lulu-ads

The monetization layer for the agent economy.

Monetize your MCP server or agent tool with one labeled sponsored line.

Quickstart · Integrations · Supported hosts · Supported surfaces · stdio servers · Guarantees · API contract · Hosted docs · Blog · Become a publisher

70% to publishers · CPA only · 800ms fail-open · 0 prompt injections, by design

_{↑ live rendered sponsor card — real rotating ad demand, refreshes every ~60s. Any claimed listing can embed this in its own README.}

Lulu Ads attaches a disclosed, labeled data field to your tool's own result. The host model — Claude, Cursor, any agent — decides on its own judgment whether it's relevant enough to surface. We never instruct it to.

{
  "sponsored": {
    "label": "Sponsored",
    "text": "Direct flights TLV–BKK from $412",
    "url": "https://ads.getlulu.dev/c/9f2a1c"
  }
}

Zero-friction start — add the MCP server and let your agent do the rest:

claude mcp add --transport http lulu-ads https://ads.getlulu.dev/mcp

monetize my server

It'll fetch the right integration guide for your stack, register a publisher (with your consent), wire up the one-liner, and verify a slot went live.

If it renders and gets clicked, you earn 70% on CPA. If it doesn't — nobody pays, nothing breaks.

No prompt injection — we ship a data field; the host decides.

Quickstart

Python

pip install lulu-ads
# or: uv add lulu-ads
# or: poetry add lulu-ads

from lulu_ads import LuluAds
ads = LuluAds(publisher_id="pub_123", api_key="lk_...")

result = search_flights("TLV", "BKK", dates)
result["sponsored"] = await ads.sponsored_slot(
    context={"tool": "search_flights", "category": "travel.flights"},
)
return result

FastMCP servers get it in one call — credentials come from the environment, and every tool (present and future) gets both the plain sponsored data field AND, in hosts that support it (e.g. Claude.ai), the rendered Sponsored-card widget, automatically:

export LULU_ADS_PUBLISHER_ID=pub_123
export LULU_ADS_API_KEY=lk_...

from lulu_ads.enable import enable_lulu_ads

enable_lulu_ads(mcp, endpoint_url="https://my-server.example.com/mcp")

Just want the data field, no widget? The plain middleware still works on its own:

mcp.add_middleware(LuluAdsMiddleware())

TypeScript

npm install lulu-ads
# or: pnpm add lulu-ads
# or: yarn add lulu-ads
# or: bun add lulu-ads

import { LuluAds } from "lulu-ads";
const ads = new LuluAds({ publisherId: "pub_123", apiKey: "lk_..." });
result.sponsored = await ads.sponsoredSlot({ context: { tool: "search_flights" } });

MCP servers built on the official TS SDK get the same one-call treatment — data field AND widget on every tool, automatically:

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { enableLuluAds } from "lulu-ads/mcp";

const server = new McpServer({ name: "my-server", version: "1.0.0" });
await enableLuluAds(server, { endpointUrl: "https://my-server.example.com/mcp" });

No publisher ID yet? See docs/quickstart.md — three ways to get one, none of them gated on the others.

Tiered pricing (ads on a free tier, ad-free on paid)? Pass enabled — your own subscription check decides the value, no separate deployment or scattered conditionals needed:

result["sponsored"] = await ads.sponsored_slot(
    context={"tool": "search_flights"},
    enabled=user.tier != "paid",  # False resolves instantly, no network call
)

result.sponsored = await ads.sponsoredSlot({
  context: { tool: "search_flights" },
  enabled: user.tier !== "paid",
});

Framework integrations

Result widgets — templates for your OWN tool output (0.8.5)

One widget, every host. The frame speaks three bridges — stable MCP Apps (ui/initialize, 2026-01-26), the draft-era fallback, and ChatGPT's window.openai — and the SDK registers both template keys (_meta.ui.resourceUri + openai/outputTemplate) and both CSP dialects automatically. Verified rendering live on claude.ai and ChatGPT, including the rendered-impression beacon (impressions count what a human actually saw, never mere API output). After upgrading, refresh your connector in ChatGPT's plugin settings — it caches tool metadata.

The SPONSORED strip's own format is separately configurable via sponsor_template= (independent of template=, this widget's own body layout):

register_result_widget(
    mcp, "search_flights",
    template="table-card",
    mapping={"rows": "flights", "columns": [...]},
    endpoint_url="https://my-server.example.com/mcp",
    sponsor_template="flip-card",  # or "carousel", "scratch-reveal" -- "card" is the default
)

Supported hosts

The plain sponsored JSON field is the always-on baseline: it ships on every tool result, on every MCP host, because it's nothing more than an extra key on a dict — no host-specific support is required for it to work, and the model decides on its own whether to surface it. The rendered MCP Apps widget above that is additive, and only paints where a host has actually implemented the ui/initialize handshake. This table says exactly which is which per host, based on our own production verification where we have it and a fresh survey (2026-08-25) everywhere else — a host only gets a "Live" widget status here when we've confirmed it ourselves or the vendor has published concrete, checkable implementation detail, never on a generic "should work" assumption.

_{Hosts we've looked at — logos are not a support claim on their own; read the Status column below for what each one actually does. (Continue.dev is in the table but not the strip above: it's a discontinued product, kept here only for completeness.)}

Why some hosts need zero extra code and others don't

Different hosts converged on different conventions for how a tool advertises "I have a renderable UI" — and where a host's convention differs from the one we shipped first, discovery silently fails before rendering ever gets a chance to run (that was the CopilotKit gap PR #8 fixed, 2026-08-25). We track each convention we've confirmed and register against all of them on every widget-capable tool — additive only, never a rewrite, so a host that doesn't recognize one signal just ignores it. That's the practical reason Claude and VS Code render with zero extra code (they share a convention) while CopilotKit needed a targeted fix, and it's why "no evidence found" in the table below means exactly that — evidence not found yet, not evidence of absence.

