diff --git a/bootstrap.md b/bootstrap.md
index cbe3e0a..ae4c93d 100644
--- a/bootstrap.md
+++ b/bootstrap.md
@@ -28,6 +28,16 @@ You are the **composition engine** for PromptKit. Your job is to:
 ## How to Begin
 
 1. **Read the manifest** at `manifest.yaml` to discover all available components.
+   Immediately after reading it, **announce the PromptKit version** to the
+   user by reading the top-level `version:` field from `manifest.yaml` and
+   emitting a one-line banner such as `PromptKit v<version> loaded.` before
+   any other output. Use the **parsed YAML scalar value** for `version`, trim
+   surrounding whitespace, and do **not** preserve any YAML quoting characters
+   from the source text. If the parsed `version:` value is missing, unreadable,
+   empty, or whitespace-only, say `PromptKit (version unknown) loaded.`
+   instead — do not fabricate a version number or emit `PromptKit v loaded.`
+   Do the same (re-announce the current version) any time you re-read
+   `bootstrap.md` or `manifest.yaml` later in the session.
 2. **Ask the user** what they want to accomplish. Examples:
    - "I need to write a requirements doc for a new authentication system."
    - "I need to investigate a memory leak in our C codebase."
diff --git a/cli/bin/cli.js b/cli/bin/cli.js
index 9e64730..816b07a 100644
--- a/cli/bin/cli.js
+++ b/cli/bin/cli.js
@@ -6,6 +6,7 @@ const { Command } = require("commander");
 const path = require("path");
 const fs = require("fs");
 const { launchInteractive } = require("../lib/launch");
+const { checkForUpdate, formatBanner } = require("../lib/update-check");
 const {
   loadManifest,
   allComponents,
@@ -61,8 +62,23 @@ program
     "--dry-run",
     "Print the spawn command and args without launching the LLM CLI"
   )
-  .action((opts) => {
+  .option(
+    "--no-update-check",
+    "Skip checking the npm registry for a newer PromptKit version"
+  )
+  .action(async (opts) => {
     ensureContent();
+    if (opts.updateCheck !== false) {
+      try {
+        const result = await checkForUpdate(pkg.name, pkg.version);
+        if (result && result.isUpdate) {
+          console.log(formatBanner(pkg.name, pkg.version, result.latest));
+          console.log();
+        }
+      } catch {
+        // Update checks are strictly best-effort; never fail the CLI over them.
+      }
+    }
     launchInteractive(contentDir, opts.cli || null, { dryRun: !!opts.dryRun });
   });
 
diff --git a/cli/lib/update-check.js b/cli/lib/update-check.js
new file mode 100644
index 0000000..e63722e
--- /dev/null
+++ b/cli/lib/update-check.js
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) PromptKit Contributors
+
+// cli/lib/update-check.js — best-effort npm registry update check for the
+// PromptKit CLI. All network and filesystem operations are wrapped so that
+// any failure (timeout, DNS, bad JSON, unwritable cache dir, etc.) is
+// swallowed — an update check must never block or break the CLI.
+
+const fs = require("fs");
+const os = require("os");
+const path = require("path");
+const https = require("https");
+
+const CACHE_TTL_MS = 24 * 60 * 60 * 1000; // 24 hours
+const FETCH_TIMEOUT_MS = 1500;
+const REGISTRY_BASE = "https://registry.npmjs.org";
+
+function cachePath() {
+  return path.join(os.homedir(), ".promptkit", "update-check.json");
+}
+
+function readCache() {
+  try {
+    return JSON.parse(fs.readFileSync(cachePath(), "utf8"));
+  } catch {
+    return null;
+  }
+}
+
+function writeCache(data) {
+  try {
+    const file = cachePath();
+    fs.mkdirSync(path.dirname(file), { recursive: true });
+    fs.writeFileSync(file, JSON.stringify(data));
+  } catch {
+    // Best-effort only; cache failures must never surface.
+  }
+}
+
+// Parse a version string into [major, minor, patch]. Strips an optional
+// leading 'v' and ignores any prerelease/build suffix after the patch number.
