ${toAdd.map((d) => d.type).join(", ")}.`
-					: "Nessuna decisione registrata (il reviewer non ha selezionato opzioni di merito).",
-			);
+			if (!toAdd.length) {
+				const adv = advance ? advanceIfReady(ctx, session) : { advanced: false };
+				const msg = "Nessuna decisione registrata (il reviewer non ha selezionato opzioni di merito).";
+				return textResult(adv.advanced ? msg + " Fase avanzata automaticamente." : msg);
+			}
+			// Decisions were recorded AND advance requested: the reviewer's selection IS the
+			// approval — force-advance without a separate reviewer_confirm gate.
+			const adv = advance ? forceAdvance(ctx, session) : { advanced: false };
+			const parts = [`Registrate ${toAdd.length} decisioni: ${toAdd.map((d) => d.type).join(", ")}.`];
+			if (adv.advanced) parts.push("Fase avanzata automaticamente — nessun gate aggiuntivo necessario.");
+			return textResult(parts.join(" "));
 		},
 	});
 
@@ -924,8 +999,10 @@ export default function (pi) {
 			const eSync = relayIfThtFails(ctx, ["session", "sync-schema-linking", session], "");
 			if (eSync) return eSync;
 
-			if (advance) advanceIfReady(ctx, session);
-			return textResult(`Schema linking registrato dal reviewer (${n} tabelle + colonne curate).`);
+			const adv = advance ? forceAdvance(ctx, session) : { advanced: false };
+			const parts = [`Schema linking registrato dal reviewer (${n} tabelle + colonne curate). schema_linking.json scritto.`];
+			if (adv.advanced) parts.push("Fase avanzata automaticamente — nessun gate aggiuntivo necessario.");
+			return textResult(parts.join(" "));
 		},
 	});
 

harness/tests/test_decision_min_phase.py

@@ -16,7 +16,7 @@ from tht.workflow import load_workflow
         ("concept_clarified", 1),
         ("memory_rejected", 2),
         ("question_rewritten", 3),
-        ("table_promoted", 4),
+        ("table_promoted", 2),
         ("column_corrected", 4),
         ("evidence_accepted", 4),
         ("value_grounded", 4),

harness/workflow.yaml

@@ -21,7 +21,7 @@ phases:
     advance: auto_if_empty
     prerequisites: []
     artifacts_out: []
-    emits: [memory_rejected]
+    emits: [memory_rejected, table_promoted, table_excluded]
   - id: F3
     name: riscrittura
     advance: kind:phase