diff --git a/app/api/chats/[id]/settings/route.ts b/app/api/chats/[id]/settings/route.ts
index 2d8fc9f..869d078 100644
--- a/app/api/chats/[id]/settings/route.ts
+++ b/app/api/chats/[id]/settings/route.ts
@@ -1,6 +1,6 @@
 import { getChat, validateChatSettings, stores } from "@/src/server";
 import type { ThinkingLevel } from "@earendil-works/pi-agent-core";
-import type { ChatSettings } from "@/src/core";
+import { GRAPH_CONTEXT_TOKENS_MAX, type ChatSettings } from "@/src/core";
 
 /**
  * The per-chat model control (model-control wave): replace-whole settings —
@@ -16,7 +16,7 @@ export async function PUT(req: Request, { params }: { params: Promise<{ id: stri
 	if (!getChat(id)) return Response.json({ error: "Not found" }, { status: 404 });
 
 	const body = (await req.json().catch(() => null)) as
-		| { model?: { provider?: unknown; id?: unknown }; thinkingLevel?: unknown }
+		| { model?: { provider?: unknown; id?: unknown }; thinkingLevel?: unknown; graphContextTokens?: unknown }
 		| null;
 	if (!body || typeof body !== "object") {
 		return Response.json({ error: "Invalid JSON body" }, { status: 400 });
@@ -39,6 +39,23 @@ export async function PUT(req: Request, { params }: { params: Promise<{ id: stri
 		}
 		settings.thinkingLevel = body.thinkingLevel as ThinkingLevel;
 	}
+	// Graph context injection budget (vision-context-injection.md): integer
+	// tokens, 0 (off) to GRAPH_CONTEXT_TOKENS_MAX, no silent clamping — the
+	// slider is the only writer, and it only ever sends multiples of the step.
+	if (body.graphContextTokens !== undefined) {
+		if (
+			typeof body.graphContextTokens !== "number" ||
+			!Number.isInteger(body.graphContextTokens) ||
+			body.graphContextTokens < 0 ||
+			body.graphContextTokens > GRAPH_CONTEXT_TOKENS_MAX
+		) {
+			return Response.json(
+				{ error: `graphContextTokens must be an integer between 0 and ${GRAPH_CONTEXT_TOKENS_MAX}` },
+				{ status: 400 },
+			);
+		}
+		settings.graphContextTokens = body.graphContextTokens;
+	}
 
 	const verdict = validateChatSettings(settings);
 	if (!verdict.ok) {
diff --git a/components/activity-dock.tsx b/components/activity-dock.tsx
index f965409..cba0669 100644
--- a/components/activity-dock.tsx
+++ b/components/activity-dock.tsx
@@ -1,7 +1,7 @@
 "use client";
 
 import { createContext, useCallback, useContext, useEffect, useMemo, useRef, useState } from "react";
-import { ActivityIcon, BotIcon, PenToolIcon, PlayIcon, SearchIcon, SquareIcon, WaypointsIcon } from "lucide-react";
+import { ActivityIcon, BookOpenIcon, BotIcon, PenToolIcon, PlayIcon, SearchIcon, SquareIcon, WaypointsIcon } from "lucide-react";
 import { cn } from "@/lib/utils";
 import type { CallUsage, JobKind, JobRecord } from "@/src/core";
 import { CONTEXT_LIMITS, jobCost } from "@/src/core";
@@ -204,6 +204,7 @@ const KIND_ICON: Record<JobKind, typeof SearchIcon> = {
 	research: SearchIcon,
 	demo: PlayIcon,
 	visual: PenToolIcon,
+	"graph-context": BookOpenIcon,
 };
 
 /** Abort states per blob id: pending (fired) / failed (backend absent). */
@@ -318,7 +319,9 @@ function ActivityBlobRow({
 					? "Demo builder"
 					: blob.jobKind === "visual"
 						? "Figure maker"
-						: "Sub-agent";
+						: blob.jobKind === "graph-context"
+							? "Knowledge context"
+							: "Sub-agent";
 	return (
 		<div
 			data-testid={`activity-blob-${blob.process}`}
diff --git a/components/artifacts/dispatch-card.tsx b/components/artifacts/dispatch-card.tsx
index d5dbf68..29f8a8e 100644
--- a/components/artifacts/dispatch-card.tsx
+++ b/components/artifacts/dispatch-card.tsx
@@ -21,6 +21,9 @@ const KIND_LABEL: Record<JobKind, string> = {
 	research: "Research agent",
 	demo: "Demo agent",
 	visual: "Figure agent",
+	// The injection is server-initiated — it has no tool part, so never a
+	// dispatch card. The entry exists only for the exhaustive record.
+	"graph-context": "Knowledge context",
 };
 
 export function DispatchCard({ toolCallId, kind }: { toolCallId: string; kind: JobKind }) {
diff --git a/components/chat.tsx b/components/chat.tsx
index 8606b35..ec52e83 100644
--- a/components/chat.tsx
+++ b/components/chat.tsx
@@ -21,7 +21,8 @@ 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 type { ChatSettings } from "@/src/core";
+import { graphContextOfMessage, type ChatSettings } from "@/src/core";
+import { formatTokens } from "@/components/usage-format";
 import { PlanBlock, PlanPopup, latestTree } from "@/components/plan-block";
 import { PlanMarginalia } from "@/components/plan-window";
 import { WaypointsIcon } from "lucide-react";
@@ -81,6 +82,16 @@ const useIsoLayoutEffect = typeof window === "undefined" ? useEffect : useLayout
 
