diff --git a/README.md b/README.md
index 4defd35..49d9060 100644
--- a/README.md
+++ b/README.md
@@ -326,6 +326,9 @@ Cloud viewer journey is still unproven, and the old draft
 evidence for current `main`. The source-candidate contract is:
 
 - Starting a session prints a link and a QR code.
+- `aether --json rc start|link|status` gives local integrations one structured
+  session/device identity. Only `start` and `link` return the short-lived
+  observer link; `status` never replays it. Integrations must not log that link.
 - Your phone or browser **watches** the run. It never gets tool authority.
 - One command shows what is exposed; another revokes it.
 - Outbound TLS only — no inbound listener on your machine.
diff --git a/src/commands/rc.ts b/src/commands/rc.ts
index aba557f..ba87db0 100644
--- a/src/commands/rc.ts
+++ b/src/commands/rc.ts
@@ -34,6 +34,7 @@ import { detectBrowserRuntime } from "../core/browser_runtime.js";
 import { McpClient } from "../core/mcp.js";
 import { loadEnrollmentMetadata } from "../core/device_runtime/identity.js";
 import {
+  RC_HOST_SCHEMA,
   RcError,
   attachHost,
   flushOutbox,
@@ -252,25 +253,49 @@ export interface RcCommandDeps {
   err: (text: string) => void;
   isTTY: boolean;
   columns: number | undefined;
+  json: boolean;
+}
+
+interface RcObserverInvitation {
+  url: string;
+  expires_at: string;
+}
+
+/** Stable machine handoff for a caller that must bind its own browser session. */
+export function renderStatusJson(view: RcStatusView, invitation: RcObserverInvitation | null = null): string {
+  return JSON.stringify({
+    schema: RC_HOST_SCHEMA,
+    host_state: view.running ? view.state : "off",
+    session_id: view.session_id,
+    device_id: view.device_id,
+    project_ref: view.project_ref,
+    revoke_pending: view.revoke_pending,
+    outbox_pending: view.pending,
+    acked_seq: view.acked,
+    viewer_capabilities: VIEWER_CAPABILITIES,
+    observer: invitation,
+  }) + "\n";
 }
 
 async function printObserverLink(
   deps: RcCommandDeps,
   hostDeps: RcHostDeps,
   sessionId: string,
-): Promise<boolean> {
+): Promise<RcObserverInvitation | null> {
   try {
     const grant = await mintObserverGrant(hostDeps, sessionId, newObserverId());
     const link = observerLink(grant);
-    deps.out(`\nObserver link (expires ${grant.expires_at}):\n${link}\n`);
-    const qr = deps.isTTY ? observerQr(link, deps.columns) : null;
-    if (qr) deps.out(`${qr}\n`);
-    else deps.out("Open the link directly; this terminal cannot fit a scannable QR.\n");
-    return true;
+    if (!deps.json) {
+      deps.out(`\nObserver link (expires ${grant.expires_at}):\n${link}\n`);
+      const qr = deps.isTTY ? observerQr(link, deps.columns) : null;
+      if (qr) deps.out(`${qr}\n`);
+      else deps.out("Open the link directly; this terminal cannot fit a scannable QR.\n");
+    }
+    return { url: link, expires_at: grant.expires_at };
   } catch (error) {
     const code = error instanceof RcError ? error.code : "RC_BROKER_UNREACHABLE";
     deps.err(`${code}: RC is running, but an observer link could not be minted. Retry with \`aether rc link\`.\n`);
-    return false;
+    return null;
   }
 }
 
@@ -282,7 +307,7 @@ function viewOf(record: OutboxRecord, deps: RcCommandDeps, observers: number | n
     browser: browser?.code ?? null,
     connector: deps.connector(),
     last_receipt: null,
-    device_id: enrolled?.device_id ?? null,
+    device_id: record.session_id ? record.device_id : enrolled?.device_id ?? null,
     device_name: enrolled?.display_name ?? null,
     session_id: record.session_id || null,
     project_ref: record.project_ref || null,
@@ -358,9 +383,10 @@ async function start(
     saveOutbox(hostDeps.outboxPath, record);
     const flushed = await flushOutbox(hostDeps, record);
 