Anything else not listed above (LangGraph Studio, custom in-house agent harnesses, and every host we simply haven't looked at yet): unknown / not yet investigated — the plain sponsored field is designed to fail open and degrade gracefully on any of them regardless, per the Guarantees below. If you've verified rendering on a host not in this table, open an issue or PR — this list is meant to stay honest, not exhaustive.

This table is specifically about widget rendering in chat hosts. For the fuller picture — agentic SDKs/frameworks (most reach the data field via MCP passthrough, no dedicated adapter needed), response-suffix runtimes (WhatsApp/Telegram/Slack/SMS bots, background agents), AI app builders (not yet evaluated), and MCP hosting/registries (irrelevant to this SDK by design) — see Supported surfaces.

Don't design UI. Pick one of four predefined, host-native-quality result widgets and map your tool's structuredContent fields into it — the frame, design tokens, and the disclosed SPONSORED strip are fixed by the SDK. The strip renders only when a live sponsored payload exists, always at the bottom, always labeled, with the advertiser's logo (letter-tile fallback when none loads). Your body can't remove or restyle it.

Templates: stat-card (big value + chips + optional condition-keyed atmospheric background), table-card (headed rows, mono numerics, best-row highlight), notice-card (verdict glyph + detail rows), carousel-card (3–8 swipeable option cards).

from lulu_ads.widgets import register_result_widget

# after your @mcp.tool definitions:
register_result_widget(
    mcp, "get_weather",
    template="stat-card",
    mapping={
        "eyebrow": "location.name",
        "value": {"path": "temperature_c", "suffix": "°"},
        "condition": "conditions",
        "chips": [{"path": "humidity_pct", "prefix": "💧 ", "suffix": "%"}],
        "atmosphere": "weather_code",   # WMO code or words -> sky gradient
    },
    endpoint_url="https://my-server.example.com/mcp",
)

TypeScript: import { registerResultWidget } from "lulu-ads/widgets" — same templates and mapping shape; spread the returned _meta into server.registerTool(...). Mapping entries are dot-paths or {path, prefix, suffix}; a body_html= escape hatch accepts custom markup composed from the .lw-* primitives for the cases the templates don't cover. Calling it for a tool deliberately replaces the generic sponsored card from enable_lulu_ads on that tool — the sponsored data still flows and renders in the widget's own strip.

Widget rendering (MCP Apps UI)

The plain sponsored field always ships and always works — some hosts render it as a card purely on the model's own judgment, no instruction anywhere. For hosts that support the MCP Apps extension (io.modelcontextprotocol/ui), enable_lulu_ads / enableLuluAds (see Quickstart above) already register an actual rendered widget and attach it to every tool automatically — you don't need anything below this line for that. It exists as a distinct step at all because register_sponsored_widget() requires your server's exact public endpoint URL, which LuluAdsMiddleware/withLuluAds alone have no way to know.

Prefer per-tool control (a different widget on different tools, or only some tools get one)? Use the lower-level building block directly instead of enable_lulu_ads:

from fastmcp import FastMCP
from lulu_ads.widget import register_sponsored_widget

mcp = FastMCP("my-server")
sponsored_app = register_sponsored_widget(
    mcp,
    endpoint_url="https://my-server.example.com/mcp",  # your public MCP connector URL
    text="Save 15% at checkout",
    url="https://example.com/deal",
    logo="https://example.com/logo.png",  # optional, see "Logos" below
)

@mcp.tool(app=sponsored_app)
def search(...): ...

Same helper, official TS SDK, for MCP servers built in Node instead of Python (registration is async — it may fetch a logo before returning):

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { registerSponsoredWidget } from "lulu-ads/widget";

const server = new McpServer({ name: "my-server", version: "1.0.0" });
const appMeta = await registerSponsoredWidget(server, {
  endpointUrl: "https://my-server.example.com/mcp", // your public MCP connector URL
  text: "Save 15% at checkout",
  url: "https://example.com/deal",
  logo: "https://example.com/logo.png", // optional, see "Logos" below
});

server.registerTool("search", { ...appMeta }, handler);

Card formats. template= picks the widget's visual layout — a registration-time choice, same shape as register_result_widget's own template= (Result widgets, above). Defaults to "card" (the layout shown above); pass a different name for a different format:

sponsored_app = register_sponsored_widget(
    mcp,
    endpoint_url="https://my-server.example.com/mcp",
    text="Save 15% at checkout",
    url="https://example.com/deal",
    template="banner",  # full-width horizontal strip -- see Templates below
)

const appMeta = await registerSponsoredWidget(server, {
  endpointUrl: "https://my-server.example.com/mcp",
  text: "Save 15% at checkout",
  url: "https://example.com/deal",
  template: "banner",
});

An unrecognized template raises immediately (before any network call, e.g. the logo fetch) rather than silently falling back — same fail-fast contract register_result_widget's template validation already has.

"hero" accepts one more option, background_image/backgroundImage — a URL fetched once at registration time and inlined the same way logo is:

sponsored_app = register_sponsored_widget(
    mcp,
    endpoint_url="https://my-server.example.com/mcp",
    text="Save 15% at checkout",
    url="https://example.com/deal",
    template="hero",
    background_image="https://example.com/hero-bg.jpg",  # optional -- falls back to the gradient
)

Templates:

More formats land here as they ship (carousel, comparison, testimonial, countdown, quiz, video — see the gallery tracked in Linear). Every template shares the exact same guarantees: skeleton-on-load, the disclosed Sponsored label, the "Powered by Lulu Ads" footer, and fail-open on missing/malformed data — none of that is renegotiable per template.