+// Returns null for unparseable input.
+function parseVersion(v) {
+  const match = /^v?(\d+)\.(\d+)\.(\d+)/.exec(String(v || ""));
+  if (!match) return null;
+  return [Number(match[1]), Number(match[2]), Number(match[3])];
+}
+
+function isNewer(candidate, current) {
+  const a = parseVersion(candidate);
+  const b = parseVersion(current);
+  if (!a || !b) return false;
+  for (let i = 0; i < 3; i++) {
+    if (a[i] > b[i]) return true;
+    if (a[i] < b[i]) return false;
+  }
+  return false;
+}
+
+function formatBanner(pkgName, current, latest) {
+  const line1 = `Update available: ${current} -> ${latest}`;
+  const line2 = `Run: npm i -g ${pkgName}`;
+  const inner = Math.max(line1.length, line2.length);
+  const bar = "-".repeat(inner + 2);
+  return (
+    `+${bar}+\n` +
+    `| ${line1.padEnd(inner)} |\n` +
+    `| ${line2.padEnd(inner)} |\n` +
+    `+${bar}+`
+  );
+}
+
+function fetchLatest(pkgName) {
+  return new Promise((resolve) => {
+    const url = `${REGISTRY_BASE}/${pkgName}/latest`;
+    let settled = false;
+    const done = (value) => {
+      if (settled) return;
+      settled = true;
+      resolve(value);
+    };
+    try {
+      const req = https.get(
+        url,
+        { timeout: FETCH_TIMEOUT_MS, headers: { Accept: "application/json" } },
+        (res) => {
+          if (res.statusCode !== 200) {
+            res.resume();
+            return done(null);
+          }
+          let body = "";
+          res.setEncoding("utf8");
+          res.on("data", (chunk) => {
+            body += chunk;
+            // Hard cap to avoid unbounded memory on a misbehaving registry.
+            if (body.length > 64 * 1024) {
+              req.destroy();
+              done(null);
+            }
+          });
+          res.on("end", () => {
+            try {
+              const json = JSON.parse(body);
+              done(typeof json.version === "string" ? json.version : null);
+            } catch {
+              done(null);
+            }
+          });
+          res.on("error", () => done(null));
+        }
+      );
+      req.on("timeout", () => {
+        req.destroy();
+        done(null);
+      });
+      req.on("error", () => done(null));
+    } catch {
+      done(null);
+    }
+  });
+}
+
+// Decide whether update checking should be performed in this invocation.
+// Returns a short string describing the suppression reason, or null if the
+// check should proceed.
+function suppressionReason({ force = false, ttyOverride } = {}) {
+  if (force) return null;
+  if (process.env.NO_UPDATE_NOTIFIER === "1") return "NO_UPDATE_NOTIFIER";
+  if (process.env.CI) return "CI";
+  const isTty = ttyOverride !== undefined ? ttyOverride : !!process.stdout.isTTY;
+  if (!isTty) return "non-tty";
+  return null;
+}
+
+async function checkForUpdate(
+  pkgName,
+  currentVersion,
+  { force = false, now = Date.now() } = {}
+) {
+  if (suppressionReason({ force })) return null;
+
+  const cache = readCache();
+  let latest = null;
+
+  if (
+    !force &&
+    cache &&
+    cache.pkg === pkgName &&
+    typeof cache.latest === "string" &&
+    typeof cache.checkedAt === "number" &&
+    now - cache.checkedAt < CACHE_TTL_MS
+  ) {
+    latest = cache.latest;
+  } else {
+    latest = await fetchLatest(pkgName);
+    if (latest) {
+      writeCache({ pkg: pkgName, latest, checkedAt: now });
+    }
+  }
+
+  if (!latest) return null;
+  return { latest, isUpdate: isNewer(latest, currentVersion) };
+}
+
+module.exports = {
+  checkForUpdate,
+  formatBanner,
+  isNewer,
+  parseVersion,
+  suppressionReason,
+  // Exported for tests that need to bypass the real paths.