-    deps.out(renderStatus(viewOf(record, deps, null)));
-    if (flushed.ok) await printObserverLink(deps, hostDeps, session.session_id);
-    else deps.err(`${flushed.code}: RC is running, but its opening events are pending. Retry with \`aether rc link\`.\n`);
+    if (!deps.json) deps.out(renderStatus(viewOf(record, deps, null)));
+    const invitation = flushed.ok ? await printObserverLink(deps, hostDeps, session.session_id) : null;
+    if (!flushed.ok) deps.err(`${flushed.code}: RC is running, but its opening events are pending. Retry with \`aether rc link\`.\n`);
+    if (deps.json) deps.out(renderStatusJson(viewOf(record, deps, null), invitation));
     return EXIT_OK;
   } catch (error) {
     if (error instanceof RcError) {
@@ -396,6 +422,7 @@ export async function cmdRc(
     err: overrides.err ?? ((text): void => void process.stderr.write(text)),
     isTTY: overrides.isTTY ?? Boolean(process.stdout.isTTY),
     columns: overrides.columns ?? process.stdout.columns,
+    json: overrides.json ?? ctx.flags.json,
   };
 
   // Connector state is read once, best-effort, before anything renders. A
@@ -421,7 +448,7 @@ export async function cmdRc(
       return start(deps, hostDeps, record, flags.str("name"), projectRef);
 
     case "status":
-      deps.out(renderStatus(viewOf(record, deps, null)));
+      deps.out(deps.json ? renderStatusJson(viewOf(record, deps, null)) : renderStatus(viewOf(record, deps, null)));
       return EXIT_OK;
 
     case "link":
@@ -435,7 +462,9 @@ export async function cmdRc(
           deps.err(`${flushed.code}: RC opening events are still pending. Retry \`aether rc link\` after reconnecting.\n`);
           return EXIT_OPERATIONAL;
         }
-        return await printObserverLink(deps, hostDeps, record.session_id) ? EXIT_OK : EXIT_OPERATIONAL;
+        const invitation = await printObserverLink(deps, hostDeps, record.session_id);
+        if (deps.json && invitation) deps.out(renderStatusJson(viewOf(record, deps, null), invitation));
+        return invitation ? EXIT_OK : EXIT_OPERATIONAL;
       }
 
     case "exposure":
@@ -460,7 +489,8 @@ export async function cmdRc(
         deps.err(`${outcome.code}: ${outcome.detail}\n`);
         return EXIT_OPERATIONAL;
       }
-      deps.out("RC is off. The session, its grants and its streams are revoked.\n");
+      deps.out(deps.json ? renderStatusJson(viewOf(record, deps, null)) :
+        "RC is off. The session, its grants and its streams are revoked.\n");
       return EXIT_OK;
     }
 
diff --git a/test/rc_command.test.ts b/test/rc_command.test.ts
index 596b7f8..e9bb219 100644
--- a/test/rc_command.test.ts
+++ b/test/rc_command.test.ts
@@ -11,16 +11,24 @@
 
 import { test } from "node:test";
 import assert from "node:assert/strict";
+import { mkdtempSync, rmSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
 
 import {
   RC_NO_CONTROL_LINE,
+  cmdRc,
   renderExposure,
   renderStatus,
+  renderStatusJson,
   type RcStatusView,
 } from "../src/commands/rc.js";
 import { COMMAND_MANIFEST_SOURCE } from "../src/commands/command_manifest_data.js";
 import { assertViewerManifest, tokenize } from "../src/core/rc/viewer_profile.js";
 import { producerCoverage } from "../src/core/rc/producers.js";
+import { payloadDigest } from "../src/core/rc/receipts.js";
+import type { AppContext } from "../src/core/context.js";
+import type { CommandFlags } from "../src/core/command_dispatch.js";
 
 const TOKEN_SHAPED = "aek_" + "Z".repeat(32);
 
@@ -215,6 +223,100 @@ test("status renders with nothing running and invents no session", () => {
   assert.match(text, /session\s+—/);
 });
 