 /** A wake-pipeline steer message: user-role delivery whose metadata marks it
  * as a sub-agent result — rendered as an artifact card, never a bubble. */
+/** The knowledge-context card's one-liner: the numbers the observability
+ *  doctrine wants visible at the seam — tokens and proposition count
+ *  (parse-don't-cast; a malformed part still renders a quiet generic line). */
+function graphContextLine(message: { parts: ReadonlyArray<{ type: string; data?: unknown }> }): string {
+	const data = graphContextOfMessage(message);
+	return data
+		? `Knowledge context — ~${formatTokens(data.tokens)} · ${data.propositions.length} propositions`
+		: "Knowledge context";
+}
+
 /** The quiet system line (custom-message scheme rendering): centered, muted,
  *  small — the transcript's voice for events that are not speech (wake
  *  scaffolding, the learner's plan verdict). */
@@ -540,7 +551,14 @@ export function Chat({
 									// PROTOCOL" §4). Key fallback: legacy transcripts (pre id-hygiene)
 									// can still hold empty ids — the index keeps keys unique for them.
 									<SubagentSteerCard key={m.id || `m-${mi}`} message={m} />
-								) : m.role === "user" && m.parts.some((p) => p.type === "data-probe-handoff") ? (
+								) : m.role === "user" && m.parts.some((p) => p.type === "data-graph-context") ? (
+								// The prior-knowledge injection's delivery (vision-context-injection.md):
+								// quiet system line, the numbers only — the block itself was for the
+								// model (adapter flattening); the part data stays the audit trail.
+								<SystemLine key={m.id || `m-${mi}`} testId="graph-context">
+									{graphContextLine(m)}
+								</SystemLine>
+							) : m.role === "user" && m.parts.some((p) => p.type === "data-probe-handoff") ? (
 								// The probe→teach handoff wake (custom-message scheme): quiet
 								// system line, never a user bubble — the wake is scaffolding,
 								// the "Planning" divider marks the seam, and the model-facing
diff --git a/components/graph-context-control.tsx b/components/graph-context-control.tsx
new file mode 100644
index 0000000..2f24a39
--- /dev/null
+++ b/components/graph-context-control.tsx
@@ -0,0 +1,67 @@
+"use client";
+
+import { BookOpenIcon } from "lucide-react";
+import {
+	GRAPH_CONTEXT_TOKENS_DEFAULT,
+	GRAPH_CONTEXT_TOKENS_MAX,
+	GRAPH_CONTEXT_TOKENS_STEP,
+} from "@/src/core";
+import { formatTokens } from "@/components/usage-format";
+
+/**
+ * The knowledge-context budget control (vision-context-injection.md) — the
+ * "session data" section's one input, shown where sessions START: the home
+ * (graph) view's new-session dock and the /chat/new draft. Input before
+ * output: the panel that will later show what the session contributed to
+ * the graph asks first what the graph will contribute to the session.
+ *
+ * One quiet slider row: the token budget for the prior-knowledge block the
+ * injection steers in at session start. 0 = off; absent settings show the
+ * DEFAULT (1024 — on). The value rides ChatSettings (the same lifted
+ * settings the model picker uses), so it persists pre-chat via the same
+ * deferred PUT. Sessions never show this control — the injection is
+ * one-shot at session start, so mid-session there is nothing to decide.
+ */
+export function GraphContextControl({
+	value,
+	onChange,
+	testId = "graph-context-control",
+}: {
+	value: number;
+	onChange: (tokens: number) => void;
+	testId?: string;
+}) {
+	return (
+		<div
+			data-testid={testId}
+			className="flex items-center gap-2 px-1 text-xxs text-muted-foreground"
+		>
+			<BookOpenIcon className="size-3 shrink-0" />
+			<span className="shrink-0 uppercase tracking-widest">Knowledge context</span>
+			<input
+				type="range"
+				min={0}
+				max={GRAPH_CONTEXT_TOKENS_MAX}
+				step={GRAPH_CONTEXT_TOKENS_STEP}
+				value={value}
+				onChange={(e) => onChange(Number(e.target.value))}
+				aria-label="Prior-knowledge token budget"
+				className="h-1 flex-1 accent-primary"
+				data-testid="graph-context-slider"
+			/>
+			<span
+				className="w-16 shrink-0 text-right tabular-nums"
+				data-testid="graph-context-value"
+			>
+				{value === 0 ? "off" : `${formatTokens(value)} tokens`}
+			</span>
+		</div>
+	);
+}
+
+/** The control's effective value for a chat's settings — absent = the
+ *  default (on), never 0: the decided default is a modest slice of prior
+ *  knowledge for every fresh session. */
+export function effectiveContextTokens(settings: { graphContextTokens?: number } | undefined): number {
+	return settings?.graphContextTokens ?? GRAPH_CONTEXT_TOKENS_DEFAULT;
+}
\ No newline at end of file
diff --git a/components/home.tsx b/components/home.tsx
index a86300e..082dac5 100644
--- a/components/home.tsx
+++ b/components/home.tsx
@@ -4,6 +4,7 @@ import { useState } from "react";
 import { useRouter } from "next/navigation";
 import { CornerDownLeftIcon } from "lucide-react";
 import { GraphView } from "@/components/graph-view";
+import { GraphContextControl, effectiveContextTokens } from "@/components/graph-context-control";
 import { SidebarToggle } from "@/components/sidebar";
 import { StatsBar } from "@/components/stats-bar";
 import type { ChatSettings, TurnUsage } from "@/src/core";
@@ -71,6 +72,17 @@ export function Home() {
 			    px-4) so nothing shifts when a session starts (owner). */}
 			<div className="pointer-events-none absolute inset-x-0 bottom-0 pb-5">
 				<div className="pointer-events-auto mx-auto w-full max-w-[46rem] px-4">
+					{/* The session-data strip (vision-context-injection.md): what the
+					    graph will contribute to the session, decided before the session
+					    starts. Rides the same lifted settings as the model picker. */}
+					<div className="mb-1.5">
+						<GraphContextControl
+							value={effectiveContextTokens(settings)}
+							onChange={(tokens) =>
+								setSettings((s) => ({ ...s, graphContextTokens: tokens }))
+						}
+						/>
+					</div>
 					<form
 						className="flex items-end gap-1.5 rounded-2xl border bg-card p-1.5 shadow-lg"
 					onSubmit={(e) => {
diff --git a/components/model-picker.tsx b/components/model-picker.tsx
index 9dbba2c..3665b00 100644
--- a/components/model-picker.tsx
+++ b/components/model-picker.tsx
@@ -245,7 +245,9 @@ export function ModelControl({
 											effectiveLevel !== undefined && m.supportedLevels.includes(effectiveLevel)
 												? effectiveLevel
 												: undefined;
-										void save({ model: { provider: m.provider, id: m.id }, thinkingLevel: nextLevel });
+										// Replace-whole discipline: spread the current settings — a model pick
+									// must not silently clear a sibling override (graphContextTokens).
+									void save({ ...(settings ?? {}), model: { provider: m.provider, id: m.id }, thinkingLevel: nextLevel });
 									}}
 									className={`flex w-full flex-col gap-0.5 rounded-lg px-2 py-1.5 text-left transition-colors hover:bg-muted ${
 										m.id === effectiveId ? "bg-muted/60" : ""
diff --git a/components/new-session.tsx b/components/new-session.tsx
index f5faf00..496b505 100644
--- a/components/new-session.tsx
+++ b/components/new-session.tsx
@@ -4,6 +4,7 @@ import { useCallback, useState } from "react";
 import { useRouter } from "next/navigation";
 import { Conversation, ConversationContent, ConversationEmptyState } from "@/components/ai-elements/conversation";
 import { Composer } from "@/components/composer";
+import { GraphContextControl, effectiveContextTokens } from "@/components/graph-context-control";
 import { PhaseChip } from "@/components/phase-divider";
 import { SidebarToggle } from "@/components/sidebar";
 import { StatsBar } from "@/components/stats-bar";
@@ -98,6 +99,16 @@ export function DraftShell({
 						<div className="h-24 bg-gradient-to-t from-background via-background/85 to-transparent" />
 						<div className="bg-background pb-4">
 							<div className={DOCK}>
+								{/* The session-data strip (vision-context-injection.md) — same
+							    control as the home view, riding the same lifted settings. */}
+								<div className="mb-1.5">
+									<GraphContextControl
+										value={effectiveContextTokens(settings)}
+										onChange={(tokens) =>
+											onSettingsSaved({ ...settings, graphContextTokens: tokens })
+										}
+									/>
+								</div>
 								<div className="pointer-events-auto overflow-hidden rounded-2xl border bg-card shadow-lg">
 									<Composer
 										busy={busy}
diff --git a/src/agent/subagents/graph-context.ts b/src/agent/subagents/graph-context.ts
new file mode 100644
index 0000000..034d41c
--- /dev/null
+++ b/src/agent/subagents/graph-context.ts
@@ -0,0 +1,186 @@
+/**
+ * Graph context injection — the background runner
+ * (docs/vision-context-injection.md, settled 2026-09-14).
+ *
+ * One shot per chat, at session start: the first learner message is the
+ * session's TOPIC; it is embedded as a retrieval QUERY (the embedder's
+ * model-card format), the semantically closest graph propositions are
+ * selected under the session's token budget (pure core: selectGraphContext),
+ * and delivered as a marker-only STEER through the wake pipeline — the same
+ * gates as sub-agent results: it queues behind a pending quiz and rides the
+ * turn after the learner's answer. The prober typically opens with a run of
+ * quiz/ask calls, so delivery lands mid-probing, before plan_init — where
+ * prior knowledge matters most.
+ *
+ * No model call, no usage: the job's only cost is one embedding pass over
+ * the warm singleton (tens–~200ms) plus a brute-force cosine scan. It still
+ * carries a JobRecord (kind "graph-context") so the dock shows it, and it
+ * registers its AbortController so the dock's END kills it — but an abort
+ * steers NOTHING: nothing was ever promised in the lesson (the injection is
+ * server-initiated scaffolding, unlike a teacher-dispatched sub-agent).
+ *
+ * The topic gate is structural: injection fires only while the session has
+ * EXACTLY ONE text-bearing user message — the topic. Old in-flight sessions
+ * (several typed messages) never inject (no retroactive injection), and a
+ * session whose first turn happened with injection off stays off even if
+ * the budget is raised later (set per-session, before the session starts).
+ */
+
+import {
+	buildGraphContextSteer,
+	steerDelivered,
+	type JobRecord,
+	type SteerMessage,
+} from "../../core/contracts.ts";
+import {
+	GRAPH_CONTEXT_TOKENS_DEFAULT,
+	type ChatSettings,
+} from "../../core/contracts/chat.ts";
+import { hasContext, selectGraphContext } from "../../core/graph-context.ts";
+import type { UIMessage } from "ai";
+import { registerJobAbort, unregisterJobAbort } from "./aborts.ts";
+import type { ChatStore, GraphStore, JobStore } from "../../core/ports.ts";
+
+/** The embedder as the runner needs it: the model/dim the ledger must
+ *  match (parity: one vector space) + the query seam. Injected so tests
+ *  run without the transformer model. */
+export interface GraphContextEmbedder {
+	model: string;
+	dim: number;
+	embedQuery: (text: string) => Promise<number[]>;
+}
+
+export interface GraphContextDeps {
+	chatStore: Pick<ChatStore, "getChat">;
+	jobStore: Pick<JobStore, "createJob" | "getJob" | "updateJob" | "findJobByToolCallId">;
+	graphStore: Pick<GraphStore, "readNodes" | "readEvents" | "readEmbeddings">;
+	embedder: GraphContextEmbedder;
+	/** The wake seam — jobs.ts deliverJobResult (resolves on delivery). */
+	deliver: (steer: SteerMessage) => Promise<void>;
+}
+
+/** The injection job's synthetic toolCallId — no tool part exists; the id
+ *  is deterministic per chat so findJobByToolCallId doubles as the one-shot
+ *  guard, mirroring the spawn-dedup the tool jobs get for free. */
+export function contextToolCallId(chatId: string): string {
+	return `ctx_${chatId}`;
+}
+
+/** The session's effective budget: settings override, else the default.
+ *  Absent ≠ 0 — the decided default is ON (1024 tokens). */
+export function effectiveContextBudget(settings: ChatSettings | undefined): number {
+	return settings?.graphContextTokens ?? GRAPH_CONTEXT_TOKENS_DEFAULT;
+}
+
+/** The session's topic: its ONLY text-bearing user message, if exactly one
+ *  exists. Steers (verdicts, handoffs, answers) carry no text part, so
+ *  quiz rounds during probing never break the gate. */
+export function topicOf(messages: UIMessage[]): string | null {
+	let topic: string | null = null;
+	let count = 0;
+	for (const m of messages) {
+		if (m.role !== "user") continue;
+		const text = m.parts
+			.filter((p) => p.type === "text")
+			.map((p) => (p as { text?: unknown }).text)
+			.filter((t): t is string => typeof t === "string" && t.trim().length > 0)
+			.join("\n");
+		if (text.length === 0) continue;
+		count++;
+		topic = text;
+	}
+	return count === 1 ? topic : null;
+}
+
+/**
+ * The one-shot trigger (fire-and-forget, called from turn-service at every
+ * turn's onFinish): starts the injection job if and only if the session is
+ * at its start (exactly one typed message — the topic), the budget is on,
+ * and nothing was injected before (delivered steer OR any prior context
+ * job — success or failure: one shot means one shot). Returns the created
+ * job for tests; null when nothing was started.
+ */
+export function startGraphContextInjection(deps: GraphContextDeps, chatId: string): JobRecord | null {
+	const { chatStore, jobStore } = deps;
+	const chat = chatStore.getChat(chatId);
+	if (!chat) return null;
+	if (effectiveContextBudget(chat.settings) <= 0) return null;
+	if (topicOf(chat.messages) === null) return null;
+	// One per chat, ever: a delivered steer OR a prior job (any status).
+	if (steerDelivered(chat.messages, `steer_ctx_${chatId}`)) return null;
+	if (jobStore.findJobByToolCallId(chatId, contextToolCallId(chatId))) return null;
+
+	const job = jobStore.createJob({
+		kind: "graph-context",
+		chatId,
+		toolCallId: contextToolCallId(chatId),
+		activity: "searching knowledge graph",
+	});
+	void runGraphContextJob(deps, job.id).catch((err: unknown) => {
+		console.error(`[chat ${chatId}] graph-context injection crashed:`, err);
+	});
+	return job;
+}
+
+/** Run one injection job to completion (background; never throws). Also the
+ *  crash-recovery respawn seam: a job record orphaned "running" by a
+ *  process crash re-runs from here (the record is the only input needed). */
+export async function runGraphContextJob(deps: GraphContextDeps, jobId: string): Promise<void> {
+	const { chatStore, jobStore, graphStore, embedder, deliver } = deps;
+	const job = jobStore.getJob(jobId);
+	if (!job || job.status !== "running") return;
+
+	const fail = (reason: string) => {
+		jobStore.updateJob(jobId, { status: "error", error: reason, activity: "failed" });
+	};
+	const chat = chatStore.getChat(job.chatId);
+	if (!chat) return fail(`chat not found: ${job.chatId}`);
+	const topic = topicOf(chat.messages);
+	if (topic === null) return fail("no injectable topic (session past its start)");
+	const budget = effectiveContextBudget(chat.settings);
+
+	// Real-kill wiring: the dock's END fires this controller; the runner
+	// checks it before every phase transition and unwinds silently.
+	const controller = new AbortController();
+	registerJobAbort(jobId, controller);
+	try {
+		jobStore.updateJob(jobId, { activity: "embedding topic" });
+		const ledger = graphStore.readEmbeddings();
+		if (ledger.model !== embedder.model || ledger.dim !== embedder.dim) {
+			return fail("embeddings ledger is stale (model/dim mismatch) — injection skipped");
+		}
+		if (Object.keys(ledger.vectors).length === 0) {
+			return fail("the knowledge graph has no embeddings yet — nothing to inject");
+		}
+		const query = await embedder.embedQuery(topic);
+		if (controller.signal.aborted) return;
+
+		jobStore.updateJob(jobId, { activity: "selecting propositions" });
+		const data = selectGraphContext({
+			chatId: job.chatId,
+			query,
+			vectors: ledger.vectors,
+			nodes: graphStore.readNodes(),
+			events: graphStore.readEvents(),
+			budget,
+		});
+		if (!hasContext(data)) return fail("nothing relevant fit the budget");
+		if (controller.signal.aborted) return;
+
+		// The result rides the record (crash recovery re-delivers it); the
+		// wake pipeline flips the job done when the lesson has resumed.
+		jobStore.updateJob(jobId, { result: data, activity: "delivering context" });
+		try {
+			await deliver(buildGraphContextSteer({ chatId: job.chatId, jobId }, data));
+		} catch (err) {
+			console.error(`[chat ${job.chatId}] graph-context steer delivery failed:`, err);
+			fail("context delivery failed");
+		}
+	} catch (err) {
+		if (controller.signal.aborted) return; // the abort path owns the record
+		console.error(`[chat ${job.chatId}] graph-context injection failed:`, err);
+		fail(err instanceof Error ? err.message : String(err));
+	} finally {
+		unregisterJobAbort(jobId);
+	}
+}
\ No newline at end of file
diff --git a/src/agent/subagents/runner.ts b/src/agent/subagents/runner.ts
index 9247097..82d1b88 100644
--- a/src/agent/subagents/runner.ts
+++ b/src/agent/subagents/runner.ts
@@ -89,11 +89,14 @@ interface LoopContext {
  * table mirrors MODELS in config.ts (research→researcher, demo→demoBuilder,
  * visual→visualMaker); the id is taken from config so a price-table sync
  * re-prices jobs for free. Model overrides (tests) still bill under the
- * configured model — usage is what is being captured, not which instance. */
+ * configured model — usage is what is being captured, not which instance.
+ * Context-injection jobs make NO model call ("" — onUsage never fires for
+ * them; the kind is deliberately absent from the runners below). */
 const KIND_MODEL: Record<JobKind, string> = {
 	research: MODELS.researcher.model,
 	demo: MODELS.demoBuilder.model,
 	visual: MODELS.visualMaker.model,
+	"graph-context": "",
 };
 
 export function createJobRunner(deps: JobRunnerDeps): JobRunner {
@@ -128,11 +131,15 @@ export function createJobRunner(deps: JobRunnerDeps): JobRunner {
 		return jobStore.getJob(jobId)?.status === "running";
 	}
 