+  _internals: { cachePath, readCache, writeCache, fetchLatest },
+};
diff --git a/cli/package.json b/cli/package.json
index 0ddfe91..2e54c00 100644
--- a/cli/package.json
+++ b/cli/package.json
@@ -20,7 +20,7 @@
     "prepublishOnly": "node scripts/copy-content.js",
     "prepare": "node scripts/copy-content.js",
     "pretest": "node scripts/copy-content.js",
-    "test": "node --test --test-concurrency=1 tests/cli.test.js tests/list.test.js tests/search-show.test.js tests/launch.test.js tests/copy-content.test.js"
+    "test": "node --test --test-concurrency=1 tests/cli.test.js tests/list.test.js tests/search-show.test.js tests/launch.test.js tests/copy-content.test.js tests/update-check.test.js"
   },
   "dependencies": {
     "commander": "^12.0.0",
diff --git a/cli/tests/cli.test.js b/cli/tests/cli.test.js
index 29003bc..1d29654 100644
--- a/cli/tests/cli.test.js
+++ b/cli/tests/cli.test.js
@@ -71,6 +71,12 @@ function makeTempContent(removeFiles) {
     fs.copyFileSync(manifestJs, path.join(tmpLib, "manifest.js"));
   }
 
+  // Copy lib/update-check.js (required by bin/cli.js)
+  const updateCheckJs = path.resolve(__dirname, "..", "lib", "update-check.js");
+  if (fs.existsSync(updateCheckJs)) {
+    fs.copyFileSync(updateCheckJs, path.join(tmpLib, "update-check.js"));
+  }
+
   // Copy node_modules (symlink for speed)
   const srcModules = path.resolve(__dirname, "..", "node_modules");
   const destModules = path.join(tmpCli, "node_modules");
diff --git a/cli/tests/update-check.test.js b/cli/tests/update-check.test.js
new file mode 100644
index 0000000..b474b83
--- /dev/null
+++ b/cli/tests/update-check.test.js
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) PromptKit Contributors
+
+// cli/tests/update-check.test.js — unit tests for the update-check module.
+// Exercises pure functions (version parsing, comparison, banner formatting)
+// and the suppression-reason logic. Does not hit the network.
+
+const { describe, it } = require("node:test");
+const assert = require("node:assert");
+
+const {
+  parseVersion,
+  isNewer,
+  formatBanner,
+  suppressionReason,
+  checkForUpdate,
+} = require("../lib/update-check");
+
+describe("parseVersion", () => {
+  it("parses plain semver", () => {
+    assert.deepStrictEqual(parseVersion("1.2.3"), [1, 2, 3]);
+  });
+
+  it("strips leading 'v'", () => {
+    assert.deepStrictEqual(parseVersion("v0.6.1"), [0, 6, 1]);
+  });
+
+  it("ignores prerelease and build metadata after patch", () => {
+    assert.deepStrictEqual(parseVersion("1.2.3-rc.1"), [1, 2, 3]);
+    assert.deepStrictEqual(parseVersion("1.2.3+build.5"), [1, 2, 3]);
+  });
+
+  it("returns null for garbage input", () => {
+    assert.strictEqual(parseVersion(""), null);
+    assert.strictEqual(parseVersion("not-a-version"), null);
+    assert.strictEqual(parseVersion(undefined), null);
+    assert.strictEqual(parseVersion(null), null);
+    assert.strictEqual(parseVersion("1.2"), null);
+  });
+});
+
+describe("isNewer", () => {
+  it("detects major, minor, and patch bumps", () => {
+    assert.strictEqual(isNewer("1.0.0", "0.9.9"), true);
+    assert.strictEqual(isNewer("0.7.0", "0.6.9"), true);
+    assert.strictEqual(isNewer("0.6.2", "0.6.1"), true);
+  });
+
+  it("returns false for equal versions", () => {
+    assert.strictEqual(isNewer("0.6.1", "0.6.1"), false);
+  });
+
+  it("returns false when candidate is older", () => {
+    assert.strictEqual(isNewer("0.5.0", "0.6.0"), false);
+    assert.strictEqual(isNewer("0.6.0", "0.6.1"), false);
+    assert.strictEqual(isNewer("0.9.9", "1.0.0"), false);
+  });
+
+  it("returns false on unparseable input", () => {
+    assert.strictEqual(isNewer("bogus", "0.6.1"), false);
+    assert.strictEqual(isNewer("0.6.1", "bogus"), false);
+  });
+});
+
+describe("formatBanner", () => {
+  it("produces a boxed banner containing both versions and the package", () => {
+    const banner = formatBanner("@alan-jowett/promptkit", "0.6.1", "0.7.0");
+    assert.match(banner, /Update available: 0\.6\.1 -> 0\.7\.0/);
+    assert.match(banner, /npm i -g @alan-jowett\/promptkit/);
+    // Four lines: top bar, two content lines, bottom bar.
