feat: the plan verdict gate — acceptance is the plan→teach seam

The accept-plan UI lands (docs/probe-teach-split.md §4, formerly the
interim rule): presenting the plan no longer moves the phase — the
learner's ACCEPT does. While the presented plan awaits its verdict, the
composer's send square becomes two stacked buttons (green Accept plan /
red Decline); typed text rides the verdict as his note, Enter keeps
sending plain side questions (phase unmoved), decline asks for a
revision and the buttons stay.

The seam: accept sends a user message carrying a data-plan-accepted
part (PlanAcceptedData in contracts/chat.ts, TeacherUIDataParts
'plan-accepted'); phaseAt3 reads it as the plan→teach event (plan_init
demoted to presentation-only); convertToModelMessages drops data parts,
so the teacher sees only the text. Mid-lesson rewrites need no fresh
verdict — acceptance happens once, at the first presentation.

The teacher's planning prompt now ends the turn at presentation and
waits for the verdict (never teaches into an unaccepted plan).

Gates: tsc clean, 304/304 (phases tests rewritten to the acceptance
seam incl. decline/side-question/failed-init cases; composer verdict
render tests), lint, build. Live GLM smoke ALL PASS: phase pinned at
'plan' after plan_init, presentation turn carried NO check, accept
click flipped the summary to 'teach', then tagged checks moved the map
(current=rates, visited=composite); zero console errors.

components/chat.tsx

@@ -21,7 +21,7 @@ import { SubagentSteerCard } from "@/components/artifacts/steer-card";
 import { Composer } from "@/components/composer";
 import { JobsContext } from "@/components/jobs-context";
 import { StatsBar } from "@/components/stats-bar";
-import { PlanBlock, PlanPopup } from "@/components/plan-block";
+import { PlanBlock, PlanPopup, latestTree } from "@/components/plan-block";
 import { PlanWindow } from "@/components/plan-window";
 import type { PlanBlockData } from "@/src/core";
 import { QuestionDock } from "@/components/question-dock";
@@ -181,6 +181,37 @@ export function Chat({
 	// The live plan popup (wave 4): opened by any transcript plan block.
 	const [planOpen, setPlanOpen] = useState(false);
 
+	// ── The plan verdict gate (docs/probe-teach-split.md §4) ──
+	// The plan has been presented (a tree exists) and the session still sits in
+	// the planning phase → the composer's send square becomes the stacked
+	// Accept / Decline buttons. Acceptance is the explicit plan→teach seam
+	// (a data-plan-accepted part on the message); decline asks for revision.
+	const planVerdict = useMemo(
+		() => phaseAt3(messages) === "plan" && latestTree(messages) !== null,
+		[messages],
+	);
+	const sendVerdict = useCallback(
+		(accepted: boolean) => {
+			const note = text.trim();
+			setText("");
+			if (accepted) {
+				void sendMessage({
+					parts: [
+						{ type: "text", text: note || "The plan is accepted — begin teaching." },
+						{
+							type: "data-plan-accepted",
+							id: `pa_${Date.now().toString(36)}_${crypto.randomUUID().slice(0, 8)}`,
+							data: { at: new Date().toISOString() },
+						},
+					],
+				});
+			} else {
+				void sendMessage({ text: note || "I'd like the plan revised before we begin." });
+			}
+		},
+		[text, sendMessage],
+	);
+
 	// ── Session usage (wave-4 stats bar) ──
 	// The money channel: the record's turns log, folded client-side by
 	// core/prices.ts. Seeded once on mount (the page doesn't carry turns),
@@ -489,6 +520,14 @@ export function Chat({
 									onSend={onSend}
 									onStop={() => stop()}
 									canSend={canSend}
+									verdict={
+										planVerdict
+											? {
+													onAccept: () => sendVerdict(true),
+													onDecline: () => sendVerdict(false),
+												}
+											: undefined
+									}
 								/>
 							}
 							onSubmitAnswer={(output) => {

components/composer.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { CornerDownLeftIcon, SquareIcon } from "lucide-react";
+import { CheckIcon, CornerDownLeftIcon, SquareIcon, XIcon } from "lucide-react";
 import { cn } from "@/lib/utils";
 