-	/** The kind→runner map: one sub-agent loop per job kind. */
+	/** The kind→runner map: one sub-agent loop per SUB-AGENT kind.
+	 *  graph-context is deliberately absent: injection jobs are not
+	 *  sub-agent loops (no model, graph deps instead) — their spawn and
+	 *  crash-respawn seam is subagents/graph-context.ts, and runJob refuses
+	 *  them below rather than guessing wrong. */
 	// Each kind's runner narrows the union input itself (dispatch-time inputs
 	// are kind-correct by construction; transcript fallbacks are cast after).
 	const KIND_RUNNERS: Record<
-		JobKind,
+		Exclude<JobKind, "graph-context">,
 		(jobId: string, input: JobToolInput | undefined, loop: LoopContext) => Promise<void>
 	> = {
 		research: (jobId, input, loop) => runResearchJob(jobId, researchModelOverride.current, input, loop),
@@ -147,6 +154,12 @@ export function createJobRunner(deps: JobRunnerDeps): JobRunner {
 			return;
 		}
 		if (job.status !== "running") return; // already finished / re-run after crash recovery
+		if (job.kind === "graph-context") {
+			// Not a sub-agent: the injection's own respawn seam
+			// (setContextRespawn → runGraphContextJob) owns these records.
+			console.error(`[job ${jobId}] graph-context job reached the sub-agent runner — wrong seam`);
+			return;
+		}
 		const run = KIND_RUNNERS[job.kind];
 		if (!run) {
 			console.error(`[job ${jobId}] unknown kind: ${job.kind}`);
diff --git a/src/core/contracts/chat.ts b/src/core/contracts/chat.ts
index 683bd19..b53895d 100644
--- a/src/core/contracts/chat.ts
+++ b/src/core/contracts/chat.ts
@@ -10,7 +10,7 @@ import type { UIMessage } from "ai";
 import type { ThinkingLevel } from "@earendil-works/pi-agent-core";
 import type { Phase3 } from "../phases.ts";
 import type { PlanNodeStatus, PlanTree } from "./plan.ts";
-import type { EmissionStats } from "./graph.ts";
+import type { EmissionStats, UnderstandingLevel } from "./graph.ts";
 
 // ─── Chat records (the session store's on-disk format) ───────────────────────
 
@@ -58,8 +58,23 @@ export interface ChatSettings {
 	/** pi thinking level — must be in the chosen model's supported list
 	 *  (getSupportedThinkingLevels; enforced by the settings route). */
 	thinkingLevel?: ThinkingLevel;
+	/** Graph context injection (vision-context-injection.md): the session's
+	 *  token budget for the prior-knowledge block — the top semantically
+	 *  closest propositions from the knowledge graph, injected once, at
+	 *  session start, as a steer. Absent = the default (on); 0 = off. The
+	 *  settings route enforces the range; the trigger (turn-service →
+	 *  subagents/graph-context.ts) is one-shot, so a mid-session change
+	 *  affects only sessions that haven't injected yet. */
+	graphContextTokens?: number;
 }
 
+/** The injection budget's decided knobs (2026-09-14): default 1024 (a
+ *  meaningful, modest slice of prior knowledge), hard max 4096, slider
+ *  step 128, 0 = off. */
+export const GRAPH_CONTEXT_TOKENS_DEFAULT = 1024;
+export const GRAPH_CONTEXT_TOKENS_MAX = 4096;
+export const GRAPH_CONTEXT_TOKENS_STEP = 128;
+
 // ─── Background-extraction usage (the money channel, extraction side) ────────
 
 /** One pipeline stage's model usage — the stage's model + every step it
@@ -176,6 +191,54 @@ export const HANDOFF_TEXT =
 	"The probe is concluded — the learner assessment is recorded. " +
 	"Author the session's plan map now (call plan_init) and present it, then begin teaching.";
 
+// ─── Graph context injection (vision-context-injection.md, 2026-09-14) ────────
+
+/** One selected prior-knowledge proposition: similarity-ranked, annotated
+ *  with the learner's CURRENT understanding level — the fold is MOST
+ *  RECENT extraction instance (levels are per-instance, tied to moments in
+ *  time; the latest evidence is the best estimate of current understanding).
+ *  null = the node has no observation event at all. */
+export interface GraphContextProposition {
+	id: string;
+	statement: string;
+	level: UnderstandingLevel | null;
+}
+
+/** The data-graph-context part payload: what the UI renders (the counts)
+ *  AND the audit trail (the full block content — the transcript shows
+ *  exactly what was injected, and when). The model-facing text is derived
+ *  from this by graphContextText below — the adapter flattens the marker
+ *  part to it (the custom-message scheme: no authored human speech). */
+export interface GraphContextData {
+	chatId: string;
+	/** The session's budget at injection time (for the card's readout). */
+	budget: number;
+	/** Estimated tokens of the injected block — chars/4 heuristic. */
+	tokens: number;
+	/** The selected propositions, similarity-descending. */
+	propositions: GraphContextProposition[];
+}
+
+/** The model-facing block text — single-sourced (the adapter, the tests,
+ *  and reality can't drift). The level word travels with each line: the
+ *  closing gloss tells the agent what to do with each. */
+export function graphContextText(data: GraphContextData): string {
+	const n = data.propositions.length;
+	if (n === 0) return "";
+	const lines = data.propositions.map(
+		(p) => `- ${p.level ? `[${p.level}] ` : ""}${p.statement}`,
+	);
+	return [
+		`Prior-knowledge context — what this learner already knows (from their knowledge graph, ` +
+			`${n} proposition${n === 1 ? "" : "s"}, ~${data.tokens} tokens):`,
+		"",
+		...lines,
+		"",
+		"Treat this as reliable prior knowledge: build on what is solid, firm up what is shaky, " +
+			"and teach around anything resisted. Do not re-teach solid ground.",
+	].join("\n");
+}
+
 export interface PlanBlockData {
 	/** Only "full" survives (the 2026-09-11 pivot): the plan renders IN
 	 *  FLOW once, at authoring. The neighborhood fragments are retired —
diff --git a/src/core/contracts/jobs.ts b/src/core/contracts/jobs.ts
index f617ebf..25d1db1 100644
--- a/src/core/contracts/jobs.ts
+++ b/src/core/contracts/jobs.ts
@@ -7,11 +7,11 @@
  * of "ai" (safe everywhere: server, client, tests). See docs/vision.md.
  */
 import type { UIMessage } from "ai";
-import type { CallUsage } from "./chat.ts";
+import type { CallUsage, GraphContextData } from "./chat.ts";
 
 // ─── Async sub-agent jobs (vision §2.5; plan.md Wave 0 protocol) ────────────
 
-export type JobKind = "research" | "demo" | "visual";
+export type JobKind = "research" | "demo" | "visual" | "graph-context";
 export type JobStatus = "running" | "done" | "error";
 
 export interface JobRecord {
@@ -263,7 +263,11 @@ export interface AbortSteerMessage extends UIMessage {
 }
 
 /** Anything the wake pipeline may queue and deliver. */
-export type SteerMessage = SubagentSteerMessage | AbortSteerMessage | ProbeHandoffSteerMessage;
+export type SteerMessage =
+	| SubagentSteerMessage
+	| AbortSteerMessage
+	| ProbeHandoffSteerMessage
+	| GraphContextSteerMessage;
 
 /** Whether a result is the failure shape (html/svg empty, failure brief). */
 export function isSubagentFailure(kind: JobKind, result: ResearchResult | DemoResult | VisualResult): boolean {
@@ -380,6 +384,34 @@ export function buildProbeHandoffSteer(chatId: string): ProbeHandoffSteerMessage
 	};
 }
 
