diff --git a/packages/cli/src/commands/githubAppCommands.test.ts b/packages/cli/src/commands/githubAppCommands.test.ts
new file mode 100644
index 000000000..00ce05331
--- /dev/null
+++ b/packages/cli/src/commands/githubAppCommands.test.ts
@@ -0,0 +1,296 @@
+/**
+ * Tests for the `propr github-app manifest` generator. Run with:
+ * `npx tsx --test src/commands/githubAppCommands.test.ts` (from packages/cli).
+ *
+ * Locks in the acceptance criteria from the issue: the right files are written,
+ * the manifest carries the expected webhook URL / permissions / events, the
+ * `.env` snippet selects direct webhook mode with the same secret, and a
+ * repeated run refuses to overwrite unless `--force` is passed.
+ */
+
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import { mkdtemp, rm, readFile, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import {
+  generateGithubAppManifest,
+  generateWebhookSecret,
+  redactSecret,
+  PROPR_APP_PERMISSIONS,
+  PROPR_WEBHOOK_EVENTS,
+  MANIFEST_FILENAME,
+  ENV_FILENAME,
+} from "./githubAppCommands.js";
+
+async function withTempDir(
+  fn: (dir: string) => Promise<void>
+): Promise<void> {
+  const dir = await mkdtemp(path.join(tmpdir(), "propr-ghapp-"));
+  try {
+    await fn(dir);
+  } finally {
+    await rm(dir, { recursive: true, force: true });
+  }
+}
+
+test("writes the manifest and env files into --root", async () => {
+  await withTempDir(async (dir) => {
+    const result = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+    });
+
+    assert.equal(result.manifestPath, path.join(dir, MANIFEST_FILENAME));
+    assert.equal(result.envPath, path.join(dir, ENV_FILENAME));
+
+    // Both files are actually on disk and parseable.
+    const manifestRaw = await readFile(result.manifestPath, "utf-8");
+    const manifest = JSON.parse(manifestRaw);
+    assert.equal(manifest.name, "ProPR");
+
+    const env = await readFile(result.envPath, "utf-8");
+    assert.match(env, /GH_AUTH_MODE=app/);
+  });
+});
+
+test("manifest carries the expected webhook URL, permissions, and events", async () => {
+  await withTempDir(async (dir) => {
+    const { manifest, webhookUrl } = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com/",
+    });
+
+    // Trailing slash on the public URL must not double up in the webhook URL.
+    assert.equal(webhookUrl, "https://propr.example.com/webhook");
+    assert.equal(manifest.hook_attributes.url, webhookUrl);
+    assert.equal(manifest.hook_attributes.active, true);
+    assert.equal(manifest.public, false);
+    assert.equal(manifest.url, "https://propr.example.com");
+
+    assert.deepEqual(manifest.default_permissions, {
+      contents: "write",
+      issues: "write",
+      pull_requests: "write",
+      metadata: "read",
+      actions: "read",
+      checks: "read",
+      statuses: "read",
+    });
+
+    // Every event ProPR's core webhook handler understands must be subscribed.
+    for (const event of [
+      "issues",
+      "issue_comment",
+      "pull_request_review_comment",
+      "pull_request",
+      "check_run",
+      "push",
+      "status",
+    ]) {
+      assert.ok(
+        manifest.default_events.includes(event),
+        `manifest should subscribe to "${event}"`
+      );
+    }
+  });
+});
+
+test("env snippet selects direct webhook mode with the manifest's secret", async () => {
+  await withTempDir(async (dir) => {
+    const result = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+    });
+
+    const env = await readFile(result.envPath, "utf-8");
+    assert.match(env, /^GH_AUTH_MODE=app$/m);
+    assert.match(env, /^GITHUB_EVENT_INTAKE_MODE=direct_webhook$/m);
+    assert.match(
+      env,
+      new RegExp(`^GH_WEBHOOK_SECRET=${result.webhookSecret}$`, "m")
+    );
+
+    // The secret in the env file and the manifest must be identical.
+    assert.equal(result.manifest.hook_attributes.secret, result.webhookSecret);
+  });
+});
+
+test("generates a cryptographically strong secret when none is supplied", async () => {
+  await withTempDir(async (dir) => {
+    const { webhookSecret } = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+    });
+    // 32 random bytes -> 64 hex chars.
