diff --git a/docs/codex-cloud.md b/docs/codex-cloud.md
index 767cd435ad..1e0a3f9fd4 100644
--- a/docs/codex-cloud.md
+++ b/docs/codex-cloud.md
@@ -382,10 +382,13 @@ copying credentials into the checkout.
    but it cannot inject host MCP tools or retroactively grant OAuth. Restart the MCP client or open
    a new task after consent. When the host exposes its app identifiers, pass that non-secret
    inventory to the environment check with
-   `--hosted-app-inventory=github,railway,supabase`. The checker rejects stale `railway_cloud` and
-   unrecognized names (so tokens/secrets are never accepted), reports only allowlisted presence
-   flags in the sanitized capability lines, and leaves the inventory explicitly unverified when the
-   host does not provide it; repository config is never substituted for this evidence.
+   `--hosted-app-inventory=github,railway,supabase`. The exact `=` form is required and the option
+   may appear only once; every other unsupported argument fails closed. The checker rejects stale
+   `railway_cloud`, shared sensitive-token patterns, and identifiers outside its reviewed connector
+   allowlist. It normalizes connector-name case and never echoes supplied values. Invalid input
+   suppresses capability output rather than printing a misleading unverified state. Inventory
+   remains explicitly unverified when the host does not provide it; repository config is never
+   substituted for this evidence.
 4. **Prove the shell boundary before providers.** First run the direct raw-shell command above
    before profiles or command shims. Then run `npm run check:codex-cloud`,
    `npm run check:codex-cloud -- --runtime`, `npm run check:runtime`, and
diff --git a/scripts/check-codex-cloud-setup.mjs b/scripts/check-codex-cloud-setup.mjs
index df3d6362da..5cf8350326 100644
--- a/scripts/check-codex-cloud-setup.mjs
+++ b/scripts/check-codex-cloud-setup.mjs
@@ -11,6 +11,7 @@ import {
   hasSafeGitHubCredentialHelper,
   inspectOriginRemote,
 } from "./ensure-codex-cloud-git-remote.mjs";
+import { redactSensitiveText } from "./sensitive-text.mjs";
 import { providerEnvironmentKeys } from "./test-environment.mjs";
 
 const repoRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
@@ -230,6 +231,8 @@ export const knownHostedAppInventoryNames = Object.freeze([
   "supabase",
   "figma",
   "sentry",
+  "slack",
+  "linear",
   "figma_cloud",
   "sentry_cloud",
   "supabase_cloud",
@@ -255,6 +258,28 @@ export function parseHostedAppInventoryArgument(args) {
     .filter(Boolean);
 }
 
+/**
+ * Reject malformed or ambiguous attempts to supply hosted inventory evidence.
+ * @param {string[]} args
+ * @returns {string[]}
+ */
+export function validateHostedAppInventoryArguments(args) {
+  const exactPrefix = "--hosted-app-inventory=";
+  const exactArguments = args.filter((value) => value.startsWith(exactPrefix));
+  const supportedArguments = new Set(["--environment", "--runtime"]);
+  const unsupportedArguments = args.filter((value) => !supportedArguments.has(value) && !value.startsWith(exactPrefix));
+  const errors = [];
+  if (unsupportedArguments.length > 0) {
+    errors.push(
+      "Unsupported Cloud-check argument; hosted app inventory must use exactly --hosted-app-inventory=<comma-separated-apps>.",
+    );
+  }
+  if (exactArguments.length > 1) {
+    errors.push("Hosted app inventory may be supplied only once.");
+  }
+  return errors;
+}
+
 /**
  * Format hosted-app inventory for sanitized capability output.
  * Never echo arbitrary operator-supplied strings — only allowlisted presence flags.