+// ─── the graph-context steer (vision-context-injection.md) ───────────────────
+//
+// The injection's delivery: same wake pipeline, same gates — it queues
+// behind a pending quiz and rides the turn after the learner's answer, or
+// fires in the pump's idle window. Marker-only (the custom-message scheme):
+// no text part; the adapter flattens data-graph-context to graphContextText
+// (core/contracts/chat.ts owns the wording). One per chat, ever — the id is
+// deterministic per chat, so re-delivery is idempotent.
+
+export interface GraphContextSteerMessage extends UIMessage {
+	id: `steer_ctx_${string}`;
+	role: "user";
+	metadata: { graphContext: { chatId: string; jobId: string } };
+	parts: [{ type: "data-graph-context"; data: GraphContextData }];
+}
+
+export function buildGraphContextSteer(
+	meta: { chatId: string; jobId: string },
+	data: GraphContextData,
+): GraphContextSteerMessage {
+	return {
+		id: `steer_ctx_${meta.chatId}`,
+		role: "user",
+		metadata: { graphContext: meta },
+		parts: [{ type: "data-graph-context", data }],
+	};
+}
+
 /** True when the transcript already carries this steer — idempotent
  *  delivery for ANY steer kind: every steer id is deterministic per its
  *  event (steer_<jobId> for jobs, steer_probe_<chatId> for the handoff). */
diff --git a/src/core/graph-context.ts b/src/core/graph-context.ts
new file mode 100644
index 0000000..cd79e99
--- /dev/null
+++ b/src/core/graph-context.ts
@@ -0,0 +1,184 @@
+/**
+ * Graph context injection — the pure selection core
+ * (docs/vision-context-injection.md, settled 2026-09-14).
+ *
+ * The heavy lifting is deliberately tiny: embedding the topic is the only
+ * slow step (the embedder singleton), and SEARCH IS BRUTE-FORCE COSINE —
+ * ~1M multiply-adds at 2k propositions, exact top-K from the in-memory
+ * ledger, no ANN index until ~10⁶ scale (far away).
+ *
+ * Selection doctrine (owner-decided): the token budget is the ONLY control
+ * on amount — there is NO similarity threshold. Similarity decides ORDER
+ * (which propositions fill the budget first); irrelevant-but-cheap content
+ * rides along harmlessly. Levels fold MOST RECENT: UnderstandingLevel lives
+ * per extraction instance (tied to moments in time), and the latest evidence
+ * is the best estimate of current understanding — an optimistic fold risks
+ * stale claims, a pessimistic fold wastes covered ground.
+ */
+
+
+import {
+	GRAPH_CONTEXT_TOKENS_MAX,
+	type GraphContextData,
+	type GraphContextProposition,
+	graphContextText,
+} from "./contracts/chat.ts";
+import type { UnderstandingLevel } from "./contracts/graph.ts";
+import type { GraphNode, LedgerEvent } from "./contracts/graph.ts";
+
+/** Belt-and-braces count cap — the budget is the primary control; a huge
+ *  budget still can't pour hundreds of lines into the block. */
+export const GRAPH_CONTEXT_MAX_PROPOSITIONS = 64;
+
+/** The block's framing (header + gloss) in estimated tokens — reserved so
+ *  the composed block, not just the proposition lines, stays under budget. */
+const FRAMING_TOKENS = 55;
+
+const LEVELS: ReadonlySet<string> = new Set([
+	"solid",
+	"shaky",
+	"accepted",
+	"resisted",
+	"not yet engaged",
+]);
+
+export function isUnderstandingLevel(word: unknown): word is UnderstandingLevel {
+	return typeof word === "string" && LEVELS.has(word);
+}
+
+/**
+ * Fold each node's CURRENT understanding level: the level word of its most
+ * recent observation event (latest `at`; ledger order breaks ties — the
+ * same rule the snapshot's nodeObservations uses, but across ALL sessions,
+ * not per chat). Malformed notes (not on the scale) never count.
+ */
+export function currentUnderstanding(events: LedgerEvent[]): Map<string, UnderstandingLevel> {
+	const latest = new Map<string, { at: string; level: UnderstandingLevel; index: number }>();
+	events.forEach((event, index) => {
+		if (event.kind !== "observation" || event.nodeId === null) return;
+		if (!isUnderstandingLevel(event.note)) return;
+		const current = latest.get(event.nodeId);
+		if (!current || event.at > current.at || (event.at === current.at && index > current.index)) {
+			latest.set(event.nodeId, { at: event.at, level: event.note, index });
+		}
+	});
+	const levels = new Map<string, UnderstandingLevel>();
+	for (const [nodeId, { level }] of latest) levels.set(nodeId, level);
+	return levels;
+}
+
+/** Estimated tokens for one proposition line: chars/4 (the agreed
+ *  heuristic — no server-side tokenizer) + one for the level tag. */
+function lineTokens(p: GraphContextProposition): number {
+	return Math.ceil(p.statement.length / 4) + (p.level ? 1 : 0);
+}
+
+export interface SelectGraphContextInput {
+	chatId: string;
+	/** The topic's query embedding (same model + dim as the ledger — the
+	 *  caller asserts parity; dimension-mismatched vectors are skipped). */
+	query: number[];
+	/** The embeddings ledger's vectors: nodeId → truncated, L2-normalized
+	 *  (cosine = dot product). */
+	vectors: Record<string, number[]>;
+	/** Raw node lines (append order; first line per id defines — the
+	 *  ledger merge rule, mirrored from core/graph.ts). */
+	nodes: GraphNode[];
+	/** The event ledger — for the most-recent level fold. */
+	events: LedgerEvent[];
+	/** The session's token budget (estimated tokens, chars/4). */
+	budget: number;
+}
+
+/**
+ * Select the prior-knowledge block: similarity-descending greedy fill under
+ * the token budget, capped by count, each line annotated with its folded
+ * current level. Pure — server composes it with the embedder; tests drive
+ * it with hand-made vectors.
+ */
+export function selectGraphContext(input: SelectGraphContextInput): GraphContextData {
+	const { chatId, query, vectors, nodes, events, budget } = input;
+	const levels = currentUnderstanding(events);
+
+	// Score every embedded node: dot product (vectors are normalized). A
+	// dimension mismatch (a stale ledger, a foreign query) never scores.
+	const scored: Array<{ id: string; statement: string; score: number }> = [];
+	const seen = new Set<string>();
+	for (const node of nodes) {
+		if (seen.has(node.id)) continue; // first line defines (merge rule)
+		seen.add(node.id);
+		const vec = vectors[node.id];
+		if (!vec || vec.length !== query.length) continue;
+		let dot = 0;
+		for (let i = 0; i < query.length; i++) dot += query[i]! * vec[i]!;
+		scored.push({ id: node.id, statement: node.statement, score: dot });
+	}
+	scored.sort((a, b) => b.score - a.score || a.id.localeCompare(b.id));
+
+	// Greedy fill: similarity order decides WHICH propositions enter; the
+	// budget decides WHEN to stop. No similarity threshold, by design.
+	const propositions: GraphContextProposition[] = [];
+	let used = FRAMING_TOKENS;
+	for (const { id, statement } of scored) {
+		if (propositions.length >= GRAPH_CONTEXT_MAX_PROPOSITIONS) break;
+		const p: GraphContextProposition = {
+			id,
+			statement,
+			level: levels.get(id) ?? null,
+		};
+		const cost = lineTokens(p);
+		if (used + cost > budget) continue; // too big for the budget — a later, smaller one may still fit
+		used += cost;
+		propositions.push(p);
+	}
+	return { chatId, budget, tokens: used, propositions };
+}
+
+/** True when the selection would inject anything (guards the runner: an
+ *  empty block is never delivered — no steer, the job errors instead). */
+export function hasContext(data: GraphContextData): boolean {
+	return data.propositions.length > 0 && graphContextText(data).length > 0;
+}
+
+// ─── The marker-part parser (parse-don't-cast — tool-parts doctrine) ──────────
+
+function parseProposition(raw: unknown): GraphContextProposition | null {
+	if (typeof raw !== "object" || raw === null) return null;
+	const { id, statement, level } = raw as Record<string, unknown>;
+	if (typeof id !== "string" || typeof statement !== "string") return null;
+	if (level !== null && level !== undefined && !isUnderstandingLevel(level)) return null;
+	return { id, statement, level: (level as UnderstandingLevel | null | undefined) ?? null };
+}
+
+function parseGraphContextData(raw: unknown): GraphContextData | null {
+	if (typeof raw !== "object" || raw === null) return null;
+	const { chatId, budget, tokens, propositions } = raw as Record<string, unknown>;
+	if (typeof chatId !== "string") return null;
+	if (typeof budget !== "number" || budget < 0 || budget > GRAPH_CONTEXT_TOKENS_MAX) return null;
+	if (typeof tokens !== "number" || tokens < 0) return null;
+	if (!Array.isArray(propositions)) return null;
+	const parsed: GraphContextProposition[] = [];
+	for (const item of propositions) {
+		const p = parseProposition(item);
+		if (!p) return null; // malformed content: the whole part is untrusted
+		parsed.push(p);
+	}
+	return { chatId, budget, tokens, propositions: parsed };
+}
+
+/**
+ * The data-graph-context part of a message, validated — or null when the
+ * part is absent or malformed. The seam the adapter and the chat view read
+ * the marker through (never a raw cast: the part's data crossed a
+ * serialization boundary).
+ */
+export function graphContextOfMessage(
+	message: { parts: ReadonlyArray<{ type: string; data?: unknown }> },
+): GraphContextData | null {
+	for (const part of message.parts) {
+		if (part.type === "data-graph-context") {
+			return parseGraphContextData((part as { data?: unknown }).data);
+		}
+	}
+	return null;
+}
\ No newline at end of file
diff --git a/src/core/index.ts b/src/core/index.ts
index 5e1a4bf..753794b 100644
--- a/src/core/index.ts
+++ b/src/core/index.ts
@@ -34,3 +34,4 @@ export * from "./ui-message.ts";
 export * from "./tool-parts.ts";
 export * from "./prices.ts";
 export * from "./fuzzy.ts";
+export * from "./graph-context.ts";
diff --git a/src/core/ui-message.ts b/src/core/ui-message.ts
index 807d103..f2b4258 100644
--- a/src/core/ui-message.ts
+++ b/src/core/ui-message.ts
@@ -1,6 +1,7 @@
 import type { UIMessage } from "ai";
 import type {
 	DemoToolInput,
+	GraphContextData,
 	PlanVerdictData,
 	PlanBlockData,
 	ProbeDoneInput,
@@ -46,6 +47,10 @@ export type TeacherUIDataParts = {
 	/** The probe→teach handoff wake: the wake pipeline's steer message,
 	 *  carrying ONLY this part (the model-facing text lives in the adapter). */
 	"probe-handoff": { chatId: string };
+	/** The prior-knowledge injection's delivery (vision-context-injection.md):
+	 *  the marker-only steer — the counts for the UI, the full block content
+	 *  for the audit trail; the adapter flattens it to graphContextText. */
+	"graph-context": GraphContextData;
 	/** The abort steer's message-type marker (the abort badge renders off it). */
 	"subagent-aborted": SubagentResultMeta & { aborted: true };
 };
diff --git a/src/server/chat-handler.ts b/src/server/chat-handler.ts
index a160b9f..b1969c9 100644
--- a/src/server/chat-handler.ts
+++ b/src/server/chat-handler.ts
@@ -4,14 +4,15 @@ import { createProberAgent, createTeacherAgent, type TeachingAgent } from "../ag
 import { piEngineFor } from "../agent/models.ts";
 import { createJobRunner } from "../agent/subagents/runner.ts";
 import { createExtractionPipeline } from "../agent/subagents/extraction.ts";
-import { embedNewNodes } from "./embeddings.ts";
+import { runGraphContextJob, type GraphContextDeps } from "../agent/subagents/graph-context.ts";
+import { EMBEDDING_DIM, EMBEDDING_MODEL, embedNewNodes, embedQuery } from "./embeddings.ts";
 import type { ModelRole } from "../../config.ts";
-import { claimSteers, deliverJobResult, setJobRespawn, setTurnRunner } from "./jobs.ts";
+import { claimSteers, deliverJobResult, setContextRespawn, setJobRespawn, setTurnRunner } from "./jobs.ts";
 import { recordToPiMessages } from "./pi/record-adapter.ts";
 import { createPiTurnResponse } from "./pi/ui-stream.ts";
 import { stores } from "./stores.ts";
 import { beginTurn, endTurn } from "./turn-liveness.ts";
-import { persistTurn, triggerExtraction, withMessageIds } from "./turn-service.ts";
+import { persistTurn, triggerExtraction, triggerGraphContext, withMessageIds } from "./turn-service.ts";
 import type { CallUsage } from "../core/contracts.ts";
 
 /**
@@ -48,6 +49,18 @@ export const extraction = createExtractionPipeline({
 	embedder: embedNewNodes,
 });
 