+test("machine status binds session and device without replaying an invitation", () => {
+  const data = JSON.parse(renderStatusJson(view())) as Record<string, unknown>;
+  assert.equal(data["schema"], "aether.cli.rc/1");
+  assert.equal(data["session_id"], "rs_" + "e".repeat(32));
+  assert.equal(data["device_id"], "dev-1");
+  assert.equal(data["host_state"], "active");
+  assert.deepEqual(data["viewer_capabilities"], ["observe"]);
+  assert.equal(data["observer"], null);
+  assert.ok(!renderStatusJson(view()).includes("rsgt_"));
+});
+
+test("machine handoff carries a one-time link only in the requested start or link result", () => {
+  const url = "https://app.aethersystems.net/rc#grant=rsgt_canary";
+  const data = JSON.parse(renderStatusJson(view(), {
+    url,
+    expires_at: "2026-09-07T00:05:00.000Z",
+  })) as { observer: { url: string; expires_at: string } };
+  assert.equal(data.observer.url, url);
+  assert.equal(data.observer.expires_at, "2026-09-07T00:05:00.000Z");
+});
+
+test("json start and status bind one RC host without replaying the one-time link", async () => {
+  const directory = mkdtempSync(join(tmpdir(), "aether-rc-json-"));
+  const priorConfig = process.env["AETHER_CONFIG_DIR"];
+  process.env["AETHER_CONFIG_DIR"] = directory;
+  const output: string[] = [];
+  const sessionId = "rs_" + "1".repeat(32);
+  const grantToken = "rsgt_" + "a".repeat(48);
+  const api = {
+    async postJson(path: string, body: unknown): Promise<unknown> {
+      if (path === "/remote/sessions") return { session_id: sessionId, state: "pending_host" };
+      if (path.endsWith("/host/attach")) return { session_id: sessionId, state: "live" };
+      if (path.endsWith("/host/events")) {
+        const events = (body as { events: Array<{ host_event_id: string; payload: Record<string, unknown> }> }).events;
+        return { session_id: sessionId, receipts: events.map((event, index) => ({
+          host_event_id: event.host_event_id, seq: index + 1, payload_digest: payloadDigest(event.payload),
+        })) };
+      }
+      if (path.endsWith("/grants")) return {
+        session_id: sessionId, purpose: "observe", device_id: (body as { device_id: string }).device_id,
+        token: grantToken, expires_at: new Date(Date.now() + 300_000).toISOString(),
+      };
+      if (path.endsWith("/revoke")) return {};
+      throw new Error(`unexpected route ${path}`);
+    },
+  };
+  const ctx = { api, flags: { cwd: directory, json: true } } as unknown as AppContext;
+  const flags = { str: () => undefined } as unknown as CommandFlags;
+  const overrides = {
+    cwd: directory,
+    enrollment: () => ({ device_id: "dev-1", display_name: "test" }),
+    repo: () => ({ repo: "fixture", branch: "main", base_commit: "0".repeat(40), dirty_file_count: 0 }),
+    connector: () => null,
+    browser: () => null,
+    out: (value: string) => output.push(value),
+    err: (value: string) => { throw new Error(value); },
+    isTTY: false,
+    columns: undefined,
+  };
+  try {
+    assert.equal(await cmdRc(ctx, ["start"], flags, overrides), 0);
+    assert.equal(output.length, 1);
+    const started = JSON.parse(output.pop()!) as { session_id: string; device_id: string; observer: { url: string } };
+    assert.equal(started.session_id, sessionId);
+    assert.equal(started.device_id, "dev-1");
+    assert.equal(new URL(started.observer.url).search, "");
+    assert.ok(started.observer.url.includes(`#grant=${grantToken}`));
+
+    assert.equal(await cmdRc(ctx, ["status"], flags, overrides), 0);
+    assert.equal(output.length, 1);
+    const status = JSON.parse(output[0]!) as { session_id: string; observer: unknown };
+    assert.equal(status.session_id, sessionId);
+    assert.equal(status.observer, null);
+    assert.ok(!output[0]!.includes(grantToken));
+
+    output.length = 0;
+    assert.equal(await cmdRc(ctx, ["link"], flags, overrides), 0);
+    assert.equal(output.length, 1);
+    const linked = JSON.parse(output.pop()!) as { session_id: string; observer: { url: string } };
+    assert.equal(linked.session_id, sessionId);
+    assert.ok(linked.observer.url.includes(grantToken));
+
+    assert.equal(await cmdRc(ctx, ["off"], flags, overrides), 0);
+    assert.equal(output.length, 1);
+    const closed = JSON.parse(output[0]!) as { session_id: string | null; host_state: string };
+    assert.equal(closed.session_id, null);
+    assert.equal(closed.host_state, "off");
+  } finally {
+    if (priorConfig === undefined) delete process.env["AETHER_CONFIG_DIR"];
+    else process.env["AETHER_CONFIG_DIR"] = priorConfig;
+    rmSync(directory, { recursive: true, force: true });
+  }
+});
+
 // ── 3. Nothing rendered can carry a credential ──────────────────────────────
 
 test("no rendered surface exposes a secret-bearing field", () => {