diff --git a/packages/ts-types/src/schemas/app.ts b/packages/ts-types/src/schemas/app.ts
new file mode 100644
index 0000000..edf3a7b
--- /dev/null
+++ b/packages/ts-types/src/schemas/app.ts
@@ -0,0 +1,98 @@
+import { Type, type Static, type TSchema } from "@sinclair/typebox";
+
+/** Present but possibly null - a column that exists and has no value yet. */
+const Nullable = <T extends TSchema>(schema: T) => Type.Union([schema, Type.Null()]);
+
+/**
+ * What continuum-backend pushes down `/ws/telemetry` to an operator console,
+ * mirroring `schemas/continuum/v1/app/telemetry_message.schema.json` by hand
+ * - the JSON Schema is canonical, change it first.
+ *
+ * ## Why this is camelCase when everything else here is snake_case
+ *
+ * Because this one is not shared with the Rust gateway. `continuum/v1/edge/`
+ * is snake_case so serde derives those names directly; this is the backend's
+ * own HTTP vocabulary, and the browser already consumes camelCase from
+ * `GET /printers`. Giving it a second model of a printer to reconcile would
+ * be the cost of a consistency nobody benefits from.
+ *
+ * This file exists because a previous frontend invented a shape against
+ * nothing - `printerId`, `nozzleTempC`, `progressPct`, `updatedAt` and a
+ * closed `idle|printing|paused|error|offline` enum, inside an envelope no
+ * backend ever sent. Both ends now mirror something.
+ */
+
+/**
+ * A printer as the console displays it: the same shape `GET /printers/:id`
+ * returns, so a client can apply a push to the row it already holds.
+ *
+ * Every telemetry field is nullable, and that is not laziness - a printer
+ * that has never reported has no temperature, and "no data yet" is a
+ * different thing from 0 degrees. A client that renders `?? 0` here will
+ * show a cold printer as a real reading.
+ */
+export const AppPrinterStateSchema = Type.Object({
+  id: Type.String({ format: "uuid" }),
+  farmId: Type.String({ format: "uuid" }),
+  name: Type.String(),
+  vendor: Type.String(),
+  status: Type.Optional(Nullable(Type.String())),
+  /**
+   * The printer's own word for what it is doing - a Bambu's `RUNNING`,
+   * `PREPARE`, `FINISH`. Deliberately not an enum: an unrecognised state
+   * must reach the screen as itself rather than being dropped on the way.
+   */
+  vendorState: Type.Optional(Nullable(Type.String())),
+  vendorErrorCode: Type.Optional(Nullable(Type.Integer())),
+  nozzleTempC: Type.Optional(Nullable(Type.Number())),
+  nozzleTargetTempC: Type.Optional(Nullable(Type.Number())),
+  bedTempC: Type.Optional(Nullable(Type.Number())),
+  bedTargetTempC: Type.Optional(Nullable(Type.Number())),
+  progressPercent: Type.Optional(Nullable(Type.Integer())),
+  currentLayer: Type.Optional(Nullable(Type.Integer())),
+  totalLayers: Type.Optional(Nullable(Type.Integer())),
+  remainingMinutes: Type.Optional(Nullable(Type.Integer())),
+  currentJobName: Type.Optional(Nullable(Type.String())),
+  /** A count of active HMS entries, not messages - we lack Bambu's tables. */
+  activeAlerts: Type.Optional(Nullable(Type.Integer())),
+  /**
+   * The go2rtc stream name, when this printer has a camera that can actually
+   * be restreamed. Null is the common case: only Bambu's X1/H2 class
+   * publishes an RTSP URL. Present means `GET /printers/:id/stream` is worth
+   * calling; null means render no player at all.
+   */
+  cameraStream: Type.Optional(Nullable(Type.String())),
+  /**
+   * When a gateway last reported this printer; null means never. This is how
+   * a client tells "idle" from "nobody has heard from it in an hour", which
+   * the status on its own cannot say.
+   */
+  lastSeenAt: Type.Optional(Nullable(Type.String())),
+});
+export type AppPrinterState = Static<typeof AppPrinterStateSchema>;
+
+export const AppTelemetryMessageSchema = Type.Union([
+  Type.Object(
+    {
+      type: Type.Literal("printer.telemetry"),
+      printer: AppPrinterStateSchema,
+    },
+    { additionalProperties: false },
+  ),
+  /**
+   * Sent once, right after the socket authenticates.
+   *
+   * Worth a message of its own rather than letting the client infer
+   * readiness from silence: an operator with no printers claimed and an
+   * operator whose gateway is offline both see nothing arrive, and those two
+   * need different things said to them.
+   */
+  Type.Object(
+    {
+      type: Type.Literal("ready"),
+      visiblePrinters: Type.Integer({ minimum: 0 }),
+    },
+    { additionalProperties: false },
+  ),
+]);
+export type AppTelemetryMessage = Static<typeof AppTelemetryMessageSchema>;
diff --git a/packages/ts-types/src/schemas/index.ts b/packages/ts-types/src/schemas/index.ts
index 481c3ff..f8f155e 100644
--- a/packages/ts-types/src/schemas/index.ts
+++ b/packages/ts-types/src/schemas/index.ts
@@ -14,3 +14,8 @@ export * from "./edge";
 // stream:camera_frames work queue and the channel:print_alerts notification
 // channel. Mirrors schemas/continuum/v1/ai/.
 export * from "./ai";
+
+// The continuum-backend -> operator console push protocol: /ws/telemetry.