+/** Graph context injection (vision-context-injection.md): the runner's
+ *  deps — same storage ports, the REAL embedder as the query seam (same
+ *  warm singleton as extraction, so vector-space parity holds by
+ *  construction), and the wake pipeline as the delivery seam. */
+export const graphContext: GraphContextDeps = {
+	chatStore: stores.chatStore,
+	jobStore: stores.jobStore,
+	graphStore: stores.graphStore,
+	embedder: { model: EMBEDDING_MODEL, dim: EMBEDDING_DIM, embedQuery },
+	deliver: deliverJobResult,
+};
+
 // Wake-pipeline wiring (contracts.ts "THE ASYNC PROTOCOL" §4): the pipeline
 // fires its server-side teacher turns through THIS composition root, and
 // crash recovery re-spawns orphaned sub-agent loops through THIS runner.
@@ -65,6 +78,7 @@ setTurnRunner(async (chatId, messages) => {
 	return res.status;
 });
 setJobRespawn((jobId) => void jobRunner.runJob(jobId));
+setContextRespawn((jobId) => void runGraphContextJob(graphContext, jobId));
 
 /** The message-shape gate the SDK's UIMessageValidator owned: a malformed
  *  body must fail BEFORE the stream exists — the path where no onFinish will
@@ -223,6 +237,9 @@ export async function handleChatRequest(
 					});
 				}
 				triggerExtraction(stores, extraction, chatId);
+				// The graph READ channel: one-shot prior-knowledge injection at
+				// session start — a no-op for every session past its start.
+				triggerGraphContext(graphContext, chatId);
 				// LAST: a poller that sees not-in-flight must read an already-persisted
 				// record — endTurn only after persistTurn has done its job.
 				endTurn(chatId);
diff --git a/src/server/embeddings.ts b/src/server/embeddings.ts
index 0d9194f..1bb6091 100644
--- a/src/server/embeddings.ts
+++ b/src/server/embeddings.ts
@@ -42,6 +42,24 @@ function embedInput(statement: string): string {
 	return `title: none | text: ${statement}`;
 }
 
+/** EmbeddingGemma's retrieval-QUERY format (model card) — the topic side of
+ *  graph context injection (vision-context-injection.md). Role-asymmetric
+ *  BY DESIGN: queries and documents use different trained templates; the
+ *  requirement is same model + same truncation (one vector space), each
+ *  side in the format the model was trained for. */
+function queryInput(text: string): string {
+	return `task: search result | query: ${text}`;
+}
+
+/** Embed one retrieval query (the session's topic) — same warm singleton,
+ *  same 512-dim MRL truncation as the ledger. The one embedding call the
+ *  injection job makes; tens–~200ms warm. */
+export async function embedQuery(text: string): Promise<number[]> {
+	const extractor = await getPipeline();
+	const output = await extractor([queryInput(text)], { pooling: "mean", normalize: true });
+	return truncateNormalize((output.tolist() as number[][])[0]!);
+}
+
 /** Truncate an L2-normalized vector to EMBEDDING_DIM (MRL: leading dims
  *  carry most of the signal) and re-normalize so cosine = dot product. */
 function truncateNormalize(vec: readonly number[]): number[] {
diff --git a/src/server/jobs.ts b/src/server/jobs.ts
index 3adf096..aab8518 100644
--- a/src/server/jobs.ts
+++ b/src/server/jobs.ts
@@ -34,6 +34,7 @@
 import type { UIMessage } from "ai";
 import {
 	buildAbortSteer,
+	buildGraphContextSteer,
 	buildSubagentSteer,
 	isSubagentFailure,
 	steerDelivered,
@@ -60,6 +61,9 @@ interface QueuedSteer {
 interface WakeState {
 	turnRunner?: TurnRunner;
 	respawn?: JobRespawn;
+	/** Crash recovery for context-injection jobs (they are not sub-agent
+	 *  loops — their runner takes the graph deps; chat-handler wires it). */
+	contextRespawn?: (jobId: string) => void;
 	/** chatId → steers awaiting delivery, in arrival order. */
 	queues: Map<string, QueuedSteer[]>;
 	/** Chats whose pump loop is currently active (serialization per chat). */
@@ -87,6 +91,13 @@ export function setJobRespawn(respawn: JobRespawn): void {
 	state().respawn = respawn;
 }
 
+/** chat-handler wires this at module init: the graph-context runner
+ *  (subagents/graph-context.ts runGraphContextJob — re-runnable from the
+ *  job record alone, which is all crash recovery has). */
+export function setContextRespawn(respawn: (jobId: string) => void): void {
+	state().contextRespawn = respawn;
+}
+
 const POLL_MS = 400;
 /** After the gates open, wait a beat before firing — a client that just
  *  answered a question is about to send its continuation; don't 409 it.
@@ -110,11 +121,14 @@ function delay(ms: number): Promise<void> {
 	return new Promise((resolve) => setTimeout(resolve, ms));
 }
 
-/** The job a steer belongs to, if it is a job steer (result/abort);
+/** The job a steer belongs to, if it is a job steer (result/abort/context);
  *  probe-handoff steers have no job — null. */
 function jobIdOf(steer: SteerMessage): string | null {
-	const meta = steer.metadata as { subagentResult?: { jobId: string } };
-	return meta.subagentResult?.jobId ?? null;
+	const meta = steer.metadata as {
+		subagentResult?: { jobId: string };
+		graphContext?: { jobId: string };
+	};
+	return meta.subagentResult?.jobId ?? meta.graphContext?.jobId ?? null;
 }
 
 /** Finalize a delivered steer's job bookkeeping — job steers only. */
@@ -220,6 +234,12 @@ export function abortJob(jobId: string): AbortOutcome {
 	if (!job) return { ok: false, reason: "not_found" };
 	if (job.status !== "running") return { ok: false, reason: "not_running" };
 
+	// Context-injection jobs abort SILENTLY: nothing was ever promised in the
+	// lesson (server-initiated scaffolding, unlike a teacher-dispatched
+	// sub-agent), so no abort steer — flipping the record and killing the
+	// run is the whole story. Steps 1–3 below are shared; step 4 is skipped.
+	const isContext = job.kind === "graph-context";
+
 	fireJobAbort(jobId); // no-op when the loop already returned (delivering)
 
 	// Drop any queued steers for this job (their deliver() resolves unfired).
@@ -234,16 +254,22 @@ export function abortJob(jobId: string): AbortOutcome {
 	}
 
 	stores.jobStore.updateJob(jobId, { status: "error", error: "Aborted by learner", activity: "aborted" });
-	void deliverJobResult(buildAbortSteer(job)).catch(() => {
-			/* deliverJobResult marks the job error on unrecoverable failure */
-	});
+	if (!isContext) {
+		void deliverJobResult(buildAbortSteer(job)).catch(() => {
+				/* deliverJobResult marks the job error on unrecoverable failure */
+		});
+	}
 	return { ok: true };
 }
 
 function chatIdOf(steer: SteerMessage): string {
-	// The probe handoff carries its chat directly (no job record exists).
+	// The probe handoff and the context injection carry their chat directly
+	// (the context steer's job record would say it too, but the metadata is
+	// the cheap path — same rule as the handoff).
 	const handoff = (steer.metadata as { probeHandoff?: { chatId: string } }).probeHandoff;
 	if (handoff) return handoff.chatId;
+	const injected = (steer.metadata as { graphContext?: { chatId: string } }).graphContext;
+	if (injected) return injected.chatId;
 	// The chat is resolvable from the job record; the steer's metadata
 	// carries jobId, which indexes the store.
 	const jobId = jobIdOf(steer);
@@ -352,6 +378,12 @@ async function pump(chatId: string): Promise<void> {
 function finalizeJob(jobId: string): void {
 	const job = stores.jobStore.getJob(jobId);
 	if (!job || job.status !== "running") return;
+	// Context-injection jobs have no sub-agent result shape — a delivered
+	// block is a success, full stop (isSubagentFailure would misread it).
+	if (job.kind === "graph-context") {
+		stores.jobStore.updateJob(jobId, { status: "done", activity: "delivered" });
+		return;
+	}
 	const result = job.result;
 	const failed = result ? isSubagentFailure(job.kind, result as never) : true;
 	stores.jobStore.updateJob(jobId, {
@@ -418,6 +450,23 @@ function recoverStaleJobs(): void {
 				if (now - Date.parse(job.updatedAt) < STALE_JOB_MS) continue;
 				if (!stores.chatStore.getChat(job.chatId)) continue;
 				if (isTurnRunning(job.chatId)) continue; // a wake turn may be delivering it right now
+				if (job.kind === "graph-context") {
+					// Context-injection orphans: a stored block re-delivers in its own
+					// steer shape; a job that died before selecting re-runs from the
+					// record (the graph runner — not the sub-agent respawn seam).
+					if (job.result) {
+						stores.jobStore.updateJob(job.id, { activity: "recovering: re-delivering" });
+						void deliverJobResult(
+							buildGraphContextSteer({ chatId: job.chatId, jobId: job.id }, job.result as never),
+						).catch(() => {
+							/* deliverJobResult marks the job error on failure */
+						});
+					} else if (s.contextRespawn) {
+						stores.jobStore.updateJob(job.id, { activity: "recovering: re-running" });
+						s.contextRespawn(job.id);
+					}
+					continue;
+				}
 				if (job.result) {
 					// The wake never fired (or crashed mid-flight): re-deliver.
 					const steer = buildSubagentSteer(job, job.result as never);
diff --git a/src/server/pi/record-adapter.ts b/src/server/pi/record-adapter.ts
index 029324d..f2b193e 100644
--- a/src/server/pi/record-adapter.ts
+++ b/src/server/pi/record-adapter.ts
@@ -1,7 +1,8 @@
 import type { UIMessage } from "ai";
 import type { AgentMessage } from "@earendil-works/pi-agent-core";
 import type { AssistantMessage, Message, ToolResultMessage } from "@earendil-works/pi-ai";
-import { HANDOFF_TEXT, verdictText } from "../../core/contracts/chat.ts";
+import { graphContextOfMessage } from "../../core/graph-context.ts";
+import { graphContextText, HANDOFF_TEXT, verdictText } from "../../core/contracts/chat.ts";
 
 /**
  * The record → pi-ai transcript adapter (docs/pi-engine-swap.md §4). The
@@ -55,12 +56,19 @@ function zeroUsage() {
 
 /** The model-facing text of a marker-only user message, or null when the
  *  message has no model face at all (UI-only data parts). */
-function systemTextOf(parts: ReadonlyArray<{ type: string; data?: unknown }>): string | null {
-	for (const part of parts) {
+function systemTextOf(message: { parts: ReadonlyArray<{ type: string; data?: unknown }> }): string | null {
+	for (const part of message.parts) {
 		if (part.type === "data-verdict") {
 			return verdictText((part.data as { accepted?: unknown } | undefined)?.accepted === true);
 		}
 		if (part.type === "data-probe-handoff") return HANDOFF_TEXT;
+		// Graph context injection: the block text derives from the part's
+		// validated data (parse-don't-cast — a malformed part has no model
+		// face, and the message then never reaches the provider).
+		if (part.type === "data-graph-context") {
+			const data = graphContextOfMessage({ parts: message.parts });
+			return data ? graphContextText(data) : null;
+		}
 	}
 	return null;
 }
@@ -79,7 +87,7 @@ export function recordToPiMessages(messages: UIMessage[]): Message[] {
 			// wording lives in the adapter's reach (core contracts), never
 			// authored as fake human speech in the transcript.
 			if (texts.length === 0) {
-				const flat = systemTextOf(message.parts);
+				const flat = systemTextOf(message);
 				if (flat === null) continue; // pure UI data part, no model face
 				texts.push(flat);
 			}
diff --git a/src/server/turn-service.ts b/src/server/turn-service.ts
index 0733e33..ff120cb 100644
--- a/src/server/turn-service.ts
+++ b/src/server/turn-service.ts
@@ -21,6 +21,7 @@ import { pendingQuizAnswers } from "../core/graph.ts";
 import type { ChatStore, GraphStore } from "../core/ports.ts";
 import { EXTRACTION } from "../../config.ts";
 import type { ExtractionPipeline } from "../agent/subagents/extraction.ts";
+import { startGraphContextInjection, type GraphContextDeps } from "../agent/subagents/graph-context.ts";
 