This is also what enable_lulu_ads/enableLuluAds do internally, on your behalf, for every tool — found live (2026-07-26) that getting this step right per-tool is easy to forget: our own dogfood server had it wired onto exactly one tool by hand, and every tool added since then silently never got it. If you want automatic coverage with no per-tool step, use enable_lulu_ads/enableLuluAds instead of this directly.

Ships a floating, rounded, gradient card (same visual system as getlulu.dev) with a disclosed Sponsored label — still just markup, never a directive. Three host-specific quirks this handles for you: Claude requires an undocumented _meta.ui.domain value derived from your endpoint URL (self-computed here, not a credential), the widget must send a ui/notifications/initialized handshake on load or Claude keeps the iframe hidden, and logos are inlined rather than linked (next section) so the widget sandbox's own CSP can't silently drop them. Verified live against production (dali.getlulu.dev/mcp, ext-apps#671), current as of 2026-07-19 — Claude's own rendering of MCP Apps widgets was broken platform-wide before that fix landed, so treat any "should render" claim (including this one, elsewhere) as unverified until you've checked it live in your own host.

The widget shows a shadcn <Skeleton> immediately on load, then swaps to real content only once a live tool call arrives — text/url/logo passed to register_sponsored_widget() are not rendered as initial content; only label/cta/accent* from those options are actually used by the live path (as defaults for fields the wire payload omits, and as the static per-integrator brand theme). On every real tool call, the widget listens for the MCP Apps host's own ui/notifications/tool-result push (a fresh iframe is mounted per call, not reused — "per call, not per tool" is a protocol guarantee, nothing had to be built server-side to get it) and renders with that call's structuredContent.sponsored — live, per-call ad content, not a fixed payload baked in once at registration. A host that never sends the notification keeps showing the skeleton indefinitely (not a fallback ad — see the open gap noted in js/widget-src/src/mcpBridge.ts's InitialOptions docstring); a call with no sponsored field (the normal fail-open case) renders an empty card with only the footer. Card, skeleton, and the "Powered by Lulu Ads" footer are one compiled React/shadcn bundle shared byte-for-byte between the Python and TypeScript SDKs (js/widget-src/, checked in, embedded by both languages), and the footer always renders inside that same persistent card shell, in every state.

Logos

logo takes a URL to fetch a brand mark from, not a URL to embed directly — pass it and the SDK downloads the image right there at registration time and inlines it into the widget as a data: URI. This isn't incidental: the MCP Apps spec has hosts enforce img-src 'self' data: <resourceDomains> inside the widget's sandboxed iframe, and unless you separately declare your logo's domain in that resource's CSP config, a <img src="https://your-cdn.com/logo.png"> gets silently dropped — no error anywhere, the card just renders with a blank slot forever, in every host. data: URIs are always allowed under that same rule, so fetching and inlining server-side sidesteps the whole failure mode — there is no CSP config for you to get right or forget.

A bad or unreachable logo never breaks registration — it's skipped (with a warning log) and the card renders without one, same as leaving logo unset. Only image/png, image/jpeg, image/svg+xml, image/webp, and image/gif are accepted, capped at 200KB (the logo renders at 28×28 in the card — there's no reason to ship more than that over the wire).

CLI rendering

Terminals have no widget surface — the model's own text is the only output there is, and it's genuinely the model's judgment call whether to mention the disclosed line at all (never forced, ever — see Guarantees). LuluAdsMiddleware / withLuluAds detect known CLI clients via the MCP clientInfo.name sent at initialize (currently: claude-code, verified live) and, when connected from one, append a bordered plain-text card to content[] in addition to the plain field — still just data, still zero instruction to the model, just formatted so it reads as a distinct block instead of a plain sentence if the model does choose to relay it:

╭─ Sponsored ────────────────────────────────────╮
│ Search 700+ airlines in one place — Kiwi.com   │
│ finds routes other search engines miss.        │
╰─ via Lulu Ads ─────────────────────────────────╯
→ https://ads.getlulu.dev/c/9f2a1c

Known limitation, disclosed here rather than glossed over: some MCP clients don't forward every content[] block to the model when structuredContent is also present on the same result — an open client-side bug in Claude Code, twice reported and twice closed without a fix (#55677 → consolidated into #45575 → auto-closed stale). Live-tested against Claude Code specifically (2026-07-21): with structuredContent present (the shipped default), the boxed card never reaches the model, but the plain sponsored field still does — the model reliably surfaces it as an honest, labeled "Sponsored: ..." line in its own words, 3/3 runs, no issues.

cliTextMode — opt-in fix for the client bug above

We also tested the obvious-looking fix — omit structuredContent so content[] has nothing competing with it — and the result depended entirely on what else was in content[]:

• Ad alone, no real tool data alongside it: the card arrives every time, but the model flags it as a suspected prompt-injection attempt and warns the user off it, 3/3 runs. Worse than not showing it.
• Ad alongside a real, complete rendering of the tool's own result: the card arrives every time, the model treats it as an ordinary disclosed ad and mentions it neutrally, 3/3 runs. No suspicion.

So the fix is real, but conditional on your tool's own behavior — which this SDK can't verify for you, hence opt-in, off by default:

mcp.add_middleware(LuluAdsMiddleware(cli_text_mode=True))

withLuluAds(server, ads, { cliTextMode: true });

Turn this on only if your tool's content[] already contains a complete, human-readable rendering of the result on its own — not a placeholder like "see structuredContent". When on, detected CLI clients with no declared outputSchema get structuredContent stripped so content[] (your tool's own text + our card) reliably reaches the model. Tools that declare an outputSchema are never touched by this — stripping structuredContent there would break client-side schema validation outright (confirmed: fastmcp.exceptions.ToolError "outputSchema defined but no structured output returned"), which is a broken tool call, a strictly worse outcome than a dropped card. This SDK never drops structuredContent.sponsored on schema'd tools to chase card visibility, cliTextMode or not.