 /**
@@ -19,6 +19,7 @@ export function Composer({
 	onStop,
 	canSend,
 	autoFocus,
+	verdict,
 }: {
 	busy: boolean;
 	value: string;
@@ -27,6 +28,10 @@ export function Composer({
 	onStop: () => void;
 	canSend: boolean;
 	autoFocus?: boolean;
+	/** The plan verdict gate: while the presented plan awaits the learner's
+	 *  word, the send square becomes two stacked buttons — green accept,
+	 *  red decline. Typed text rides the verdict as his note. */
+	verdict?: { onAccept: () => void; onDecline: () => void };
 }) {
 	return (
 		<form
@@ -56,19 +61,42 @@ export function Composer({
 				rows={1}
 				className="field-sizing-content max-h-48 min-h-10 flex-1 resize-none bg-transparent px-2.5 py-2 text-sm outline-none placeholder:text-muted-foreground"
 			/>
-			<button
+			{verdict && !busy ? (
-				type="submit"
+				// The plan verdict (docs/probe-teach-split.md §4): accept
-				aria-label={busy ? "Stop" : "Send"}
+				// sanctions teaching (phase plan→teach); decline sends the
-				disabled={!busy && !canSend}
+				// revision request. Enter keeps sending a plain message —
-				className={cn(
+				// side questions stay possible while the verdict pends.
-					"flex size-10 shrink-0 items-center justify-center rounded-[10px] transition-colors",
+				<div className="flex shrink-0 flex-col justify-end gap-1" data-testid="plan-verdict-buttons">
-					busy
+					<button
-						? "bg-secondary text-foreground hover:bg-accent"
+						type="button"
-						: "bg-primary text-primary-foreground hover:opacity-90 disabled:opacity-40",
+						onClick={verdict.onAccept}
-				)}
+						className="flex h-[19px] items-center justify-center gap-1 rounded-md bg-emerald-600 px-3 text-[11px] font-medium text-white transition-colors hover:bg-emerald-500"
-			>
+					>
-				{busy ? <SquareIcon className="size-4" /> : <CornerDownLeftIcon className="size-5" />}
+						<CheckIcon className="size-3" /> Accept plan
-			</button>
+					</button>
+					<button
+						type="button"
+						onClick={verdict.onDecline}
+						className="flex h-[19px] items-center justify-center gap-1 rounded-md bg-destructive px-3 text-[11px] font-medium text-destructive-foreground transition-colors hover:opacity-90"
+					>
+						<XIcon className="size-3" /> Decline
+					</button>
+				</div>
+			) : (
+				<button
+					type="submit"
+					aria-label={busy ? "Stop" : "Send"}
+					disabled={!busy && !canSend}
+					className={cn(
+						"flex size-10 shrink-0 items-center justify-center rounded-[10px] transition-colors",
+						busy
+							? "bg-secondary text-foreground hover:bg-accent"
+							: "bg-primary text-primary-foreground hover:opacity-90 disabled:opacity-40",
+					)}
+				>
+					{busy ? <SquareIcon className="size-4" /> : <CornerDownLeftIcon className="size-5" />}
+				</button>
+			)}
 		</form>
 	);
 }

