diff --git a/apps/hub/src/live-app/host-report.ts b/apps/hub/src/live-app/host-report.ts
new file mode 100644
index 00000000..9295c3d5
--- /dev/null
+++ b/apps/hub/src/live-app/host-report.ts
@@ -0,0 +1,10 @@
+import { type } from "arktype";
+
+export const HostReport = type({
+  state: "'starting'",
+  phase: "'installing' | 'starting'",
+  log: "string[]",
+})
+  .or({ state: "'running'", url: "string" })
+  .or({ state: "'failed'", error: "string", log: "string[]" });
+export type HostReport = typeof HostReport.infer;
diff --git a/apps/hub/src/live-app/host.ts b/apps/hub/src/live-app/host.ts
index 6eea154a..3626a00f 100644
--- a/apps/hub/src/live-app/host.ts
+++ b/apps/hub/src/live-app/host.ts
@@ -12,6 +12,7 @@ import { type } from "arktype";
 import { hasCode } from "@intx/types";
 import { liveAppWording } from "../config/live-app.ts";
 import { errorCode } from "../request-error.ts";
+import type { HostReport } from "./host-report.ts";
 import { parseJson } from "../lib/json.ts";
 import { writeBundle } from "../artifacts/design-tools.ts";
 import { bundleFiles, collectApp } from "../builds/app-snapshot.ts";
@@ -21,10 +22,6 @@ import {
   IGNORED_CHANGES,
 } from "../builds/posix-sandbox.ts";
 
-export type HostReport =
-  | { state: "starting"; phase: "installing" | "starting"; log: string[] }
-  | { state: "running"; url: string }
-  | { state: "failed"; error: string; log: string[] };
 export const HostSource = type({ dir: "string > 0" }).or({
   files: { "[string]": "string" },
   "binary?": { "[string]": "string" },
diff --git a/apps/hub/src/live-app/runner.ts b/apps/hub/src/live-app/runner.ts
index 78d89f8e..c2727843 100644
--- a/apps/hub/src/live-app/runner.ts
+++ b/apps/hub/src/live-app/runner.ts
@@ -4,7 +4,8 @@ import { fileURLToPath } from "node:url";
 import { getLogger } from "@intx/log";
 import { errorCode, requestErrorMetadata } from "../request-error.ts";
 import { liveAppWording } from "../config/live-app.ts";
-import type { HostReport, HostSource } from "./host.ts";
+import type { HostSource } from "./host.ts";
+import { HostReport } from "./host-report.ts";
 import type { createLiveAppProxy } from "./proxy.ts";
 
 const log = getLogger(["corbits-builder", "hub", "live-app"]);
@@ -66,7 +67,7 @@ export function createLiveAppRunner(options: {
           end !== -1;
           end = pending.indexOf("\n")
         ) {
-          run.state = JSON.parse(pending.slice(0, end)) as HostReport;
+          run.state = HostReport.assert(JSON.parse(pending.slice(0, end)));
           pending = pending.slice(end + 1);
         }
       }
diff --git a/apps/hub/src/sidecar/manifest-store.ts b/apps/hub/src/sidecar/manifest-store.ts
index 20b52b6e..1e82de18 100644
--- a/apps/hub/src/sidecar/manifest-store.ts
+++ b/apps/hub/src/sidecar/manifest-store.ts
@@ -5,13 +5,14 @@ import { type } from "arktype";
 import { errorText } from "./error-text.ts";
 import { hasCode, type CredentialCipher } from "@intx/types";
 
+const LocalSidecarManifestSchema = type({
+  sidecarId: "string",
+  hubWebSocketUrl: "string",
+  dataDir: "string",
+  token: "string",
+});
 /** The hub's one local sidecar: the identity it authenticates with and where it keeps its state. */
-export type LocalSidecarManifest = {
-  readonly sidecarId: string;
-  readonly hubWebSocketUrl: string;
-  readonly dataDir: string;
-  readonly token: string;
-};
+export type LocalSidecarManifest = typeof LocalSidecarManifestSchema.infer;
 
 /** An allocation the sidecar hosts, at the generation and under the identity the hub offered for it. */
 const LocalSidecarHold = type({
@@ -106,7 +107,7 @@ export function createLocalSidecarManifestStore({
     const text = await readOptional(manifestFile);
     if (text === null) return null;
     try {
-      const stored = JSON.parse(text) as LocalSidecarManifest;
+      const stored = LocalSidecarManifestSchema.assert(JSON.parse(text));
       return {
         ...stored,
         token: await cipher.decrypt(