Until the upstream client bug is fixed, treat the CLI card as "renders reliably once you opt in and your tool qualifies, on top of a disclosure that already works either way" — same verify-in-your-own-host caveat as the widget path above.

stdio servers

Everything above the "Widget rendering" section works unmodified on a stdio-transport server — the SDK is a library your code imports and calls; it doesn't know or care how your own server talks to its clients. The plain sponsored data field (LuluAdsMiddleware / mcp.add_middleware(), withLuluAds(server)) takes no endpoint argument and makes a plain outbound HTTPS call to ads.getlulu.dev/slot — same request whether your process is a long-running remote server or a npx/uvx-launched local one. The CLI text-card path (see "CLI rendering" above) is the common real-world case here: Claude Code launches most of its MCP servers over stdio, and that's exactly the client this SDK already detects and renders a disclosed plain-text card for.

The rendered MCP Apps widget is the one piece that doesn't apply — enable_lulu_ads/enableLuluAds and the lower-level register_sponsored_widget/registerSponsoredWidget all require a real endpoint_url, hashed into Claude's undocumented _meta.ui.domain value for the widget's iframe CSP. That's not a Lulu Ads limit; MCP Apps' ui/initialize handshake is a network protocol between the host and your server's own HTTP endpoint, and a stdio server has none. If your server is stdio-only, call LuluAdsMiddleware/mcp.add_middleware() directly (or withLuluAds(server) in TypeScript) — never enable_lulu_ads — and you get the data field plus the CLI text-card, with nothing to configure for the endpoint you don't have.

Publisher-side note: the marketplace's automatic "monetized" badge currently matches a listing to your registered publisher account by remote_url — a stdio listing has none, so it won't auto-badge even once you've integrated the SDK and are earning. The SDK/earnings path itself is unaffected; this is purely a marketplace-listing display gap, being tracked separately.

Guarantees (enforced in code, not just promised)

Why not just…

…tell the model to mention a sponsor in its reply? Display instructions get MCP servers delisted by registries that scan for injected directives. We ship a plain data object — label, text, url — with no field, anywhere in the contract, that tells a model how to render or phrase anything.

…count impressions and charge per view? An "impression" only exists if a model actually rendered it, and that's unverifiable from the server side — easy to game, hard to audit. We charge CPA only, on a click that redeems a signed, server-verified token. Payment maps to a real user action, not a claim.

…scan the conversation to target better? Reading transcripts to target ads is a privacy trap: everything a user says becomes ad-targeting data. We accept six allowlisted context keys — tool, category, query, route, locale, country — stated intent for this call only. No transcripts, no profiles, no PII fields exist in the schema.

How it works

tool call
   │
   ▼
your tool's own result
   │
   ▼
POST /slot  (1500ms cap — 3000ms when classifying a raw prompt — allowlisted context only)
   │
   ▼
labeled data field  { label: "Sponsored", text, url }   ← attached, never injected
   │
   ▼
host / model judgment   →   renders it, or doesn't — not our call
   │  user clicks
   ▼
GET /c/{token}   →   signed redirect, click recorded
   │
   ▼
advertiser's affiliate rails   →   POST /postback on conversion
   │
   ▼
70% publisher / 30% Lulu, on the ledger. Earnings accrue to your balance from the first audited conversion — cash out from $100.

Full wire-level detail: docs/contract.md.

Docs: https://getlulu.dev/docs · Quickstart · API contract · Integrations · Publisher signup · Quality gate: Dali · MIT

Changelog

• 0.9.19 — Fixes what the SDK reported about itself.

  SDK_VERSION in the TypeScript client was a hardcoded "0.9.14" while the package moved through four releases — and it is sent to /slot as sdk_version, so every TypeScript publisher reported 0.9.14 and upgrade telemetry could not tell who had actually upgraded. Now correct, and pinned by a test against package.json so a release that forgets it fails the suite instead of quietly corrupting the data. The Python client never had this bug; it imports lulu_ads.__version__.

  Docs, no behaviour change: js/src/skybridge.ts's header still described the adapter as _meta-only, which stopped being true in 0.9.15 — it now carries the same four-case landing table as docs/integrations.md. And python/README.md, which is what PyPI renders, had no sync with the root README and had fallen four releases behind, so the package page described Skybridge using that same retired claim. Both package READMEs are now fed by scripts/sync-readmes.sh.

• 0.9.18 — Skybridge 2.x support, and a guard against its one silent failure.

  skybridge 2.x moved protocol-middleware wiring out of McpServer.connect() into the app's request path, so the attach point differs by major:

  ts

  Copy

  // 2.x — inside the app handler
  new Skybridge({ name, version, handler: (server) => {
    withLuluAdsSkybridge(server);
    return server.registerTool({ name: "t" }, handler);
  }});
  
  // 1.x — on the server you connect yourself
  withLuluAdsSkybridge(server);
  

  Using the 1.x shape on 2.x registers the middleware into a chain nothing applies: no error, no ad, nothing to debug. The adapter now detects that (its middleware always runs before a tool handler, so a tool executing while it never ran means it isn't wired) and warns once with the correct snippet. Warned, never thrown.

  Verified against both majors — 106/106 on skybridge@1.4.1 and @2.0.0, plus an end-to-end example run against the published package. Note that on 2.x an idiomatic content-only tool carries the ad on _meta alone, so a view should read structuredContent first and fall back to _meta; the reference view in examples/skybridge-views/ does exactly that.

• 0.9.15–0.9.17 — Skybridge delivers at all, and the SDK reports who is calling.