docs/probe-teach-split.md

@@ -100,8 +100,15 @@ presents the plan → **accept** → **teach (teacher)**
 
 - The broken derived-occupancy seam (phase-of-tree via `currentNodeId`
   nothing ever sets — the stuck-on-plan bug) is **replaced, not patched**.
-- Interim rule until the accept-plan UI lands: a successful `plan_init`
+- The verdict gate is LIVE (landed 2026-09-11, same day): presenting the
-  marks plan→teach. (The accept gate is designed but deferred — §7.)
+  plan (`plan_init`) does NOT move the phase — the learner's **accept**
+  does. The composer's send square becomes two stacked buttons (green
+  Accept plan / red Decline) while the verdict pends; accept sends a user
+  message carrying a `data-plan-accepted` data part — THE plan→teach seam
+  (`phaseAt3` reads it; `convertToModelMessages` drops data parts, so the
+  teacher sees only the text). Decline asks for a revision; side questions
+  stay possible (Enter sends a plain message, phase unmoved). Mid-lesson
+  rewrites need no fresh verdict: acceptance happens once.
 - The session picker phase derives from transcript markers the same way.
 
 ## 5. No global-graph context in sessions (for now)
@@ -120,21 +127,21 @@ processes dock): always present, zoomed on the current node, auto-moving
 as the lesson advances; click → full plan (the existing popup survives as
 the expanded view). Exact layout/design is refined in the UI session.
 
-Interim until that wave: the full plan block still renders in the flow at
+The window is LIVE (landed 2026-09-11, one day after the design): bottom-left,
-plan authoring (plan presentation moment; statuses are accurate at that
+2:1 zoomed viewBox centered on the current node, clamped to the layout, click
-instant) and remains the popup's entry point. The neighborhood-block
+opens the popup. The full plan block also still renders in the flow at plan
+authoring (the presentation moment; the block sits immediately after the
+`plan_init` call) as a second popup entry point. The neighborhood-block
 machinery (frozen fragments) is retired — snapshots can't represent
 live-derived movement.
 
 ## 7. Deferred / later waves (designed, not now)
 
-- **Accept-plan UI** — when the teacher presents the plan, the composer
+- ~~**Accept-plan UI**~~ — **landed 2026-09-11** (see §4): stacked
-  changes to a formal accept control (two send buttons: green accept-plan /
+  Accept/Decline buttons; the `data-plan-accepted` part is the seam.
-  continue; red decline) — first `plan_init` only, never re-authorings.
-  That acceptance is the explicit planning→teach signal. Ideated in the UI
-  session.
 - **Assessment viewer** — the strand assessments displayed to the learner
-  as a proper card (data already durable in the transcript).
+  as a proper card (data already durable in the transcript; the plain v1
+  probe-done card renders the assessment meanwhile).
 - **Model / thinking control** — currently hardcoded per role in
   `config.ts` MODELS. The split gives natural `MODELS.prober` /
   `MODELS.teacher` entries; runtime control comes after.

next-env.d.ts

@@ -1,7 +1,7 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/types/routes.d.ts";
+import "./.next/dev/types/routes.d.ts";
-import "./.next/types/root-params.d.ts";
+import "./.next/dev/types/root-params.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

src/agent/prompts/teacher/10-planning.md

@@ -51,4 +51,9 @@ Two parts:
 
 **Stress-test the roots before presenting.** For every node you're treating as foundational, ask: is this genuinely an unconditional truth *for him*, or a disguised theorem that itself derives from something simpler he'd accept at face value? If it derives, push it down and extend the map — never found the lesson on a mid-level fact. A wrong root corrupts everything hung off it, and roots are far easier to audit in a drawn map than mid-flow.
 
-After presenting, invite his read on the plan and begin teaching — a formal accept/decline gate is coming to the UI later; for now his first response is your checkpoint: if he objects to a root or the scope, fix the map (`plan_init` again) before teaching.
+**Presenting ENDS your turn.** The moment the plan is presented, his interface shows two verdict buttons — Accept plan / Decline — and the session waits for his word before any teaching is sanctioned. Do not ask a check or teach before it arrives.
+
+- **Acceptance** arrives as a message like "[Plan accepted] — begin teaching." Begin the first node.
+- **Decline** arrives as a revision request. Ask what he'd like changed if it isn't clear, fix the map (`plan_init` again — a wholesale rewrite), present again, and wait once more.
+
+The verdict is his alone to give — never ask a question whose answer would assume it, and never start teaching into an unaccepted plan. A plan he interacts with mid-lesson (a `plan_init` rewrite during teaching) needs no fresh verdict: acceptance happens once, at the first presentation.

