diff --git a/PROJECT_STATE.md b/PROJECT_STATE.md
index ff04c353..226d80b6 100644
--- a/PROJECT_STATE.md
+++ b/PROJECT_STATE.md
@@ -1,5 +1,24 @@
 # ThothII — Project State
 
+## Modular workflow refactor candidate — live (2026-08-24)
+
+- **Isolation:** worktree `.worktrees/refactoring-modulare-contract-baseline`, branch
+  `codex/refactoring-modulare-contract-baseline`; the base stack is unchanged.
+- **Candidate runtime:** Compose project `thothii-d811484ae2e4` is healthy at frontend
+  `127.0.0.1:18080`, core `127.0.0.1:18787`, and Qdrant `127.0.0.1:16333`. Its explicit volumes
+  preserve the PSD sessions, schema index, and embedding cache across image rebuilds.
+- **Real data:** the VPN-backed PSD DWH is reachable; preprocessing indexed 163 tables and 2275
+  columns. Manual session `85a0b758-ae30-432e-8298-837bf55abad9` completed F1-F8 on the modular
+  image and finalized successfully.
+- **Phase progress fix:** Pi now emits a deduplicated, machine-readable phase-start notification
+  after persisted workflow mutations; the backend sanitizes it to `phase_started`; the frontend
+  advances the active workflow dot without waiting for a human widget. The real Pi RPC probe
+  emitted F8, and the harness/backend/frontend contract suites plus both TypeScript builds pass.
+- **Testing:** the automated probe session `cccbee8c-b13d-4bcb-88a6-aa60a4cae533` is closed at F8
+  after repeated cold-Resume probes preserved its 29 decisions and SQL/CTE/schema artifacts, so it
+  does not occupy the admin principal. The candidate stack is intentionally left running for owner
+  validation at `http://127.0.0.1:18080/`.
+
 > Starting-point snapshot for new sessions.
 > **Requisito finale del progetto (owner, 2026-08-11):** al termine dell'ultima fase tecnica deve
 > essere prodotto un documento unico che guidi l'utente passo-passo su (1) come preparare il
diff --git a/backend/src/bridge/session-bridge.ts b/backend/src/bridge/session-bridge.ts
index f1dbf2c2..69ea9559 100644
--- a/backend/src/bridge/session-bridge.ts
+++ b/backend/src/bridge/session-bridge.ts
@@ -4,6 +4,15 @@ const GENERIC_MODEL_FAILURE =
   "Model request failed. Check provider connectivity, then Resume the session.";
 const SUBSCRIPTION_MODEL_FAILURE =
   "The selected model is unavailable for the current subscription. Choose another model and start a new session.";
+const PHASE_STARTED_NOTIFICATION_PREFIX = "__tht_phase_started__:";
+
+function phaseStartedNotification(message: unknown): string | null {
+  if (typeof message !== "string" || !message.startsWith(PHASE_STARTED_NOTIFICATION_PREFIX)) {
+    return null;
+  }
+  const phase = message.slice(PHASE_STARTED_NOTIFICATION_PREFIX.length);
+  return /^F[1-8]$/.test(phase) ? phase : "";
+}
 
 function safeModelFailure(error: unknown): string {
   const detail = typeof error === "string" ? error : "";
@@ -36,7 +45,7 @@ export type ClientEvent =
   | { type: "activity_event"; activity: ToolActivity }
   | { type: "usage"; usage: TokenUsage }
   | { type: "info"; [k: string]: any }
-  | { type: "system_event"; event: string };
+  | { type: "system_event"; event: string; phase?: string };
 
 export type TurnState = "idle" | "running" | "waiting" | "failed";
 
@@ -71,7 +80,11 @@ export class SessionBridge {
           });
         }
       } else if (m.type === "extension_ui_request" && m.method === "notify") {
-        this.fan({ type: "info", level: m.notifyType ?? "info", text: m.message ?? "" });
+        const phase = phaseStartedNotification(m.message);
+        if (phase) this.fan({ type: "system_event", event: "phase_started", phase });
+        else if (phase === null) {
+          this.fan({ type: "info", level: m.notifyType ?? "info", text: m.message ?? "" });
+        }
       } else if (m.type === "message_update" && m.assistantMessageEvent?.type === "text_delta") {
         this.fan({ type: "text_delta", text: m.assistantMessageEvent.delta ?? "" });
       } else if (m.type === "message_update" && m.assistantMessageEvent?.type === "thinking_delta") {
diff --git a/backend/test/session-bridge.test.ts b/backend/test/session-bridge.test.ts
index f0a41341..87637866 100644
--- a/backend/test/session-bridge.test.ts
+++ b/backend/test/session-bridge.test.ts
@@ -42,6 +42,29 @@ test("real Pi thinking_delta becomes a dedicated activity_delta to the FE", () =
   expect(seen).toEqual([{ type: "activity_delta", text: "Valuto le ambiguità" }]);
 });
 