  On 2.0.1: these changes were briefly published as 2.0.1 before being retired — the major stranded every existing ^0.9.x dependency range, which meant nobody would have received them without hand-editing their package.json. It is yanked on PyPI and superseded on npm; use the 0.9.x line. Nothing was lost, only renumbered.

  Skybridge. withLuluAdsSkybridge used to attach sponsored to _meta only. Nothing on the Skybridge path reads _meta — enableLuluAds can't register a widget there (Skybridge's registerViewResource is private) and there's no CLI card — so the slot was fetched, logged, and surfaced to nobody. Probing the live result shape showed content[] arrives empty on Skybridge with structuredContent populated (the inverse of the official SDK), so structuredContent is what a view renders from. It now lands there:

  tool shape	sponsored goes to
  no outputSchema	structuredContent and _meta
  has outputSchema	_meta only — an unlisted field would fail the client's validation
  registered before withLuluAdsSkybridge	_meta only — schema status unknown, safe default

  The schema flag is captured at registration time via a 2-arg registerTool wrapper, since mcpMiddleware can't see outputSchema.

  Client identity. Every adapter now forwards the MCP client name as context.client, so ads-server can tell a real agent from a directory crawler. "client" joins the context allowlist. No integrator code changes.

  Two silent breakages fixed on fastmcp 4.x / MCP SDK v2. clientInfo was renamed client_info; the old spelling raised inside a bare except, so _connected_client_name returned None on every 4.x host — which also silently disabled the CLI sponsored card (is_cli_client(None) is False). And 4.x negotiates server/discover instead of initialize, so on_initialize never fired and the async warm-up stopped, handing back the cold-start latency the tiered-timeout work exists to avoid. Both accessors now try new-then-old spellings, and on_discover runs alongside on_initialize. Python suite: 144 passed / 0 failed on both 4.0.5 and 3.4.4 (was 8 failing). JS: 104/104.

  Upgrading: staying on the 0.9.x line is deliberate — a ^0.9.x range reaches 0.9.18, so npm update lulu-ads / pip install -U lulu-ads is enough and no dependency range needs editing. That propagation is exactly what the retired 2.0.1 would have cost.

  See examples/skybridge_server.ts and npm run verify:skybridge, which asserts all of the above against a real server over an in-memory transport.

• 0.9.14 — An ad's per-call template (LUL-64, when /slot reports one) now wins over the template=/template: you registered with, for the standalone sponsor-card widget (register_sponsored_widget()/ registerSponsoredWidget()). If it's absent or not a template this bundle build recognizes, it falls back to your registration-time default as before, then to "card". Behavior change on upgrade, no code change required: if you registered with a non-default template= (e.g. "hero"), ads that carry their own live template will now render in that template instead, with no opt-out. This is intentional — an admin picking a template for a specific ad is meant to be more specific than a blanket integrator default — but it does mean your widget's visual output can change after upgrading even though you changed no code. Also fixes a lookup hazard where a prototype-chain name (e.g. "constructor") in a live template value could be misread as "recognized" and crash the render after the impression beacon had already fired.

• 0.9.13 — Fixed a rendered-impression billing gap (LUL-71) in the standalone sponsor-card widget (register_sponsored_widget()/ registerSponsoredWidget() — the React-built card, banner, flip-card, scratch-reveal, spin, and hero templates): the wire payload's imp_url/ impUrl field was parsed and exposed by both clients (Sponsored.impUrl in the Node SDK, imp_url in the Python client) but silently dropped by the widget bundle's own message parsing before it ever reached the React components — so the rendered-impression beacon (a 1px <img> that confirms a human actually saw the ad, which CPM is billed against) never fired for this widget at all, for any template, since it shipped. Fixed centrally in App.tsx's loading→"loaded" transition — the same moment every template's disclosed content becomes visible, including flip-card's front teaser (fires before the user ever flips it, matching register_result_widget()'s footer strip's own already-correct behavior) and scratch-reveal's covered content (fires before anyone scratches). register_sponsored_widget()/registerSponsoredWidget() also now declare the ads.getlulu.dev resource/connect CSP domains the beacon pixel needs to not be silently blocked by a host's default img-src 'self' data: policy — the same declaration register_result_widget() already had. Verified live: the beacon fires a real HTTP request the instant a tool-result with imp_url arrives, confirmed via a local server's access log, not just unit tests.

• 0.9.12 — Result-widget footer sponsor_template= (LUL-69) redesigned from a slim single-line strip into a cover card: a colorful cover band — a real sponsor image when the live payload supplies cover_image_url/ coverImageUrl, an animated gradient otherwise — with the logo tile overlapping the seam into the body, bigger type, and a real pill CTA button. "flip-card"'s teaser now carries the same cover identity instead of a bare label. "spin" is removed: a coin-flip scaleX animation on a small, often-flat letter-tile logo turned out visually illegible in practice (mid-animation it shrinks to a near-invisible sliver against a busy cover background), caught live rather than inferred. It's replaced by "carousel" — auto-cycles through three framings of the same single sponsored payload (a bigger brand logo, the offer text, then the CTA), never multiple sponsors: this frame only ever gets one sponsored payload per call, so unlike the standalone gallery's carousel template there is no multi-advertiser rotation here (see LUL-49 for that separate, still-blocked, backend question). "scratch-reveal" is restyled as a lottery-ticket foil stub — gold metallic gradient, diagonal hatching, a dashed perforation line, a ticket glyph — and its auto-reveal window is 5s now, not 3s, long enough to actually register as an interaction; it remains a strictly deterministic reveal with no "win/lose" state, which is what keeps the ticket styling out of actual gambling-mechanic territory. The "single row, no room for a full-bleed image" reasoning that used to also exclude "hero" no longer holds now that the strip itself is cover-height — noted as an open follow-up, not resolved by this release.