src/core/contracts/chat.ts

@@ -123,6 +123,16 @@ export interface TurnUsage {
  * block renders current node + direct parents + direct children in its own
  * small container, the current node glowing — clearly a fragment, not the
  * whole plan. Clicking either opens the full plan in a popup. */
+/** The learner's plan-acceptance marker (docs/probe-teach-split.md §4): a
+ *  data part riding the accept-click user message. It is THE plan→teach
+ *  phase seam — phaseAt3 reads it from the transcript;
+ *  convertToModelMessages drops data parts, so the teacher only sees the
+ *  message's text; the marker is for derivation and the UI. */
+export interface PlanAcceptedData {
+	/** ISO timestamp of the accept click. */
+	at: string;
+}
+
 export interface PlanBlockData {
 	/** Only "full" survives (the 2026-09-11 pivot): the plan renders IN
 	 *  FLOW once, at authoring. The neighborhood fragments are retired —

src/core/phases.ts

@@ -5,10 +5,11 @@
  *
  *   probe  — until the first message containing a `tool-probe_done` part
  *            (the prober concludes; the assessment rides the tool part)
- *   plan   — probe concluded, until the first successful `plan_init`
+ *   plan   — probe concluded, until the learner ACCEPTS the presented
- *            (the teacher presents the map; interim rule until the
+ *            plan (a `data-plan-accepted` part on the accept button's
- *            accept-plan UI lands — then acceptance becomes the seam)
+ *            user message — the explicit verdict gate; plan_init itself
- *   teach  — a plan exists
+ *            is only the PRESENTATION and moves no phase)
+ *   teach  — teaching is sanctioned
  *
  * The former derived-occupancy seam (phase-of-tree via `currentNodeId`)
  * is GONE: nothing ever writes currentNodeId (the stuck-on-plan bug — a
@@ -22,9 +23,6 @@
 /** The three phases of a session, as the picker / header / dividers see them. */
 export type Phase3 = "probe" | "plan" | "teach";
 
-/** The advance-only order of phases: a session never visibly regresses. */
-const PHASE3_RANK: Record<Phase3, number> = { probe: 0, plan: 1, teach: 2 };
-
 /**
  * Minimal structural slice of a UI message for the phase scan: parts with
  * a state and (for concluded calls) an output.
@@ -33,10 +31,6 @@ export interface PhaseMessage {
 	parts: ReadonlyArray<{ type: string; state?: string; output?: unknown }>;
 }
 
-interface PlanOutput {
-	tree?: { nodes?: unknown };
-}
-
 /** The phase at `upToIndex` (inclusive; default: the last message). */
 export function phaseAt3(messages: readonly PhaseMessage[], upToIndex?: number): Phase3 {
 	let phase: Phase3 = "probe";
@@ -55,15 +49,15 @@ function advance(
 	if (!parts) return phase;
 	for (const part of parts) {
 		// STRICTLY SEQUENTIAL: probe → plan only via a concluded probe_done,
-		// plan → teach only via a successful plan_init. A marker out of order
+		// plan → teach only via the learner's plan acceptance
-		// (e.g. a legacy plan_init with no probe) advances nothing — the chain
+		// (data-plan-accepted). A marker out of order advances nothing — the
-		// never skips, and the rank table below only guards regressions.
+		// chain never skips. plan_init PRESENTS the map; only the verdict
+		// (the accept button's marker part) sanctions teaching.
 		if (phase === "probe" && part.type === "tool-probe_done" && part.state === "output-available") {
 			phase = "plan";
 		}
-		if (phase === "plan" && part.type === "tool-plan_init" && part.state === "output-available") {
+		if (phase === "plan" && part.type === "data-plan-accepted") {
-			const tree = (part.output as PlanOutput | undefined)?.tree;
+			phase = "teach";
-			if (tree && Array.isArray(tree.nodes) && tree.nodes.length > 0) phase = "teach";
 		}
 	}
 	return phase;