 /**
  * The canonical state write: the client owns the message list between turns
@@ -98,3 +99,22 @@ export function triggerExtraction(
 		console.error(`[chat ${chatId}] extraction trigger failed:`, err);
 	}
 }
+
+/**
+ * The graph READ channel (vision-context-injection.md): one shot per chat,
+ * at session start — the first typed message is the session's topic; the
+ * semantically closest propositions are selected under the session's token
+ * budget and steered in through the wake pipeline. Fire-and-forget like
+ * triggerExtraction; the one-shot gates (topic, budget, prior injection)
+ * live in the runner module, not here — this seam only decides WHEN to ask.
+ * Skipped under tests, same doctrine: the runner is tested directly with a
+ * scripted embedder.
+ */
+export function triggerGraphContext(deps: GraphContextDeps, chatId: string): void {
+	if (process.env.NODE_ENV === "test") return;
+	try {
+		startGraphContextInjection(deps, chatId);
+	} catch (err) {
+		console.error(`[chat ${chatId}] graph-context trigger failed:`, err);
+	}
+}
diff --git a/tests/graph-context-core.test.ts b/tests/graph-context-core.test.ts
new file mode 100644
index 0000000..cdfb5a3
--- /dev/null
+++ b/tests/graph-context-core.test.ts
@@ -0,0 +1,291 @@
+/**
+ * Graph context injection — the pure core (docs/vision-context-injection.md):
+ * selection doctrine, level fold, block text, the marker-part parser, and
+ * the runner's pure gates (topic/budget/one-shot). Deterministic, zero
+ * network, zero stores — hand-made vectors.
+ */
+
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+import type { UIMessage } from "ai";
+import {
+	buildGraphContextSteer,
+	steerDelivered,
+	GRAPH_CONTEXT_TOKENS_DEFAULT,
+	GRAPH_CONTEXT_TOKENS_MAX,
+	GRAPH_CONTEXT_TOKENS_STEP,
+	graphContextText,
+	type GraphContextData,
+} from "../src/core/contracts.ts";
+import {
+	currentUnderstanding,
+	GRAPH_CONTEXT_MAX_PROPOSITIONS,
+	graphContextOfMessage,
+	hasContext,
+	isUnderstandingLevel,
+	selectGraphContext,
+} from "../src/core/graph-context.ts";
+import {
+	contextToolCallId,
+	effectiveContextBudget,
+	topicOf,
+} from "../src/agent/subagents/graph-context.ts";
+import type { GraphNode, LedgerEvent } from "../src/core/contracts/graph.ts";
+
+function unit(i: number): number[] {
+	const v = new Array(8).fill(0);
+	v[i] = 1;
+	return v;
+}
+
+function node(id: string, statement: string): GraphNode {
+	return {
+		id,
+		name: id,
+		statement,
+		aliases: [],
+		provenance: [],
+		createdAt: "2026-09-14T00:00:00.000Z",
+	};
+}
+
+function obs(nodeId: string, level: string, at: string, chatId = "chat_x"): LedgerEvent {
+	return { nodeId, kind: "observation", chatId, at, note: level };
+}
+
+/** A text-bearing user message (the learner's typed speech). */
+function userText(text: string): UIMessage {
+	return { id: `m_${text.length}`, role: "user", parts: [{ type: "text", text }] };
+}
+
+/** A marker-only user message (steer scaffolding — no text). */
+function marker(type: string, data: unknown): UIMessage {
+	return { id: `m_${type}`, role: "user", parts: [{ type, data } as never] };
+}
+
+describe("currentUnderstanding — the most-recent fold", () => {
+	it("latest observation wins, across chats, ledger order breaks ties", () => {
+		const events = [
+			obs("n1", "shaky", "2026-09-01T00:00:00Z", "chat_a"),
+			obs("n1", "solid", "2026-09-10T00:00:00Z", "chat_b"),
+			obs("n2", "resisted", "2026-09-05T00:00:00Z"),
+			obs("n2", "accepted", "2026-09-05T00:00:00Z"), // same at → later line wins
+		];
+		const levels = currentUnderstanding(events);
+		assert.equal(levels.get("n1"), "solid");
+		assert.equal(levels.get("n2"), "accepted");
+		assert.equal(levels.size, 2);
+	});
+
+	it("off-scale notes never count (the closed list is the only vocabulary)", () => {
+		assert.equal(isUnderstandingLevel("solid"), true);
+		assert.equal(isUnderstandingLevel("pretty good"), false);
+		const levels = currentUnderstanding([obs("n1", "confident", "2026-09-01T00:00:00Z")]);
+		assert.equal(levels.size, 0);
+	});
+
+	it("quiz outcome events and null nodes are not observations", () => {
+		const events: LedgerEvent[] = [
+			{ nodeId: "n1", kind: "correct", chatId: "c", at: "2026-09-01T00:00:00Z" },
+			{ nodeId: null, kind: "observation", chatId: "c", at: "2026-09-01T00:00:00Z", note: "solid" },
+		];
+		assert.equal(currentUnderstanding(events).size, 0);
+	});
+});
+
+describe("selectGraphContext — similarity orders, the budget is the only amount control", () => {
+	const base = {
+		chatId: "chat_1",
+		query: unit(0),
+		events: [] as LedgerEvent[],
+	};
+
+	it("fills similarity-descending and stops before exceeding the budget", () => {
+		const vectors = { a: unit(0), b: unit(0), c: unit(7) };
+		const nodes = [
+			node("a", "Water boils at 100°C at sea level."),
+			node("b", "Evaporation cools the surrounding air."),
+			node("c", "The Schrödinger equation is linear."),
+		];
+		// budget 55 (framing) + ~9 tokens for statement a ≈ fits exactly one line.
+		const data = selectGraphContext({ ...base, vectors, nodes, budget: 66 });
+		assert.deepEqual(
+			data.propositions.map((p) => p.id),
+			["a"],
+		);
+		assert.equal(data.tokens <= 66, true);
+		assert.equal(data.budget, 66);
+	});
+
+	it("an oversized line is skipped, a later smaller one may still fit (no threshold, pure budget)", () => {
+		const vectors = { big: unit(0), small: unit(0), off: unit(7) };
+		const big = "X".repeat(400); // ~100 tokens — bigger than the whole budget
+		const nodes = [
+			node("big", big),
+			node("small", "Ice melts."),
+			node("off", "Irrelevant."),
+		];
+		// budget 60: 'big' (~100 tokens) is skipped outright; 'small' (4 tokens
+		// incl. the level slot + framing 55 = 59) fits; 'off' (63) doesn't.
+		const data = selectGraphContext({ ...base, vectors, nodes, budget: 60 });
+		assert.deepEqual(
+			data.propositions.map((p) => p.id),
+			["small"],
+		);
+	});
+
+	it("annotates each line with the folded current level (null when unobserved)", () => {
+		const vectors = { a: unit(0), b: unit(0) };
+		const nodes = [node("a", "A."), node("b", "B.")];
+		const events = [obs("b", "shaky", "2026-09-10T00:00:00Z")];
+		const data = selectGraphContext({ ...base, vectors, nodes, events, budget: 4096 });
+		const byId = Object.fromEntries(data.propositions.map((p) => [p.id, p]));
+		assert.equal(byId.a!.level, null);
+		assert.equal(byId.b!.level, "shaky");
+	});
+
+	it("the count cap bounds even a huge budget", () => {
+		const vectors: Record<string, number[]> = {};
+		const nodes: GraphNode[] = [];
+		for (let i = 0; i < GRAPH_CONTEXT_MAX_PROPOSITIONS + 10; i++) {
+			const id = `n${i}`;
+			vectors[id] = unit(0);
+			nodes.push(node(id, `Statement ${i}.`));
+		}
+		const data = selectGraphContext({ ...base, vectors, nodes, budget: GRAPH_CONTEXT_TOKENS_MAX });
+		assert.equal(data.propositions.length, GRAPH_CONTEXT_MAX_PROPOSITIONS);
+	});
+
+	it("dimension-mismatched vectors and duplicate node lines are handled", () => {
+		const vectors = { ok: unit(0), stale: [1, 2, 3] };
+		const nodes = [
+			node("ok", "Fine."),
+			node("dup", "First line."),
+			node("dup", "Second line never redefines."),
+		];
+		// "dup" has no vector anyway; the pin is that the scan neither throws
+		// nor scores the stale-dim vector.
+		const data = selectGraphContext({ ...base, vectors, nodes, budget: 4096 });
+		assert.deepEqual(
+			data.propositions.map((p) => p.id),
+			["ok"],
+		);
+	});
+});
+
+describe("graphContextText + hasContext — the canonical block", () => {
+	it("carries the counts in the header, the level tag per line, the gloss at the end", () => {
+		const data: GraphContextData = {
+			chatId: "c1",
+			budget: 1024,
+			tokens: 42,
+			propositions: [
+				{ id: "n1", statement: "Water boils at 100°C.", level: "solid" },
+				{ id: "n2", statement: "Humidity slows evaporation.", level: null },
+			],
+		};
+		const text = graphContextText(data);
+		assert.match(text, /2 propositions, ~42 tokens/);
+		assert.match(text, /- \[solid\] Water boils at 100°C\./);
+		assert.match(text, /- Humidity slows evaporation\./);
+		assert.match(text, /Do not re-teach solid ground\./);
+	});
+
+	it("an empty selection has no text and no context", () => {
+		const empty: GraphContextData = { chatId: "c1", budget: 1024, tokens: 55, propositions: [] };
+		assert.equal(graphContextText(empty), "");
+		assert.equal(hasContext(empty), false);
+	});
+});
+
+describe("graphContextOfMessage — parse-don't-cast at the marker seam", () => {
+	it("round-trips a well-formed part", () => {
+		const msg = marker("data-graph-context", {
+			chatId: "c1",
+			budget: 512,
+			tokens: 60,
+			propositions: [{ id: "n1", statement: "S.", level: "shaky" }],
+		});
+		const data = graphContextOfMessage(msg);
+		assert.equal(data?.chatId, "c1");
+		assert.equal(data?.propositions[0]?.level, "shaky");
+	});
+
+	it("rejects malformed shapes wholesale (bad level, bad budget, non-array)", () => {
+		assert.equal(graphContextOfMessage(marker("data-graph-context", { chatId: "c" })), null);
+		assert.equal(
+			graphContextOfMessage(
+				marker("data-graph-context", {
+					chatId: "c",
+					budget: 512,
+					tokens: 1,
+					propositions: [{ id: "n", statement: "s", level: "kinda" }],
+				}),
+			),
+			null,
+		);
+		assert.equal(
+			graphContextOfMessage(
+				marker("data-graph-context", { chatId: "c", budget: 999999, tokens: 1, propositions: [] }),
+			),
+			null,
+		);
+	});
+
+	it("absent part → null", () => {
+		assert.equal(graphContextOfMessage(userText("hello")), null);
+	});
+});
+
+describe("buildGraphContextSteer — the marker-only delivery", () => {
+	it("id is deterministic per chat; metadata carries chat + job; one part", () => {
+		const data: GraphContextData = {
+			chatId: "chat_9",
+			budget: 1024,
+			tokens: 10,
+			propositions: [{ id: "n1", statement: "S.", level: null }],
+		};
+		const steer = buildGraphContextSteer({ chatId: "chat_9", jobId: "job_1" }, data);
+		assert.equal(steer.id, "steer_ctx_chat_9");
+		assert.equal(steer.role, "user");
+		assert.deepEqual(steer.metadata, { graphContext: { chatId: "chat_9", jobId: "job_1" } });
+		assert.equal(steer.parts.length, 1);
+		assert.equal(steer.parts[0]!.type, "data-graph-context");
+		// steerDelivered keys on the id — the one-shot guard.
+		assert.equal(steerDelivered([steer], "steer_ctx_chat_9"), true);
+	});
+});
+
+describe("the runner's pure gates", () => {
+	it("topicOf: exactly one typed message is the topic; steers and answers never count", () => {
+		assert.equal(topicOf([userText("the water cycle")]), "the water cycle");
+		assert.equal(topicOf([]), null);
+		assert.equal(topicOf([userText("a"), userText("b")]), null);
+		// A quiz answer: tool-output part, no text — probing never breaks the gate.
+		const answer: UIMessage = {
+			id: "m_ans",
+			role: "user",
+			parts: [{ type: "tool-quiz", toolCallId: "t1", state: "output-available", input: {}, output: {} } as never],
+		};
+		assert.equal(topicOf([userText("topic"), answer, marker("data-probe-handoff", { chatId: "c" })]), "topic");
+		// Multi-part text joins into the topic.
+		assert.equal(topicOf([userText("a"), userText("")]), "a");
+	});
+
+	it("effectiveContextBudget: absent = the default (on), 0 = off, set = set", () => {
+		assert.equal(effectiveContextBudget(undefined), GRAPH_CONTEXT_TOKENS_DEFAULT);
+		assert.equal(effectiveContextBudget({}), GRAPH_CONTEXT_TOKENS_DEFAULT);
+		assert.equal(effectiveContextBudget({ graphContextTokens: 0 }), 0);
+		assert.equal(effectiveContextBudget({ graphContextTokens: 2048 }), 2048);
+	});
+
+	it("the decided knobs: default 1024, max 4096, step 128", () => {
+		assert.equal(GRAPH_CONTEXT_TOKENS_DEFAULT, 1024);
+		assert.equal(GRAPH_CONTEXT_TOKENS_MAX, 4096);
+		assert.equal(GRAPH_CONTEXT_TOKENS_STEP, 128);
+	});
+
+	it("contextToolCallId is deterministic per chat (the one-shot dedup key)", () => {
+		assert.equal(contextToolCallId("chat_abc"), "ctx_chat_abc");
+	});
+});
\ No newline at end of file
diff --git a/tests/graph-context-job.test.ts b/tests/graph-context-job.test.ts
new file mode 100644
index 0000000..8cad3ec
--- /dev/null
+++ b/tests/graph-context-job.test.ts
@@ -0,0 +1,316 @@
+/**
+ * Graph context injection — the runner + the wake integration
+ * (docs/vision-context-injection.md). The trigger gates, the failure
+ * modes, the one happy delivery (real wake pipeline, fake turn runner,
+ * scripted embedder), and the SILENT abort (the decided contrast with
+ * teacher-dispatched sub-agents, which abort with a steer).
+ *
+ * Cleanup follows tests/jobs.test.ts: files removed in finally/after.
+ */
+
+import assert from "node:assert/strict";
+import * as fs from "node:fs";
+import * as path from "node:path";
+import { after, describe, it } from "node:test";
+import { deliverJobResult, setTurnRunner } from "../src/server/jobs.ts";
+import { abortJob } from "../src/server/jobs.ts";
+import { persistTurn } from "../src/server/turn-service.ts";
+import { startGraphContextInjection, runGraphContextJob, type GraphContextDeps } from "../src/agent/subagents/graph-context.ts";
+import { chatStore } from "../src/store/chats.ts";
+import { jobStore } from "../src/store/jobs.ts";
+import { PATHS } from "../config.ts";
+import type { EmbeddingsLedger, GraphNode, LedgerEvent } from "../src/core/contracts/graph.ts";
+import type { JobRecord, SteerMessage } from "../src/core/contracts.ts";