• 0.9.11 — register_result_widget()/registerResultWidget() gain sponsor_template=/sponsorTemplate: (LUL-69): the SPONSORED strip built into a result widget's footer (stat-card/table-card/notice-card/ carousel-card — a publisher's own tool output, not the standalone sponsor-card widget) can now pick a visual format too, independent of template=, this widget's own body layout. "card" (default) is the original always-visible strip. "flip-card" is a compact "Sponsored" teaser that crossfades to reveal the real offer on tap — the front face carries an actual prompt ("Tap to reveal →"), not just a bare disclosure label, so there's a reason to tap it. "spin" is a decorative spin-settle flourish on the logo badge, content visible immediately, never gated (no variable outcomes — see the spin guardrail below). "scratch-reveal" is a canvas scratch-off layer, auto-revealing after 3s regardless of interaction — the offer underneath is identical whether or not anyone scratches. "banner"/ "hero" are deliberately not offered here: this strip is already one horizontal row (banner would be a no-op) and a full-bleed background doesn't fit a slim footer bar. This is a different system from the standalone sponsor-card gallery above (register_sponsored_widget()'s own template=) — same template names where they overlap, ported into this frame's own vanilla-JS renderer rather than sharing code, since the two frames are independent implementations by design.

• 0.9.10 — Four more templates: "flip-card" (LUL-53, a CSS 3D flip on tap revealing the offer on the back face — front always shows the disclosed label first, never hides what this is, only the offer details), "scratch-reveal" (LUL-52, a canvas scratch-off layer, auto-reveals after 3s regardless of interaction — the underlying offer is identical whether or not anyone scratches, this is a reveal animation, never gated content), "spin" (LUL-54, a decorative spin-and-settle flourish on the logo badge — deterministic by design, no wheel-of-fortune-style variable outcomes, since that would be a gambling mechanic), and "hero" (LUL-48, a full-bleed background image or gradient with logo/text/CTA anchored over a legibility scrim). register_sponsored_widget()/registerSponsoredWidget() also gain an optional background_image/backgroundImage param for "hero" — same fetch-once-and-inline-as-data:-URI contract logo already has (a fetch failure just falls back to the shared gradient, never a registration error). This is integrator-supplied, registration-time branding, same category as logo/accent* — not yet wired into ads-server's automatic per-campaign ad matching, which doesn't have an image field of its own (tracked separately).

• 0.9.9 — First real entry in the template gallery: template="banner" (LUL-47), a full-width horizontal strip (label, logo, text/CTA all in one row) instead of the default "card"'s stacked layout — better fit for wide-but-short surfaces (VS Code sidebar, wide CLI panes). Same shared contract as every template: renders inside the same persistent gradient shell, same disclosed label + "Powered by Lulu Ads" footer, same skeleton-on-load and fail-open behavior — nothing about those guarantees is template-specific. No background-image support yet (LUL-47's spec allows "image or gradient"; a real background-image field needs new schema on the advertiser side, tracked separately) — uses the existing accent-token gradient. Docs added: Widget rendering now documents template= with a live example and a table of available formats.

• 0.9.8 — register_sponsored_widget() / registerSponsoredWidget() gain a template= parameter (LUL-46), same shape as register_result_widget's: keyword-only, defaults to "card" (today's only format, fully backward compatible — no existing integrator's call site changes behavior), raises immediately on an unrecognized value (before any network call, e.g. the logo fetch). This is a registration-time integrator choice, not a per-call value — matches the static, "baked into the compiled bundle at registration" behavior register_result_widget's own template already has, not something that varies per served ad. Foundational only: the registry/dispatch mechanism in js/widget-src/ now supports looking up a template by name, but "card" (the existing hand-built layout) is still the only entry — more templates land in their own follow-up releases as they're built (banner, hero, carousel, comparison, flip-card, scratch-reveal, spin, testimonial, countdown, quiz, video). Also fixes a real, pre-existing drift: the TS SDK's own SDK_VERSION telemetry constant had been stuck at 0.9.0 since a much earlier release despite package.json moving on to 0.9.6 — realigned here, and the two packages' version numbers themselves are now back in sync (the previous 0.9.7 was Python-only; the TS package skips straight to 0.9.8).

• 0.9.7 (Python only) — CLI/text clients now get a delivery-confirmed beacon: the normal rendered-impression pixel (imp_url) is fetched by a rendering client itself the instant it displays the sponsored strip — terminal/CLI hosts (Claude Code and friends) have no rendering engine to do that, so every CLI-delivered card was previously invisible in ad_events, full stop, even on 100%-successful deliveries. The middleware now fires that same beacon URL itself (fire-and-forget, non-blocking, tagged src=cli_server) the moment it appends a card to a CLI client's content[], on both is_cli card-append paths (the middleware's own fetched slot, and a tool's pre-set sponsored). This logs as a new, distinct cli_card_delivered event — not impression_rendered, and never counted toward CPM billing/payout — a deliberately weaker signal than a real rendered-pixel hit: it proves the card left the server in the tool response, never that a human actually saw it. Needs no config; existing imp_url-carrying slots pick this up automatically. (ads-server: /i/{token} now accepts an optional src=cli_server query param to log the distinct event type.)

• 0.9.6 — Docs only: new Supported surfaces page sorting every agent surface (chat hosts, agentic SDKs/frameworks, response-suffix runtimes, AI app builders, MCP hosting/registries) by how it actually reaches the SDK — a direct adapter, MCP protocol passthrough (no adapter needed once a server has Lulu Ads wired in), the generic format_suffix contract, or genuinely not yet evaluated — same evidentiary bar as the rest of this repo. Also adds a "stdio servers" section clarifying the data-field path needs no endpoint_url and works unmodified on stdio-transport servers; only the rendered MCP Apps widget requires one and can't apply to stdio. Also fixes lulu_ads.__version__, which had drifted to 0.9.0 while the package published as 0.9.5 — same class of bug as the 0.7.0 entry below, recurred because nothing enforces the two staying in sync; consider that the next real gap to close here.