src/core/ui-message.ts

@@ -1,6 +1,7 @@
 import type { UIMessage } from "ai";
 import type {
 	DemoToolInput,
+	PlanAcceptedData,
 	PlanBlockData,
 	ProbeDoneInput,
 	ProbeDoneResult,
@@ -37,6 +38,9 @@ export type TeacherUIDataParts = {
 	"subagent-artifact": SubagentArtifactData;
 	/** Plan blocks (wave 4): frozen plan snapshots rendered in the chat flow. */
 	"plan-block": PlanBlockData;
+	/** The plan-acceptance marker: the accept button's user message carries
+	 *  it — the plan→teach phase seam (docs/probe-teach-split.md §4). */
+	"plan-accepted": PlanAcceptedData;
 };
 
 export type TeacherUIMessage = UIMessage<unknown, TeacherUIDataParts, TeacherUITools>;

tests/composer-verdict.test.tsx

@@ -0,0 +1,54 @@
+import { renderToStaticMarkup } from "react-dom/server";
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+import { Composer } from "../components/composer.tsx";
+
+// The plan verdict gate (docs/probe-teach-split.md §4): while the presented
+// plan awaits the learner's word, the composer's send square becomes two
+// stacked buttons — green Accept plan, red Decline.
+
+describe("Composer verdict buttons", () => {
+	const noop = () => {};
+
+	it("no verdict: the normal send square renders", () => {
+		const html = renderToStaticMarkup(
+			<Composer busy={false} value="" onChange={noop} onSend={noop} onStop={noop} canSend />,
+		);
+		assert.ok(!html.includes("plan-verdict-buttons"));
+		assert.ok(html.includes('aria-label="Send"'));
+	});
+
+	it("verdict pending: two stacked buttons replace the send square; stop square gone", () => {
+		const html = renderToStaticMarkup(
+			<Composer
+				busy={false}
+				value=""
+				onChange={noop}
+				onSend={noop}
+				onStop={noop}
+				canSend
+				verdict={{ onAccept: noop, onDecline: noop }}
+			/>,
+		);
+		assert.ok(html.includes('data-testid="plan-verdict-buttons"'));
+		assert.ok(html.includes("Accept plan"));
+		assert.ok(html.includes("Decline"));
+		assert.ok(!html.includes('aria-label="Send"'), "no send square while the verdict pends");
+	});
+
+	it("busy: the stop square wins even while a verdict pends (no verdict mid-turn)", () => {
+		const html = renderToStaticMarkup(
+			<Composer
+				busy
+				value=""
+				onChange={noop}
+				onSend={noop}
+				onStop={noop}
+				canSend={false}
+				verdict={{ onAccept: noop, onDecline: noop }}
+			/>,
+		);
+		assert.ok(html.includes('aria-label="Stop"'));
+		assert.ok(!html.includes("plan-verdict-buttons"));
+	});
+});

tests/phases.test.ts

@@ -2,9 +2,11 @@
  * phases — the event-driven phase chain (docs/probe-teach-split.md §4).
  *
  * probe ends at the first CONCLUDED probe_done (output-available); planning
- * ends at the first successful plan_init (a tree with nodes). No stored-tree
+ * ends at the LEARNER'S plan acceptance (a data-plan-accepted part on the
- * seam: the phase is a pure fold over the transcript, so it can never stick
+ * accept button's user message — plan_init only PRESENTS the map). No
- * (the old currentNodeId-based phaseOfTree read a field nothing ever set).
+ * stored-tree seam: the phase is a pure fold over the transcript, so it can
+ * never stick (the old currentNodeId-based phaseOfTree read a field nothing
+ * ever set).
  */
 import assert from "node:assert";
 import test from "node:test";
@@ -32,7 +34,19 @@ function assistantTool(
 const DONE_ASSESSMENT = { assessment: { strands: [{ strand: "s", assessment: "a" }] } };
 const PLAN_OK = { ok: true, tree: { nodes: [{ id: "n1", title: "N" }], edges: [] } };
 