+// Mirrors schemas/continuum/v1/app/. camelCase, unlike the rest - see the
+// file for why.
+export * from "./app";
diff --git a/schemas/continuum/v1/app/telemetry_message.schema.json b/schemas/continuum/v1/app/telemetry_message.schema.json
new file mode 100644
index 0000000..758edbc
--- /dev/null
+++ b/schemas/continuum/v1/app/telemetry_message.schema.json
@@ -0,0 +1,74 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://git.octoturge.com/Continuum/continuum-schemas/raw/branch/main/schemas/continuum/v1/app/telemetry_message.schema.json",
+  "title": "AppTelemetryMessage",
+  "description": "What continuum-backend pushes down /ws/telemetry to an operator console. Discriminated on 'type'. NOTE the casing: camelCase, unlike continuum/v1/edge/ and every other schema here, because this is the backend's own HTTP vocabulary rather than a format shared with the Rust gateway - the browser already consumes camelCase from GET /printers and should not have to hold two models of a printer. A previous frontend invented its own shape against nothing (printerId, nozzleTempC, progressPct, a closed state enum) and no backend ever sent it; this file exists so both ends have something to mirror.",
+  "oneOf": [
+    {
+      "type": "object",
+      "title": "PrinterTelemetryPush",
+      "description": "One printer's current state, sent whenever its gateway reports a change. The payload is deliberately the same shape GET /printers/:id returns, so a client can apply it to the row it already has rather than reconciling two vocabularies. Only printers in an organisation the authenticated user belongs to are ever sent.",
+      "properties": {
+        "type": { "const": "printer.telemetry" },
+        "printer": { "$ref": "#/$defs/PrinterState" }
+      },
+      "required": ["type", "printer"],
+      "additionalProperties": false
+    },
+    {
+      "type": "object",
+      "title": "Ready",
+      "description": "Sent once, immediately after the socket authenticates, naming how many printers the user can see. Worth its own message rather than leaving the client to infer readiness from silence: an operator with no printers claimed and an operator whose gateway is offline both see nothing arrive, and those need different things said to them.",
+      "properties": {
+        "type": { "const": "ready" },
+        "visiblePrinters": { "type": "integer", "minimum": 0 }
+      },
+      "required": ["type", "visiblePrinters"],
+      "additionalProperties": false
+    }
+  ],
+  "$defs": {
+    "PrinterState": {
+      "type": "object",
+      "description": "A printer as the console displays it. Every telemetry field is nullable because a printer that has never reported has no temperature, and 'no data yet' is not 0 degrees.",
+      "properties": {
+        "id": { "type": "string", "format": "uuid" },
+        "farmId": { "type": "string", "format": "uuid" },
+        "name": { "type": "string" },
+        "vendor": { "type": "string" },
+        "status": {
+          "type": ["string", "null"],
+          "description": "The backend's own narrowed status, which the UI filters and groups on."
+        },
+        "vendorState": {
+          "type": ["string", "null"],
+          "description": "The printer's own word for what it is doing - a Bambu's 'RUNNING', 'PREPARE', 'FINISH'. Kept alongside 'status' rather than replaced by it, because the narrowed enum necessarily loses detail an operator sometimes needs. Not an enum here on purpose: an unrecognised state must reach the screen as itself rather than being dropped."
+        },
+        "vendorErrorCode": { "type": ["integer", "null"] },
+        "nozzleTempC": { "type": ["number", "null"] },
+        "nozzleTargetTempC": { "type": ["number", "null"] },
+        "bedTempC": { "type": ["number", "null"] },
+        "bedTargetTempC": { "type": ["number", "null"] },
+        "progressPercent": { "type": ["integer", "null"] },
+        "currentLayer": { "type": ["integer", "null"] },
+        "totalLayers": { "type": ["integer", "null"] },
+        "remainingMinutes": { "type": ["integer", "null"] },
+        "currentJobName": { "type": ["string", "null"] },
+        "activeAlerts": {
+          "type": ["integer", "null"],
+          "description": "How many Health-Management-System entries the printer currently has active. A count, not messages: decoding them needs Bambu's HMS tables, which Continuum does not have."
+        },
+        "cameraStream": {
+          "type": ["string", "null"],
+          "description": "The go2rtc stream name, when this printer has a camera that can actually be restreamed. Null is the common case - only Bambu's X1/H2 class publishes an RTSP URL. Present means it is worth calling GET /printers/:id/stream; null means render no player."
+        },
+        "lastSeenAt": {
+          "type": ["string", "null"],
+          "format": "date-time",
+          "description": "When a gateway last reported this printer. Null means never. This is how a client tells 'idle' from 'nobody has heard from it in an hour', which the status alone cannot say."
+        }
+      },
+      "required": ["id", "farmId", "name", "vendor"]
+    }
+  }
+}