• 0.9.2 (Python only) — Fixed a middleware bug: a tool that sets its own sponsored field (a documented pattern for e.g. a category-specific cross-sell) triggered the "never overwrite" early return in on_call_tool before the CLI-client check ran, so CLI hosts (Claude Code) got no visible ad at all on that tool — no widget surface, and no text-card safety net either, both skipped by the same early exit. The client check now runs first; a pre-set sponsored value still gets the CLI text-card treatment, using the tool's own chosen ad.

• 0.9.1 — table-card widget gains rowLink: an optional per-row dot-path resolving to a URL (e.g. a booking/checkout link), wired to the same host-agnostic openLink() the sponsored strip already uses. Rows without a resolvable URL render exactly as before.

• 0.9.0 — Skybridge (https://skybridge.tech) support: withLuluAdsSkybridge(server) (lulu-ads/skybridge). Skybridge's McpServer.registerTool takes a 2-arg (config, handler) shape with name folded into config, not the official SDK's 3-arg (name, config, handler) that withLuluAds wraps — reusing withLuluAds as-is would misread the config object as the tool name. The new adapter instead uses Skybridge's own mcpMiddleware("tools/call", ...) protocol hook, verified against the real skybridge@1.4.0 package's shipped types and a live InMemoryTransport round-trip. Deliberately _meta-only: the middleware sees the call result but not the tool's registered outputSchema, so structuredContent is never touched.

• 0.8.1 — Result-widget template gallery (supersedes 0.8.0, which briefly shipped on npm with a louder strip design): lulu_ads.widgets / lulu-ads/widgets with four predefined templates (stat-card, table-card, notice-card, carousel-card), design tokens + .lw-* primitives, and the disclosed SPONSORED strip built into the frame (advertiser logo via the slot's new logo_url, letter-tile fallback). register_result_widget() patches an already-registered FastMCP tool in place (or returns the AppConfig for explicit app=).

• 0.7.4 — Widget: the sponsored card's iframe canvas no longer paints an opaque white box on dark hosts. background: transparent alone is not enough for an embedded iframe: Chromium keeps the canvas transparent only when the embedded document's used color scheme matches the embedder's, and this document declared none (defaulting to light), so dark-themed hosts (e.g. claude.ai in dark mode) forced a white backdrop behind the card. The widget now declares color-scheme: light dark, which resolves to the user's preferred scheme — matching hosts that follow it (claude.ai does by default) on both light and dark themes. Verified empirically against light- and dark-scheme embedding pages. (Also aligns lulu_ads.__version__, which had drifted to 0.7.2 while the packages published as 0.7.3.)

• 0.7.0 — Two real bugs, found live against a real third-party MCP server behind Claude.ai's remote connector, both fixed:

  • 0% ad delivery on hosts that reconnect per message (confirmed: Claude.ai opens a brand-new MCP session per chat message, not once per conversation). Root cause: this SDK's persistent HTTP connection goes cold on any real idle gap between messages, but only a one-time "have I ever succeeded" check protected the very first call ever — every later cold call still got the tight steady-state timeout and failed. Fixed by re-checking coldness on every call, keyed to time since the last real success, not a permanent latch. Also: the fast steady-state timeout itself was raised 800ms → 1500ms (Python and TS) — production evidence showed even "warm" calls sometimes measuring 796-802ms, right at the old line rather than comfortably under it.
  • Ad fetched successfully, never seen by the model. FastMCP/the MCP TS SDK build a tool result's content[] once, from the tool's original return value, before LuluAdsMiddleware/withLuluAds ever run — mutating structuredContent alone (the only thing this SDK's own test suite checked) left content[] permanently stale. Confirmed live: the wire response's structuredContent demonstrably had sponsored, but Claude.ai read and reported back from content[], which didn't. Both SDKs now keep content[] in sync whenever it's safe to (a single auto-generated JSON text block); regression tests added for the exact gap that let this ship unnoticed the first time.
  • New: enable_lulu_ads() (Python) / enableLuluAds() (TS) — one call that wires both the data field AND the rendered MCP Apps widget onto every tool automatically, present and future. Existing register_sponsored_widget()/registerSponsoredWidget() + app=/_meta.ui per tool still works and is now documented as the lower-level building block for per-tool control; the gap it left (an easy-to-forget manual step per tool) is exactly what this closes — found live on our own dogfood server, which had wired the widget onto exactly one tool by hand and silently never updated it for tools added since.

• 0.6.2 — The sponsored card now plays a one-time diagonal light sweep across itself when it settles into the loaded state (a real ad won) — pure CSS (.card-shine in js/widget-src/src/index.css), fires exactly once per mount (not a looping shimmer, since this sits inline in a real chat thread), and respects prefers-reduced-motion. Skeleton and no-fill states are unaffected.

• 0.6.1 — Corrects a stale 0.6.0 published to npm before dist/ was rebuilt from the merged source (js/ has no prepublishOnly build step) — 0.6.0 is deprecated on npm pointing here. Also fixes README.md and both languages' widget.py/widget.ts docstrings, which incorrectly claimed text/url/logo passed to register_sponsored_widget() render as a fallback "house ad" until a live tool-result arrives; they never do — the widget shows the skeleton indefinitely if a host never pushes it.

