selver-cart

name	selver-cart
description	Use this skill when the user wants to shop at Selver.ee - search products, build a cart, and open it in the browser for checkout. Handles weight-based goods (kg products with weight_step) and coordinates selver-mcp + chrome-devtools-mcp so the cart actually appears in the browser ready for checkout.

Selver Cart Workflow

The user is shopping at Selver.ee (Estonian grocery chain). Two MCPs work together:

• selver-mcp - builds the server-side guest cart via Selver's API
• chrome-devtools-mcp - opens the cart in a real browser so the user can log in and check out

Neither MCP alone is enough. Always orchestrate both.

When to use

Trigger on any request like:

• "Add X to my Selver cart"
• "Find me some Y at Selver and buy them"
• "Open my Selver cart"
• "Osta Selverist..." (Estonian: shop from Selver)

Workflow

1. Search

Call mcp__selver-mcp__search_products with an Estonian query when possible (leib, kana, kurk, piim, muna).

Inspect the results. Note especially: weight_step.

2. Handle weight-based products

If weight_step is not null (e.g. cucumbers, tomatoes, meat sold by kg):

• qty MUST be a multiple of weight_step (e.g. weight_step: 0.3 → valid qty: 0.3, 0.6, 0.9, ...)
• Integer qty will fail with "Toote samm on muutunud"
• When the user says "one cucumber", translate to the smallest reasonable multiple (usually 1 * weight_step, or ask if a typical single item is larger)

If weight_step is null: product is sold per-unit, use integer qty.

3. Add to cart

Call mcp__selver-mcp__add_to_cart with the SKUs and correct qty.

Check the response:

• Any items in failed? Read error - it now contains Selver's actual server message (e.g. step violations, stock issues).
• If weight-step violation, retry with the correct multiple.
• Save the cart_token - you'll need it to open the cart in the browser.

4. Open the cart in the browser (REQUIRED after any cart change)

The user wants to SEE the cart. Server-side cart is not enough. Orchestrate via chrome-devtools-mcp:

Step A: Open selver.ee (establishes the origin):

mcp__chrome-devtools__new_page url="https://www.selver.ee"

Step B: Set the cart token in localStorage:

localStorage.setItem('shop/cart/current-cart-token', JSON.stringify('<CART_TOKEN>'));

(via mcp__chrome-devtools__evaluate_script)

Step C: Navigate to the cart page:

mcp__chrome-devtools__navigate_page type=url url="https://www.selver.ee/cart"

Step D: Replay server items through the SPA's own add-to-cart flow (this is the critical step - without it, the SPA shows an empty cart even though the server has items).

Important: skip any SKU that's already in cartItems. Otherwise cart/addItem adds to the existing qty (e.g. cart shows 1.2 kg cucumber instead of 0.6) - because the SPA's add flow is "merge qty", not "replace". This matters both on fresh sessions (where the SPA's boot pull may have populated some items) and on subsequent add_to_cart calls to a browser that's already open.

async () => {
  const store = document.getElementById('app').__vue__.$store;
  const token = JSON.parse(localStorage.getItem('shop/cart/current-cart-token'));
  const res = await fetch(`/api/cart/pull?cartId=${token}&storeCode=et`);
  const serverItems = (await res.json()).result;

  const added = [], skipped = [], mismatched = [];
  for (const serverItem of serverItems) {
    const existing = store.state.cart.cartItems.find(i => i.sku === serverItem.sku);
    if (existing) {
      if (Math.abs(existing.qty - serverItem.qty) > 1e-4) {
        mismatched.push({ sku: serverItem.sku, client_qty: existing.qty, server_qty: serverItem.qty });
      } else {
        skipped.push(serverItem.sku);
      }
      continue;
    }
    const variant = await store.dispatch('cart/getProductVariant', { serverItem });
    if (variant) {
      await store.dispatch('cart/addItem', {
        productToAdd: variant,
        forceServerSilence: true,
      });
      added.push(serverItem.sku);
    }
  }
  await store.dispatch('cart/syncTotals', { forceServerSync: true });
  return { added, skipped, mismatched, total: store.state.cart.cartItems.length };
}

The snippet returns {added, skipped, mismatched}. If mismatched is non-empty, the client and server disagree on qty for some SKU - usually means the server-side add_to_cart added more after the browser was already open. To reconcile: call cart/updateItem with the server qty, or let the user decide.

Confirm the cart shows real products with correct prices. Tell the user to log in and check out.

5. Keeping an open browser in sync

If the browser is already open with items shown:

After calling add_to_cart - replay only the newly added items through the snippet above.

After calling remove_from_cart - also dispatch the SPA's removeItem in the browser, otherwise the removed items stay visible:

async () => {
  const store = document.getElementById('app').__vue__.$store;
  const skusToRemove = ['<SKU1>', '<SKU2>'];
  for (const sku of skusToRemove) {
    const item = store.state.cart.cartItems.find(i => i.sku === sku);
    if (item) await store.dispatch('cart/removeItem', { product: item });
  }
  return { remaining: store.state.cart.cartItems.length };
}

Common pitfalls

• "Toote samm on muutunud" - qty is not a multiple of weight_step. Read the step from the error message (e.g. "(0.3)") and retry.
• Cart looks empty in browser - Step D wasn't run, or was run too early (before the cart page loaded). Wait for the page to settle before the fetch.
• Cart shows items but qty controls spin - items weren't added via getProductVariant + addItem {forceServerSilence: true}. Internal flags missing. Always use the canonical snippet.
• Chrome already running error - if chrome-devtools-mcp complains about an existing browser instance, use list_pages to find the selver.ee tab and use select_page to work with it; don't call new_page again.

Example: full session

User: "Add 2 loaves of bread and half a kg of cucumber to my Selver cart and open it."

1. search_products(query="leib") - pick 2 loaves, note their SKUs.
2. search_products(query="kurk") - pick a cucumber sold by kg, note weight_step: 0.3.
3. add_to_cart(items=[{sku: bread1, qty: 1}, {sku: bread2, qty: 1}, {sku: cucumber, qty: 0.6}]) - note cart_token.
4. chrome-devtools-mcp: open selver.ee, set token in localStorage, navigate to /cart, run the replay snippet.
5. Tell user: "Your Selver cart has 2 loaves of bread and 0.6 kg of cucumber (€X.XX total). The cart is open in your browser - log in to complete checkout."