+test("a reserved phase notification becomes a structured phase_started event", () => {
+  const { rpc, fire } = fakeRpc();
+  const bridge = new SessionBridge(rpc);
+  const seen: any[] = [];
+  bridge.onClientEvent((event) => seen.push(event));
+
+  fire({
+    type: "extension_ui_request",
+    method: "notify",
+    notifyType: "info",
+    message: "__tht_phase_started__:F2",
+  });
+  fire({
+    type: "extension_ui_request",
+    method: "notify",
+    notifyType: "info",
+    message: "__tht_phase_started__:F9_DO_NOT_FORWARD",
+  });
+
+  expect(seen).toEqual([{ type: "system_event", event: "phase_started", phase: "F2" }]);
+  expect(JSON.stringify(seen)).not.toContain("DO_NOT_FORWARD");
+});
+
 test("assistant message_end exposes sanitized token usage with the configured context window", () => {
   const { rpc, fire } = fakeRpc();
   const bridge = new SessionBridge(rpc);
diff --git a/docs/contracts/workflow-observable-baseline.md b/docs/contracts/workflow-observable-baseline.md
index 72be860d..c201e64a 100644
--- a/docs/contracts/workflow-observable-baseline.md
+++ b/docs/contracts/workflow-observable-baseline.md
@@ -24,6 +24,7 @@ The gate suite fixes:
 - F3 rewritten question and assumptions, including mutation failure ordering;
 - F4 Evidence used, accepted, rejected, and legacy-without-corpus projections;
 - F8 Memory promotion accepted, declined, and absent, including mutation failure ordering;
+- a newly folded phase is announced once in RPC mode even when it requires no human gate;
 - resume reconstruction for the touched F1, F2, F3, F4, and F8 states;
 - artifact payload compatibility, anti-bypass behavior, and final phase closing.
 
@@ -73,6 +74,7 @@ These suites fix:
 - new-session versus resume Pi prompts;
 - refusal to resume finalized, archived, foreign, unavailable, or read-only sessions;
 - Pi RPC to client event mapping, SSE replay/reset behavior, and runtime replacement ordering;
+- reserved Pi phase notifications mapped to sanitized `phase_started` client events;
 - failure persistence and sanitization before a client-visible response.
 
 ### Frontend client
@@ -92,6 +94,7 @@ These suites fix:
 
 - widget registry and gate response payloads;
 - `ui_request`, `text_delta`, activity, usage, and lifecycle event reduction;
+- phase progress and the active workflow dot advancing on `phase_started` without a `ui_request`;
 - stream replacement, cursor reset, reconnection, and pending-text flush behavior;
 - session document projections shown to the reviewer.
 
diff --git a/frontend/src/api/types.ts b/frontend/src/api/types.ts
index 61d1b4f1..15f1c53d 100644
--- a/frontend/src/api/types.ts
+++ b/frontend/src/api/types.ts
@@ -98,7 +98,7 @@ export type StreamEvent =
     }
   | { type: "usage"; usage: TokenUsage }
   | { type: "info"; level?: "info" | "warning" | "error"; text: string }
-  | { type: "system_event"; event: string };
+  | { type: "system_event"; event: string; phase?: string };
 
 export interface SessionSummary {
   id: string;
diff --git a/frontend/src/shell/WorkflowBar.test.tsx b/frontend/src/shell/WorkflowBar.test.tsx
index 59090edb..86b6b5b4 100644
--- a/frontend/src/shell/WorkflowBar.test.tsx
+++ b/frontend/src/shell/WorkflowBar.test.tsx
@@ -29,6 +29,18 @@ test("dots carry done / running / pending states around the active phase", () =>
   expect(screen.getByTestId("phase-F5")).toHaveAttribute("data-state", "pending");
 });
 