+    assert.strictEqual(banner.split("\n").length, 4);
+  });
+
+  it("pads content lines to the same width", () => {
+    const banner = formatBanner("pkg", "1.0.0", "2.0.0");
+    const lines = banner.split("\n");
+    assert.strictEqual(lines[0].length, lines[3].length);
+    assert.strictEqual(lines[1].length, lines[2].length);
+    assert.strictEqual(lines[0].length, lines[1].length);
+  });
+});
+
+describe("suppressionReason", () => {
+  function withEnv(overrides, fn) {
+    const saved = {};
+    for (const key of Object.keys(overrides)) {
+      saved[key] = process.env[key];
+      if (overrides[key] === undefined) delete process.env[key];
+      else process.env[key] = overrides[key];
+    }
+    try {
+      return fn();
+    } finally {
+      for (const key of Object.keys(saved)) {
+        if (saved[key] === undefined) delete process.env[key];
+        else process.env[key] = saved[key];
+      }
+    }
+  }
+
+  it("returns 'NO_UPDATE_NOTIFIER' when the env var is '1'", () => {
+    withEnv({ NO_UPDATE_NOTIFIER: "1", CI: undefined }, () => {
+      assert.strictEqual(
+        suppressionReason({ ttyOverride: true }),
+        "NO_UPDATE_NOTIFIER"
+      );
+    });
+  });
+
+  it("returns 'CI' when CI env var is set", () => {
+    withEnv({ NO_UPDATE_NOTIFIER: undefined, CI: "true" }, () => {
+      assert.strictEqual(suppressionReason({ ttyOverride: true }), "CI");
+    });
+  });
+
+  it("returns 'non-tty' when stdout is not a TTY", () => {
+    withEnv({ NO_UPDATE_NOTIFIER: undefined, CI: undefined }, () => {
+      assert.strictEqual(suppressionReason({ ttyOverride: false }), "non-tty");
+    });
+  });
+
+  it("returns null when checks should proceed", () => {
+    withEnv({ NO_UPDATE_NOTIFIER: undefined, CI: undefined }, () => {
+      assert.strictEqual(suppressionReason({ ttyOverride: true }), null);
+    });
+  });
+
+  it("force: true bypasses all suppressions", () => {
+    withEnv({ NO_UPDATE_NOTIFIER: "1", CI: "true" }, () => {
+      assert.strictEqual(
+        suppressionReason({ force: true, ttyOverride: false }),
+        null
+      );
+    });
+  });
+});
+
+describe("checkForUpdate (suppression paths)", () => {
+  it("returns null immediately when suppressed, without network I/O", async () => {
+    const saved = process.env.NO_UPDATE_NOTIFIER;
+    process.env.NO_UPDATE_NOTIFIER = "1";
+    try {
+      const result = await checkForUpdate("@alan-jowett/promptkit", "0.6.1");
+      assert.strictEqual(result, null);
+    } finally {
+      if (saved === undefined) delete process.env.NO_UPDATE_NOTIFIER;
+      else process.env.NO_UPDATE_NOTIFIER = saved;
+    }
+  });
+});