+    assert.match(webhookSecret, /^[0-9a-f]{64}$/);
+  });
+});
+
+test("honors a supplied webhook secret", async () => {
+  await withTempDir(async (dir) => {
+    const { webhookSecret, manifest } = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+      webhookSecret: "my-explicit-secret",
+    });
+    assert.equal(webhookSecret, "my-explicit-secret");
+    assert.equal(manifest.hook_attributes.secret, "my-explicit-secret");
+  });
+});
+
+test("refuses to overwrite existing files without force", async () => {
+  await withTempDir(async (dir) => {
+    await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+    });
+
+    await assert.rejects(
+      generateGithubAppManifest({
+        root: dir,
+        publicUrl: "https://propr.example.com",
+      }),
+      /Refusing to overwrite/
+    );
+  });
+});
+
+test("refuses even when only one of the two output files exists", async () => {
+  await withTempDir(async (dir) => {
+    // Pre-create just the env file; the manifest does not exist yet. The
+    // preflight must still refuse so we never write a half-pair.
+    await writeFile(path.join(dir, ENV_FILENAME), "stale\n", "utf-8");
+
+    await assert.rejects(
+      generateGithubAppManifest({
+        root: dir,
+        publicUrl: "https://propr.example.com",
+      }),
+      /Refusing to overwrite/
+    );
+
+    // The manifest must not have been written by the refused run.
+    await assert.rejects(readFile(path.join(dir, MANIFEST_FILENAME), "utf-8"));
+  });
+});
+
+test("force overwrites existing files", async () => {
+  await withTempDir(async (dir) => {
+    const first = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+    });
+    const second = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+      force: true,
+    });
+    // A fresh secret each run confirms the second write actually replaced the
+    // first rather than being skipped.
+    assert.notEqual(first.webhookSecret, second.webhookSecret);
+  });
+});
+
+test("rejects a non-http(s) public URL", async () => {
+  await withTempDir(async (dir) => {
+    await assert.rejects(
+      generateGithubAppManifest({ root: dir, publicUrl: "ftp://nope.example" }),
+      /must use http:\/\/ or https:\/\//
+    );
+    await assert.rejects(
+      generateGithubAppManifest({ root: dir, publicUrl: "not a url" }),
+      /is not a valid URL/
+    );
+  });
+});
+
+test("requires a public URL", async () => {
+  await withTempDir(async (dir) => {
+    await assert.rejects(
+      generateGithubAppManifest({ root: dir, publicUrl: "  " }),
+      /public base URL is required/
+    );
+  });
+});
+
+test("a custom webhook URL overrides the default", async () => {
+  await withTempDir(async (dir) => {
+    const { webhookUrl, manifest } = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+      webhookUrl: "https://hooks.example.com/ingest",
+    });
+    assert.equal(webhookUrl, "https://hooks.example.com/ingest");
+    assert.equal(manifest.hook_attributes.url, "https://hooks.example.com/ingest");
+  });
+});
+
+test("org scoping points the create URL at the org App page", async () => {
+  await withTempDir(async (dir) => {
+    const personal = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+    });
+    assert.equal(personal.createUrl, "https://github.com/settings/apps/new");
+
+    const org = await generateGithubAppManifest({
+      root: dir,
+      publicUrl: "https://propr.example.com",
+      org: "acme",
+      force: true,
+    });
+    assert.equal(
+      org.createUrl,
+      "https://github.com/organizations/acme/settings/apps/new"
+    );
+  });
+});
+
+test("redactSecret hides the secret in both places without mutating the input", () => {
+  const secret = generateWebhookSecret();
+  const result = {
+    directory: "/tmp/x",
+    manifestPath: "/tmp/x/m.json",
+    envPath: "/tmp/x/e.env",
+    publicUrl: "https://propr.example.com",
+    webhookUrl: "https://propr.example.com/webhook",
+    webhookSecret: secret,
+    createUrl: "https://github.com/settings/apps/new",
+    manifest: {
+      name: "ProPR",
+      url: "https://propr.example.com",
+      hook_attributes: {
+        url: "https://propr.example.com/webhook",
+        active: true,
+        secret,
+      },
+      redirect_url: "https://propr.example.com/",
+      public: false,
+      default_permissions: { ...PROPR_APP_PERMISSIONS },
+      default_events: [...PROPR_WEBHOOK_EVENTS],
+    },
+  };
+
+  const redacted = redactSecret(result);
+  assert.notEqual(redacted.webhookSecret, secret);
+  assert.notEqual(redacted.manifest.hook_attributes.secret, secret);
+  // Original is untouched.
+  assert.equal(result.webhookSecret, secret);
+  assert.equal(result.manifest.hook_attributes.secret, secret);
+});
+
+test("CLI events list matches the documented core webhook events", () => {
+  // Guards against drift: PROPR_WEBHOOK_EVENTS in the CLI must mirror
+  // SUPPORTED_WEBHOOK_EVENTS in @propr/core (duplicated intentionally to avoid
+  // a core dependency).
+  assert.deepEqual(PROPR_WEBHOOK_EVENTS, [
+    "issues",
+    "issue_comment",
+    "pull_request_review_comment",
+    "pull_request",
+    "check_run",
+    "push",
+    "status",
+  ]);
+});