+test("phase_started colors a phase even when no human gate was rendered", () => {
+  const store = useSessionStore.getState();
+  store.setPhase("F1");
+  store.applyEvent({ type: "system_event", event: "phase_started", phase: "F2" });
+
+  render(<WorkflowBar />);
+
+  expect(screen.getByTestId("phase-F1")).toHaveAttribute("data-state", "done");
+  expect(screen.getByTestId("phase-F2")).toHaveAttribute("data-state", "running");
+  expect(screen.getByTestId("phase-F3")).toHaveAttribute("data-state", "pending");
+});
+
 test("the active dot turns to the error state when phaseError flags it", () => {
   const st = useSessionStore.getState();
   st.applyEvent({ type: "ui_request", ui_request: { id: "u", widget: "select", phase: "F3_x" } });
diff --git a/frontend/src/store/sessionStore.test.ts b/frontend/src/store/sessionStore.test.ts
index 4cf65eae..e073ea4b 100644
--- a/frontend/src/store/sessionStore.test.ts
+++ b/frontend/src/store/sessionStore.test.ts
@@ -184,6 +184,19 @@ test("ui_request without a phase keeps the existing currentPhase", () => {
   expect(useSessionStore.getState().currentPhase).toBe("F2");
 });
 
+test("phase_started advances progress even when the phase has no human gate", () => {
+  const store = useSessionStore.getState();
+  store.setPhase("F1");
+
+  store.applyEvent({
+    type: "system_event",
+    event: "phase_started",
+    phase: "F2_memory",
+  });
+
+  expect(useSessionStore.getState().currentPhase).toBe("F2");
+});
+
 test("agentActive lifecycle: off by default, on with activity, off on agent_end", () => {
   const st = useSessionStore.getState();
   expect(useSessionStore.getState().agentActive).toBe(false);
diff --git a/frontend/src/store/sessionStore.ts b/frontend/src/store/sessionStore.ts
index 926bff99..8222dbcf 100644
--- a/frontend/src/store/sessionStore.ts
+++ b/frontend/src/store/sessionStore.ts
@@ -176,14 +176,26 @@ export const useSessionStore = create<SessionState>((set) => ({
           : { stepMessages, activityLog };
       }
       if (e.type === "system_event") {
+        const currentPhase = e.event === "phase_started"
+          ? phaseOf(e.phase, st.currentPhase)
+          : st.currentPhase;
         const activityLog = [
           ...st.activityLog,
           {
             kind: "lifecycle" as const,
-            phase: st.currentPhase,
+            phase: currentPhase,
             text: lifecycleText(e.event),
           },
         ];
+        if (e.event === "phase_started") {
+          return {
+            lastSystemEvent: e,
+            activityLog,
+            currentPhase,
+            phaseError: null,
+            agentActive: true,
+          };
+        }
         return e.event === "agent_end"
           ? { lastSystemEvent: e, activityLog, agentActive: false }
           : { lastSystemEvent: e, activityLog };
diff --git a/harness/.pi/extensions/gate/__tests__/gate_phase_observability.test.js b/harness/.pi/extensions/gate/__tests__/gate_phase_observability.test.js
new file mode 100644
index 00000000..82bd7afd
--- /dev/null
+++ b/harness/.pi/extensions/gate/__tests__/gate_phase_observability.test.js
@@ -0,0 +1,59 @@
+const test = require("node:test");
+const assert = require("node:assert");
+const cp = require("node:child_process");
+const path = require("node:path");
+const { createRequire } = require("node:module");
+const { createFakePi } = require("./fake_pi_runtime.js");
+
+const GATE = path.join(__dirname, "..", "..", "tht-gate.js");
+globalThis.require = createRequire(GATE);
+
+let phase = 2;
+cp.execFileSync = (_file, args) => {
+  if (args.join(" ") === "phase meta --json") {
+    return JSON.stringify({
+      max_phase: 8,
+      phases: Array.from({ length: 8 }, (_, index) => ({
+        num: index + 1,
+        id: `F${index + 1}`,
+        name: `phase-${index + 1}`,
+        emits: [],
+      })),
+    });
+  }
+  if (args.slice(0, 4).join(" ") === "phase show --session session-1") {
+    return `Fase corrente: ${phase}\n`;
+  }
+  return "";
+};
+
+const installGate = require(GATE).default ?? require(GATE);
+
+test("tool completion announces each newly active phase even without a reviewer gate", async () => {
+  const { pi, ctx } = createFakePi();
+  ctx.mode = "rpc";
+  installGate(pi);
+  await pi.emit("session_start", {});
+
+  await pi.emit("tool_result", {
+    toolName: "reviewer_select",
+    input: { session: "session-1" },
+    isError: false,
+  });
+  phase = 3;
+  await pi.emit("tool_result", {
+    toolName: "reviewer_decide",
+    input: { session: "session-1" },
+    isError: false,
+  });
+  await pi.emit("tool_result", {
+    toolName: "reviewer_decide",
+    input: { session: "session-1" },
+    isError: false,
+  });
+
+  assert.deepEqual(ctx.notifications, [
+    { message: "__tht_phase_started__:F2", level: "info" },
+    { message: "__tht_phase_started__:F3", level: "info" },
+  ]);
+});
diff --git a/harness/.pi/extensions/tht-gate.js b/harness/.pi/extensions/tht-gate.js
index 6cf8179d..32a71b39 100644
--- a/harness/.pi/extensions/tht-gate.js
+++ b/harness/.pi/extensions/tht-gate.js
@@ -52,6 +52,11 @@ import {
 } from "./gate/disambiguation/index.js";
 import { isReserved } from "./gate/core/reserved-labels.mjs";
 