+
+const createdChats: string[] = [];
+const createdJobs: string[] = [];
+
+function trackChat(id: string) {
+	createdChats.push(id);
+}
+function trackJob(id: string) {
+	createdJobs.push(id);
+}
+
+after(() => {
+	for (const id of createdChats) {
+		try {
+			fs.unlinkSync(path.join(PATHS.chats, `${id}.json`));
+		} catch {
+			/* already gone */
+		}
+	}
+	for (const id of createdJobs) {
+		try {
+			fs.unlinkSync(path.join(PATHS.data, "jobs", `${id}.json`));
+		} catch {
+			/* already gone */
+		}
+	}
+});
+
+function waitFor(cond: () => boolean, timeoutMs = 8000, what = "condition"): Promise<void> {
+	return new Promise((resolve, reject) => {
+		const started = Date.now();
+		const tick = () => {
+			if (cond()) return resolve();
+			if (Date.now() - started > timeoutMs) return reject(new Error(`timeout waiting for ${what}`));
+			setTimeout(tick, 25);
+		};
+		tick();
+	});
+}
+
+function unit(i: number): number[] {
+	const v = new Array(8).fill(0);
+	v[i] = 1;
+	return v;
+}
+
+function node(id: string, statement: string): GraphNode {
+	return { id, name: id, statement, aliases: [], provenance: [], createdAt: "2026-09-14T00:00:00.000Z" };
+}
+
+/** A minimal in-memory graph store — the runner only reads. */
+function fakeGraphStore(opts: {
+	vectors?: Record<string, number[]>;
+	nodes?: GraphNode[];
+	events?: LedgerEvent[];
+	model?: string;
+	dim?: number;
+}): Pick<GraphContextDeps["graphStore"], "readNodes" | "readEvents" | "readEmbeddings"> {
+	const ledger: EmbeddingsLedger = {
+		model: opts.model ?? "test-embed",
+		dim: opts.dim ?? 8,
+		vectors: opts.vectors ?? {},
+		clusters: [],
+		updatedAt: "2026-09-14T00:00:00.000Z",
+	};
+	return {
+		readNodes: () => opts.nodes ?? [],
+		readEvents: () => opts.events ?? [],
+		readEmbeddings: () => ledger,
+	};
+}
+
+/** A chat at session start: exactly one typed message (the topic). */
+function newTopicChat(label: string, settings?: Record<string, unknown>): { id: string } {
+	const chat = chatStore.createChat(`Test: ${label}`);
+	trackChat(chat.id);
+	chatStore.saveMessages(chat.id, [
+		{ id: "u1", role: "user", parts: [{ type: "text", text: "the water cycle" }] },
+	] as never);
+	if (settings) chatStore.saveSettings(chat.id, settings as never);
+	return { id: chat.id };
+}
+
+/** The scripted embedder: deterministic query vectors, recorded topics. */
+function fakeEmbedder(vec: number[] = unit(0)) {
+	const topics: string[] = [];
+	return {
+		topics,
+		embedder: {
+			model: "test-embed",
+			dim: 8,
+			embedQuery: async (text: string) => {
+				topics.push(text);
+				return vec;
+			},
+		},
+	};
+}
+
+function deps(
+	graph: Pick<GraphContextDeps["graphStore"], "readNodes" | "readEvents" | "readEmbeddings">,
+	embedder: GraphContextDeps["embedder"],
+	deliver: (steer: SteerMessage) => Promise<void>,
+): GraphContextDeps {
+	return { chatStore, jobStore, graphStore: graph, embedder, deliver };
+}
+
+describe("startGraphContextInjection — the one-shot gates", () => {
+	it("starts at session start: job kind graph-context, deterministic toolCallId, runner runs to delivery", async () => {
+		const { id: chatId } = newTopicChat("injection happy gate");
+		const graph = fakeGraphStore({
+			vectors: { n1: unit(0) },
+			nodes: [node("n1", "Water evaporates from oceans.")],
+		});
+		const { embedder, topics } = fakeEmbedder();
+		const delivered: SteerMessage[] = [];
+		const d = deps(graph, embedder, async (steer) => {
+			delivered.push(steer);
+		});
+
+		const job = startGraphContextInjection(d, chatId);
+		assert.ok(job, "a chat at session start with budget on starts the injection");
+		trackJob(job.id);
+		assert.equal(job.kind, "graph-context");
+		assert.equal(job.toolCallId, `ctx_${chatId}`);
+
+		await waitFor(() => delivered.length > 0, 8000, "delivery");
+		assert.deepEqual(topics, ["the water cycle"], "the topic is the session's only typed message");
+		const steer = delivered[0]!;
+		assert.equal(steer.id, `steer_ctx_${chatId}`);
+		assert.equal(steer.parts.length, 1);
+		assert.equal(steer.parts[0]!.type, "data-graph-context");
+
+		// One shot: a second trigger does nothing (job exists).
+		assert.equal(startGraphContextInjection(d, chatId), null);
+	});
+
+	it("budget 0 (off) never starts; a session past its start never injects", async () => {
+		const { id: off } = newTopicChat("injection off", { graphContextTokens: 0 });
+		const { id: rolling } = (() => {
+			const chat = chatStore.createChat("Test: two typed messages");
+			trackChat(chat.id);
+			chatStore.saveMessages(chat.id, [
+				{ id: "u1", role: "user", parts: [{ type: "text", text: "topic" }] },
+				{ id: "u2", role: "user", parts: [{ type: "text", text: "a second message" }] },
+			] as never);
+			return { id: chat.id };
+		})();
+		const graph = fakeGraphStore({ vectors: { n1: unit(0) }, nodes: [node("n1", "S.")] });
+		const d = deps(graph, fakeEmbedder().embedder, async () => {});
+
+		assert.equal(startGraphContextInjection(d, off), null, "0 budget = off");
+		assert.equal(startGraphContextInjection(d, rolling), null, "no retroactive injection");
+		assert.equal(jobStore.listJobs(off).length, 0);
+		assert.equal(jobStore.listJobs(rolling).length, 0);
+		assert.equal(startGraphContextInjection(d, "chat_missing"), null, "unknown chat");
+	});
+
+	it("an ERRORED context job still blocks re-injection (one shot means one shot)", async () => {
+		const { id: chatId } = newTopicChat("injection error one-shot");
+		const graph = fakeGraphStore({ vectors: {} }); // empty ledger → the run errors
+		const d = deps(graph, fakeEmbedder().embedder, async () => {});
+		const job = startGraphContextInjection(d, chatId);
+		assert.ok(job);
+		trackJob(job.id);
+		await waitFor(() => jobStore.getJob(job.id)!.status === "error", 8000, "job errors");
+		assert.match(jobStore.getJob(job.id)!.error ?? "", /no embeddings yet/);
+		// Re-trigger with a now-populated ledger: still nothing.
+		const populated = deps(
+			fakeGraphStore({ vectors: { n1: unit(0) }, nodes: [node("n1", "S.")] }),
+			fakeEmbedder().embedder,
+			async () => {},
+		);
+		assert.equal(startGraphContextInjection(populated, chatId), null);
+	});
+});
+
+describe("runGraphContextJob — failure modes are honest errors, never phantom deliveries", () => {
+	it("a stale ledger (model/dim mismatch) errors with the parity reason", async () => {
+		const { id: chatId } = newTopicChat("injection stale ledger");
+		const chat = chatStore.createChat(`Test: ${chatId}`); // placeholder to satisfy lint-free compile
+		trackChat(chat.id);
+		const job = jobStore.createJob({ kind: "graph-context", chatId, toolCallId: `ctx_${chatId}` });
+		trackJob(job.id);
+		// Ledger stamped with a DIFFERENT model than the embedder.
+		const d = deps(fakeGraphStore({ vectors: { n1: unit(0) }, model: "other-model" }), fakeEmbedder().embedder, async () => {});
+		await runGraphContextJob(d, job.id);
+		const got = jobStore.getJob(job.id)!;
+		assert.equal(got.status, "error");
+		assert.match(got.error ?? "", /stale/);
+	});
+
+	it("nothing fitting the budget errors rather than delivering an empty block", async () => {
+		// Budget below the framing overhead: nothing can fit, ever.
+		const { id: chatId } = newTopicChat("injection empty selection", { graphContextTokens: 10 });
+		const job = jobStore.createJob({ kind: "graph-context", chatId, toolCallId: `ctx_${chatId}` });
+		trackJob(job.id);
+		// Query orthogonal to every vector; budget can hold nothing.
+		const graph = fakeGraphStore({ vectors: { n1: unit(7) }, nodes: [node("n1", "A very long statement indeed.")] });
+		const d = deps(graph, fakeEmbedder(unit(0)).embedder, async () => {});
+		await runGraphContextJob(d, job.id);
+		const got = jobStore.getJob(job.id)!;
+		assert.equal(got.status, "error");
+		assert.match(got.error ?? "", /nothing relevant fit the budget/);
+	});
+});
+
+describe("the injection + the wake pipeline (end to end, fake turn runner)", () => {
+	it("delivers through the wake: the record gains the marker steer, the job flips done, the dock kind rides along", async () => {
+		const { id: chatId } = newTopicChat("injection wake delivery");
+		const graph = fakeGraphStore({
+			vectors: { n1: unit(0), n2: unit(0) },
+			nodes: [node("n1", "Water evaporates from oceans."), node("n2", "Condensation forms clouds.")],
+			events: [
+				{ nodeId: "n1", kind: "observation", chatId: "chat_old", at: "2026-09-10T00:00:00Z", note: "solid" },
+			],
+		});
+		const fired: { chatId: string; last: SteerMessage }[] = [];
+		setTurnRunner(async (cid, messages) => {
+			// Mimic the real wake turn: write-ahead persistence of the incoming
+			// messages (the handler does this), then 200.
+			await persistTurn(chatStore, cid, messages as never, false);
+			fired.push({ chatId: cid, last: messages[messages.length - 1] as SteerMessage });
+			return 200;
+		});
+
+		const d = deps(graph, fakeEmbedder().embedder, deliverJobResult);
+		const job = startGraphContextInjection(d, chatId);
+		assert.ok(job);
+		trackJob(job.id);
+
+		await waitFor(() => (jobStore.getJob(job.id)?.status ?? "running") === "done", 8000, "wake flipped the job");
+		const got = jobStore.getJob(job.id)!;
+		assert.equal(got.status, "done");
+		assert.equal(got.activity, "delivered");
+
+		// The transcript carries the marker steer (audit trail + dedup key).
+		const record = chatStore.getChat(chatId)!;
+		const steerMsg = record.messages.find((m) => m.id === `steer_ctx_${chatId}`);
+		assert.ok(steerMsg, "the steer persisted to the record");
+		const part = steerMsg.parts[0] as { type: string; data: { propositions?: unknown[] } };
+		assert.equal(part.type, "data-graph-context");
+		assert.ok(part.data.propositions!.length >= 1);
+
+		// The server-side turn fired once, with the steer as its last input.
+		assert.equal(fired.length, 1);
+		assert.equal(fired[0]!.chatId, chatId);
+		assert.equal(fired[0]!.last.id, `steer_ctx_${chatId}`);
+	});
+
+	it("aborts SILENTLY: the record flips, the teacher is never told (nothing was promised)", async () => {
+		const { id: chatId } = newTopicChat("injection abort");
+		// A hanging embedder — killed mid-call, like the research abort test.
+		let release: (() => void) | null = null;
+		const hanging = new Promise<void>((resolve) => {
+			release = resolve;
+		});
+		const embedder = {
+			model: "test-embed",
+			dim: 8,
+			embedQuery: () => hanging.then(() => unit(0)),
+		};
+		const fired: number[] = [];
+		setTurnRunner(async () => {
+			fired.push(1);
+			return 200;
+		});
+		const graph = fakeGraphStore({ vectors: { n1: unit(0) }, nodes: [node("n1", "S.")] });
+		const d = deps(graph, embedder, deliverJobResult);
+		const job = startGraphContextInjection(d, chatId);
+		assert.ok(job);
+		trackJob(job.id);
+
+		await waitFor(() => jobStore.getJob(job.id)!.activity === "embedding topic", 8000, "run started");
+		const outcome = abortJob(job.id);
+		assert.ok(outcome.ok);
+		const got = jobStore.getJob(job.id)!;
+		assert.equal(got.status, "error");
+		assert.equal(got.error, "Aborted by learner");
+
+		release!(); // unwind the hanging call; the abort check exits silently
+		await waitFor(() => fired.length >= 0, 50, "settle");
+		await new Promise((r) => setTimeout(r, 150));
+		assert.equal(fired.length, 0, "NO abort steer — the decided contrast with sub-agent jobs");
+		assert.equal(jobStore.getJob(job.id)!.status, "error", "terminal");
+		// And the chat record never gained a context steer.
+		const record = chatStore.getChat(chatId)!;
+		assert.equal(
+			record.messages.some((m) => m.id === `steer_ctx_${chatId}`),
+			false,
+		);
+	});
+});
\ No newline at end of file
diff --git a/tests/record-adapter.test.ts b/tests/record-adapter.test.ts
index 3eed091..e892071 100644
--- a/tests/record-adapter.test.ts
+++ b/tests/record-adapter.test.ts
@@ -85,4 +85,36 @@ describe("record-adapter: system message flattening", () => {
 		]);
 		assert.equal(out.length, 0, "no model face at all — skipped");
 	});
+
+	it("the graph-context steer flattens to the canonical prior-knowledge block", () => {
+		const out = recordToPiMessages([
+			userParts([
+				{
+					type: "data-graph-context",
+					id: "ctx1",
+					data: {
+						chatId: "chat_1",
+						budget: 1024,
+						tokens: 64,
+						propositions: [
+							{ id: "n1", statement: "Water boils at 100°C.", level: "solid" },
+							{ id: "n2", statement: "Evaporation cools things.", level: null },
+						],
+					},
+				},
+			]),
+		]);
+		assert.equal(out.length, 1, "one user message — the marker part is the model face");
+		const got = texts(out);
+		assert.equal(got.length, 1);
+		assert.match(got[0]!, /Prior-knowledge context/);
+		assert.match(got[0]!, /\[solid\] Water boils at 100°C\./);
+	});
+
+	it("a malformed graph-context part has no model face — the message is skipped wholesale", () => {
+		const out = recordToPiMessages([
+			userParts([{ type: "data-graph-context", id: "ctx2", data: { chatId: "chat_1" } }]),
+		]);
+		assert.equal(out.length, 0, "parse-don't-cast: no validated data, no face");
+	});
 });
\ No newline at end of file
diff --git a/tests/render-activity-dock.test.tsx b/tests/render-activity-dock.test.tsx
index e311a1e..2ea77b9 100644
--- a/tests/render-activity-dock.test.tsx
+++ b/tests/render-activity-dock.test.tsx
@@ -152,6 +152,18 @@ describe("activity section render", () => {
 		assert.match(html, /activity-total-cost[^>]*>—</);
 	});
 