@@ -263,8 +288,9 @@ export function parseHostedAppInventoryArgument(args) {
  */
 export function hostedAppInventoryCapabilityLine(appNames) {
   if (appNames === null) return "hosted_app.inventory=external-unverified-until-fresh-task";
-  const set = new Set(appNames);
-  const unknownCount = appNames.filter(
+  const normalizedNames = appNames.map((name) => name.toLowerCase());
+  const set = new Set(normalizedNames);
+  const unknownCount = normalizedNames.filter(
     (name) => !knownHostedAppInventoryNames.includes(name) && !staleHostedAppInventoryNames.includes(name),
   ).length;
   const parts = [
@@ -289,11 +315,18 @@ export function validateHostedAppInventory(appNames) {
     errors.push("Hosted app inventory was supplied but contained no app names.");
     return errors;
   }
-  const invalidNames = appNames.filter((name) => !/^[A-Za-z0-9_.-]+$/.test(name));
+  const normalizedNames = appNames.map((name) => name.toLowerCase());
+  const invalidNames = normalizedNames.filter((name) => !/^[A-Za-z0-9_.-]+$/.test(name));
   if (invalidNames.length > 0) {
     errors.push("Hosted app inventory names may contain only letters, numbers, dot, underscore, and hyphen.");
   }
-  const unrecognizedNames = appNames.filter(
+  const credentialShapedNames = appNames.filter((name) => redactSensitiveText(name) !== name || name.length > 128);
+  if (credentialShapedNames.length > 0) {
+    errors.push(
+      "Hosted app inventory appears to contain a credential; supply connector names only, never tokens or secrets.",
+    );
+  }
+  const unrecognizedNames = normalizedNames.filter(
     (name) =>
       /^[A-Za-z0-9_.-]+$/.test(name) &&
       !knownHostedAppInventoryNames.includes(name) &&
@@ -301,10 +334,10 @@ export function validateHostedAppInventory(appNames) {
   );
   if (unrecognizedNames.length > 0) {
     errors.push(
-      `Hosted app inventory contains unrecognized app names; supply only connector names (${knownHostedAppInventoryNames.join(", ")}), never tokens or secrets.`,
+      "Hosted app inventory contains unrecognized connector identifiers; update the checker allowlist before accepting them as evidence.",
     );
   }
-  if (appNames.some((name) => staleHostedAppInventoryNames.includes(name))) {
+  if (normalizedNames.some((name) => staleHostedAppInventoryNames.includes(name))) {
     errors.push(
       "Hosted app inventory contains stale railway_cloud; remove or reconnect that host-local app, then start a fresh task and supply the new inventory.",
     );
@@ -1025,8 +1058,12 @@ export async function validateCodexCloudRuntime(env = process.env) {
 
 if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
   const errors = validateCodexCloudSetup();
-  const hostedAppInventory = parseHostedAppInventoryArgument(process.argv.slice(2));
-  errors.push(...validateHostedAppInventory(hostedAppInventory));
+  const commandArguments = process.argv.slice(2);
+  const hostedAppArgumentErrors = validateHostedAppInventoryArguments(commandArguments);
+  const hostedAppInventory = parseHostedAppInventoryArgument(commandArguments);
+  const hostedAppInventoryErrors = validateHostedAppInventory(hostedAppInventory);
+  const hostedAppInputErrors = [...hostedAppArgumentErrors, ...hostedAppInventoryErrors];
+  errors.push(...hostedAppInputErrors);
   const runtime = process.argv.includes("--runtime");
   const environment = runtime || process.env.CODEX_CLOUD === "1" || process.argv.includes("--environment");
   if (runtime) errors.push(...(await validateCodexCloudRuntime()));
@@ -1040,7 +1077,7 @@ if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.me
       "[Codex Cloud Check] WARN: checkout freshness is unverified during provisioning; run explicit acceptance with CODEX_CLOUD_EXPECTED_BASE_SHA.",
     );
   }
-  if (environment) {
+  if (environment && hostedAppInputErrors.length === 0) {
     console.log("[Codex Cloud Environment] sanitized effective modes and capabilities:");
     for (const line of sanitizedCloudCapabilityLines(process.env, { hostedAppInventory })) console.log(`  ${line}`);
   }
diff --git a/tests/codex-cloud-setup.test.ts b/tests/codex-cloud-setup.test.ts
index b546b3a4ac..39d8b0d636 100644
--- a/tests/codex-cloud-setup.test.ts
+++ b/tests/codex-cloud-setup.test.ts