+// Machine-readable RPC notification consumed by SessionBridge. Pi's extension API
+// exposes notify/input but no custom client-event emitter, so this reserved prefix is
+// the narrow transport contract for phase progress that does not require a human gate.
+export const PHASE_STARTED_NOTIFICATION_PREFIX = "__tht_phase_started__:";
+
 // Load the workflow contract once when Pi loads the extension. Asking the model to
 // discover/read the skill as its first action proved unreliable with remote models:
 // they can spend the whole RPC turn exploring the repository before opening the exact
@@ -596,6 +601,18 @@ export default function (pi) {
 	let lastSteered = false;
 	let pendingKickoff = null;
 	let activeSessionId = null;
+	const announcedPhases = new Map();
+	const announceCurrentPhase = async (ctx, session) => {
+		if (ctx.mode !== "rpc" || typeof session !== "string" || !session.trim()) return;
+		try {
+			const phase = phaseId(ctx, currentPhase(ctx, session));
+			if (!/^F[1-8]$/.test(phase) || announcedPhases.get(session) === phase) return;
+			await ctx.ui.notify(`${PHASE_STARTED_NOTIFICATION_PREFIX}${phase}`, "info");
+			announcedPhases.set(session, phase);
+		} catch {
+			// Progress reporting is observational: it must never block the workflow.
+		}
+	};
 	const memoryGate = createMemoryGate({
 		workflow: {
 			activate: () => {
@@ -748,7 +765,8 @@ export default function (pi) {
 
 	// 3) BEFORE_AGENT_START: one-shot kickoff injection (appends the operational
 	//    instructions to the system prompt on the turn that starts/resumes a session).
-	pi.on("before_agent_start", (event, ctx) => {
+	pi.on("before_agent_start", async (event, ctx) => {
+		await announceCurrentPhase(ctx, process.env.THT_SESSION);
 		if (!pendingKickoff) return undefined;
 		const sessionId = process.env.THT_SESSION;
 		const isProvidedNewSession =
@@ -789,9 +807,18 @@ export default function (pi) {
 			lastSteered = false;
 		}
 		activeSessionId = null;
+		announcedPhases.clear();
 		_phaseMetaCache = null;
 	});
 
+	// A reviewer tool is the ownership boundary that persists a decision and may
+	// advance the folded workflow phase. Observe the persisted phase after the tool
+	// completes, including auto-approved phases that never open a human widget.
+	pi.on("tool_result", async (event, ctx) => {
+		const session = typeof event.input?.session === "string" ? event.input.session : null;
+		if (session) await announceCurrentPhase(ctx, session);
+	});
+
 	// 5) AGENT_END prose safety net: if the model emits prose instead of a reviewer_*
 	//    tool call (and the lock is active), nudge it back to the gate tools.
 	pi.on("agent_end", async (event) => {