+	it("renders a graph-context job as 'Knowledge context' — the dock's fourth kind", () => {
+		const html = renderToStaticMarkup(
+			<ActivitySection
+				feed={{ jobs: [job({ id: "jctx", kind: "graph-context", activity: "selecting propositions", title: "Water cycle" })], extractions: [] }}
+			/>,
+		);
+		assert.match(html, /data-testid="activity-blob-job"/);
+		assert.match(html, /Knowledge context/);
+		assert.match(html, /selecting propositions/);
+		assert.match(html, /data-testid="activity-abort"/, "END kills the injection like any job");
+	});
+
 	it("shows total running cost when jobs are priced", () => {
 		const usage = {
 			model: "z-ai/glm-5.3-flash",
diff --git a/tests/render-new-session.test.tsx b/tests/render-new-session.test.tsx
index a8675cf..736f962 100644
--- a/tests/render-new-session.test.tsx
+++ b/tests/render-new-session.test.tsx
@@ -84,6 +84,41 @@ describe("DraftShell — the sessionless surface", () => {
 		assert.ok(/rounded-2xl[^>]*pointer-events-auto|pointer-events-auto[^>]*rounded-2xl/.test(html));
 	});
 
+	it("renders the knowledge-context slider at the decided default (absent settings = on, 1024)", () => {
+		const html = renderToStaticMarkup(
+			<DraftShell
+				busy={false}
+				text=""
+				onChange={() => {}}
+				onSend={() => {}}
+				settings={undefined}
+				onSettingsSaved={() => {}}
+			/>,
+		);
+		assert.ok(html.includes('data-testid="graph-context-control"'));
+		// The slider's default position: 1024 of 4096, step 128 (decided).
+		assert.ok(html.includes('min="0"') && html.includes('max="4096"') && html.includes('step="128"'));
+		assert.ok(html.includes("1k tokens"), "the readout shows the default budget, not 0 — default is ON");
+		assert.ok(html.includes("Knowledge context"), "the control is labeled");
+		// Absent settings render the default — never 'off'.
+		assert.ok(!html.includes(">off<"));
+	});
+
+	it("an explicit 0 renders as off — the learner turned the graph off for this session", () => {
+		const html = renderToStaticMarkup(
+			<DraftShell
+				busy={false}
+				text=""
+				onChange={() => {}}
+				onSend={() => {}}
+				settings={{ graphContextTokens: 0 }}
+				onSettingsSaved={() => {}}
+			/>,
+		);
+		assert.ok(html.includes('data-testid="graph-context-value"'));
+		assert.ok(html.includes(">off<"));
+	});
+
 	it("no chat id anywhere — nothing in the markup references a session", () => {
 		const html = renderToStaticMarkup(
 			<DraftShell