@@ -25,6 +25,7 @@ import {
   validateCodexCloudEnvironment,
   validateCodexProjectMcpConfiguration,
   validateHostedAppInventory,
+  validateHostedAppInventoryArguments,
   validateMcpConfiguration,
 } from "../scripts/check-codex-cloud-setup.mjs";
 import { providerEnvironmentKeys } from "../scripts/test-environment.mjs";
@@ -446,15 +447,25 @@ describe("Codex Cloud environment contract", () => {
       "Hosted app inventory contains stale railway_cloud; remove or reconnect that host-local app, then start a fresh task and supply the new inventory.",
     );
     expect(validateHostedAppInventory(["github", "railway", "supabase"])).toEqual([]);
-    const secretShaped = "sk-abcdef0123456789tokenvalue";
+    expect(validateHostedAppInventory(["GitHub", "Slack", "Linear"])).toEqual([]);
+    expect(validateHostedAppInventory(["github", "custom-app"])).toContain(
+      "Hosted app inventory contains unrecognized connector identifiers; update the checker allowlist before accepting them as evidence.",
+    );
+    const secretShaped = ["xoxb", "12345678"].join("-");
     expect(validateHostedAppInventory(["github", secretShaped])).toContain(
-      "Hosted app inventory contains unrecognized app names; supply only connector names (github, railway, supabase, figma, sentry, figma_cloud, sentry_cloud, supabase_cloud), never tokens or secrets.",
+      "Hosted app inventory appears to contain a credential; supply connector names only, never tokens or secrets.",
+    );
+    const jwtShaped = [["eyJ", "abcdefgh"].join(""), "ijklmnop", "qrstuvwx"].join(".");
+    expect(validateHostedAppInventory(["github", jwtShaped])).toContain(
+      "Hosted app inventory appears to contain a credential; supply connector names only, never tokens or secrets.",
     );
-    const capabilityLine = hostedAppInventoryCapabilityLine(["github", "railway", "supabase"]);
-    expect(capabilityLine).toContain("hosted_app.inventory=provided count=3");
+    const capabilityLine = hostedAppInventoryCapabilityLine(["GitHub", "railway", "supabase", "Slack", "Linear"]);
+    expect(capabilityLine).toContain("hosted_app.inventory=provided count=5");
     expect(capabilityLine).toContain("github=true");
     expect(capabilityLine).toContain("railway=true");
     expect(capabilityLine).toContain("supabase=true");
+    expect(capabilityLine).toContain("slack=true");
+    expect(capabilityLine).toContain("linear=true");
     expect(capabilityLine).toContain("stale_railway_cloud=false");
     expect(capabilityLine).toContain("unknown=0");
     const leaked = hostedAppInventoryCapabilityLine(["github", secretShaped]);
@@ -463,6 +474,29 @@ describe("Codex Cloud environment contract", () => {
     expect(
       sanitizedCloudCapabilityLines({}, { hostedAppInventory: ["github", secretShaped] }).join("\n"),
     ).not.toContain(secretShaped);
+    expect(validateHostedAppInventoryArguments(["--hosted-app-inventory", "github,railway"])).toContain(
+      "Unsupported Cloud-check argument; hosted app inventory must use exactly --hosted-app-inventory=<comma-separated-apps>.",
+    );
+    expect(validateHostedAppInventoryArguments(["--hosted-app-inventroy=github,railway"])).toContain(
+      "Unsupported Cloud-check argument; hosted app inventory must use exactly --hosted-app-inventory=<comma-separated-apps>.",
+    );
+    expect(
+      validateHostedAppInventoryArguments(["--hosted-app-inventory=github", "--hosted-app-inventory=railway"]),
+    ).toContain("Hosted app inventory may be supplied only once.");
+    expect(validateHostedAppInventoryArguments(["--environment", "--runtime"])).toEqual([]);
+
+    const malformedCli = spawnSync(
+      process.execPath,
+      [
+        fileURLToPath(new URL("../scripts/check-codex-cloud-setup.mjs", import.meta.url)),
+        "--environment",
+        "--hosted-app-inventroy=github",
+      ],
+      { cwd: repoRoot, encoding: "utf8", env: { PATH: process.env.PATH, NODE_ENV: "test" } },
+    );
+    expect(malformedCli.status).toBe(1);
+    expect(malformedCli.stderr).toContain("Unsupported Cloud-check argument");
+    expect(malformedCli.stdout).not.toContain("hosted_app.inventory=");
   });
 
   it("probes the raw task environment without printing credential values", () => {