-test("phaseAt3: probe until a concluded probe_done; plan until a successful plan_init; teach after", () => {
+/** The accept button's user message (text + marker data part). */
+function planAccepted(): UIMessage {
+	return {
+		id: `u_accept_${Math.random().toString(36).slice(2, 6)}`,
+		role: "user",
+		parts: [
+			{ type: "text", text: "The plan is accepted — begin teaching." },
+			{ type: "data-plan-accepted", id: "pa_1", data: { at: "2026-09-11T00:00:00Z" } } as never,
+		],
+	};
+}
+
+test("phaseAt3: probe until a concluded probe_done; plan until the learner ACCEPTS; teach after", () => {
 	const probe = phaseAt3([user("teach me calculus"), assistantTool("quiz", "output-available")]);
 	assert.equal(probe, "probe", "quiz answers alone never end the probe");
 
@@ -42,19 +56,37 @@ test("phaseAt3: probe until a concluded probe_done; plan until a successful plan
 	]);
 	assert.equal(concluded, "plan", "a concluded probe_done ends the probe (planning begins)");
 
-	const plan = phaseAt3([
+	const presented = phaseAt3([
 		user("teach me"),
 		assistantTool("probe_done", "output-available", DONE_ASSESSMENT),
 		assistantTool("plan_init", "output-available", PLAN_OK),
 	]);
-	assert.equal(plan, "teach", "a successful plan_init ends planning");
+	assert.equal(presented, "plan", "a successful plan_init PRESENTS the map — planning continues until the verdict");
+
+	const accepted = phaseAt3([
+		user("teach me"),
+		assistantTool("probe_done", "output-available", DONE_ASSESSMENT),
+		assistantTool("plan_init", "output-available", PLAN_OK),
+		planAccepted(),
+	]);
+	assert.equal(accepted, "teach", "the learner's acceptance ends planning");
+
+	const declined = phaseAt3([
+		user("teach me"),
+		assistantTool("probe_done", "output-available", DONE_ASSESSMENT),
+		assistantTool("plan_init", "output-available", PLAN_OK),
+		user("revise it"),
+		assistantTool("plan_init", "output-available", PLAN_OK),
+	]);
+	assert.equal(declined, "plan", "a declined plan stays in planning until a later acceptance");
 
 	const failedPlan = phaseAt3([
 		user("teach me"),
 		assistantTool("probe_done", "output-available", DONE_ASSESSMENT),
 		assistantTool("plan_init", "output-error", { ok: false, error: "bad mermaid" }),
+		planAccepted(),
 	]);
-	assert.equal(failedPlan, "plan", "a failed plan_init does not end planning");
+	assert.equal(failedPlan, "teach", "acceptance sanctions teaching even after a failed init attempt — the verdict is his");
 });
 
 test("phaseAt3: a mere probe_done CALL (input-available, not yet concluded) keeps the probe open", () => {
@@ -73,10 +105,12 @@ test("phaseTimeline: folds messages into phase spans for the dividers", () => {
 		assistantTool("quiz", "output-available"),
 		assistantTool("probe_done", "output-available", DONE_ASSESSMENT),
 		assistantTool("plan_init", "output-available", PLAN_OK),
+		user("what does node 1 mean?"), // side question — still planning
+		planAccepted(),
 		user("go on"),
 	]);
-	assert.deepEqual(timeline satisfies Phase3[], ["probe", "probe", "plan", "teach", "teach"]);
+	assert.deepEqual(timeline satisfies Phase3[], ["probe", "probe", "plan", "plan", "plan", "teach", "teach"]);
-	assert.equal(timeline.length, 5);
+	assert.equal(timeline.length, 7);
 });
 
 test("phaseAt3: empty transcript is probe", () => {