• 0.6.0 — The MCP Apps sponsored widget now shows live, per-call ad content instead of a fixed house ad baked in at registration time: rebuilt in React + shadcn/ui (Card, Skeleton, Button), compiled to a single self-contained bundle shared byte-for-byte by both SDKs (js/widget-src/). The widget shows a skeleton immediately on load, then listens for the MCP Apps host's own ui/notifications/tool-result push — which the spec already delivers once per call, to a fresh iframe per call, with no server-side change needed — and swaps to that call's real structuredContent.sponsored data — the widget shows the skeleton indefinitely if a host never pushes it, not a fallback ad; only label/cta/accent* from register_sponsored_widget()/ registerSponsoredWidget()'s options are actually used by the live path. The "Powered by Lulu Ads" footer renders once, immediately, and is never itself part of the skeleton→card swap. Live-verified against a real host (claude.ai) with a throwaway test server: skeleton renders before the tool call resolves, swaps to the real per-call card once it does, the footer never disappears or reflows during the swap, and two tool calls in the same turn render two fully independent widget instances, each showing only its own call's data — confirming the "per call, not per tool" behavior this feature is built on. (The CTA's ui/open-link redirect — vs. a raw navigation — was re-confirmed by static code inspection and this repo's existing unit tests during this same pass; live click-through capture was attempted but blocked by browser-automation tooling limits reaching inside the host's double-sandboxed iframe, not by any observed product failure.)

• 0.4.0 — Automatic pre-connect on construction for LangChain's LuluAdsAgentMiddleware, CrewAI's install(), and TypeScript's withLuluAds (matching the FastMCP LuluAdsMiddleware, which already had this). Also: FastMCP's LuluAdsMiddleware and LangChain's LuluAdsAgentMiddleware now additionally warm the async connection pool their awaited sponsored_slot() traffic actually uses — the construction-time warm-up above only ever touched the sync client, a separate pool the async path never touches. LuluAds.async_warm_up() is fired once per instance from a real framework lifecycle hook on the live serving event loop (FastMCP's on_initialize, LangChain's abefore_agent), since a background thread can't safely pre-warm a connection meant for a different event loop. Gated by the same auto_warm_up flag as the sync warm-up (this async path is Python-only — TypeScript's autoWarmUp only ever had one pool to gate). This is the fix that closes the cold-start gap for dali-mcp in production, which consumes the async path. Short-TTL (default 45s) success-only cache in both base clients, keyed on resolved category or a hash of the prompt text. Corrected documentation: the real default timeout is 800ms (fast path) / 3000ms (classify path) adaptive, not a flat 300ms.

• 0.3.7 — cliTextMode (opt-in, off by default): fixes the Claude Code content[]-drop bug for real, but only for tools whose content[] already stands on its own without structuredContent — live-tested both qualifying and non-qualifying cases, see "CLI rendering". Never touches tools with a declared outputSchema (would break client-side schema validation, confirmed via fastmcp.exceptions.ToolError).

• 0.3.6 — automatic connection warm-up on LuluAdsMiddleware construction (auto_warm_up, on by default): a genuinely cold first tool call measured 804ms against the 800ms fast-path default — right at the ceiling, not under it. LuluAds itself still never auto-warms (a network call as a constructor side effect is surprising in a general-purpose client), but the middleware is the "one line, zero config" promise, so it warms itself.

• 0.3.5 — fixed a hardcoded 300ms default timeout_ms on LuluAdsMiddleware that silently dropped real, fillable ads on real network latency — every test in the suite used an instant mock transport, which is exactly why this shipped unnoticed. Default is now None, deferring to LuluAds's own conditional 800ms/3000ms default.

• 0.3.4 — CLI card gets rounded corners and a "via Lulu Ads" footer (Unicode box-drawing only — a live test against Claude Code confirmed it strips raw ANSI color escapes from tool output before the model sees them, so color was never on the table). Also live-tested and explicitly rejected dropping structuredContent to force content[] through: it does make the card arrive, but the model then flags it as suspected prompt injection and warns the user off it — worse than the status quo, where the plain field still gets surfaced honestly even without the card. See "CLI rendering" for the full writeup.

• 0.3.3 — CLI-adaptive rendering: LuluAdsMiddleware / withLuluAds detect known CLI clients via the MCP clientInfo.name sent at initialize (currently: claude-code, verified live) and append a bordered plain-text card to content[] for them, in addition to the plain field — terminals have no widget surface, so this is the CLI-safe equivalent of the MCP Apps widget above. Still just data; see "CLI rendering" for the disclosed known limitation on some clients' content[] forwarding.

• 0.3.0 — register_sponsored_widget() / registerSponsoredWidget() gain a logo option: fetched server-side at registration time and inlined into the widget as a data: URI, so it renders under the widget sandbox's CSP (img-src 'self' data: <resourceDomains>) with no resourceDomains config needed on your part — a raw remote logo URL would otherwise be silently dropped, with no error anywhere. A bad/unreachable logo never breaks registration; the card just renders without one. TypeScript's registerSponsoredWidget() is now async (it may need to fetch the logo before returning) — add await at existing call sites.

• 0.2.0 — register_sponsored_widget() (Python: lulu_ads.widget, now also TypeScript: lulu-ads/widget, official MCP SDK): registers a real rendered MCP Apps UI sponsored card on your server (not just the plain JSON field), handling Claude's undocumented iframe-domain requirement and the ui/notifications/initialized handshake for you. Generalizes the fix verified live on dali.getlulu.dev/mcp against ext-apps#671. Both SDKs produce byte-identical _meta.ui.domain values for the same endpoint URL.

• 0.1.1 — persistent HTTP clients in the Python SDK (per-call client construction could burn the entire slot budget on CPU-constrained containers; clients are now created once per LuluAds instance and reused with keep-alive). Fail-open behavior unchanged.

• 0.1.0 — initial release: Python + TypeScript clients, FastMCP / LangChain / LangGraph / CrewAI / MCP-TS adapters, suffix helpers, MCP concierge onboarding.