PPP rebalance

You are helping the user rebalance their iOS app's subscription prices across App Store territories using a Purchasing Power Parity index. The appstoreconnect-mcp server is connected and provides the necessary tools.

The MCP does the math for you — ppp_compute_proposal is the single tool that produces the dry-run table. Your job is to drive the conversation, validate the proposal with the user, and apply it via the write tools.

Workflow

Run these phases in order. Never skip the dry-run.

1. Discover the subscription

If the user hasn't named the app + subscription:

1. asc_list_apps — find the app (filter by bundle ID if known).
2. asc_list_subscription_groups for that app.
3. asc_list_subscriptions for the relevant group.
4. Confirm with the user which subscription is being repriced and the anchor base price (e.g. $29.99 USD).

2. Compute the proposal (dry-run)

ppp_compute_proposal(
  subscriptionId: "...",
  basePriceAnchor: 29.99,
  anchorTerritory: "USA",
  roundStrategy: "nearest"   // or "down" / "up"
)

The tool:

• Fetches the current price schedule for every territory.
• Loads the bundled Apple Music index (ppp_load_index shows the snapshot).
• Computes a PPP factor per territory using Apple Music ratios as implied PPP-FX.
• Fetches the valid price points for every territory whose target differs from current, in parallel.
• Snaps each target to the nearest valid Apple price point.
• Applies a 15% floor (floorFactor) so a bad index entry can't crash the price.
• Returns a compact table with current, target, snapped, Δ%, factor, and a NOTE column for skipped/no-data rows.

Show the table to the user. Stop and wait for explicit approval before any writes.

3. Iterate the proposal if needed

If the user wants to tweak:

• Different round strategy: re-run with roundStrategy: "down" (more conservative for emerging markets) or "up" (more revenue-protective).
• Subset of territories: pass territories: ["BRA", "MEX", "ARG", "TUR", "IND", "IDN"] to scope the proposal.
• Different base price: change basePriceAnchor.
• Show all rows including unchanged: pass skipUnchanged: false.
• Surface no-index rows: pass skipMissingIndex: false so the user can see which territories Apple Music data is missing for.

4. Apply (preferred path)

Use the single-tool flow whenever possible:

ppp_apply_proposal(
  subscriptionId: "...",
  basePriceAnchor: 29.99,
  anchorTerritory: "USA",
  roundStrategy: "down",
  // Optional. Defaults shown.
  // startDate: "<YYYY-MM-DD>",       // default: today + 7 days
  // preserveCurrentPrice: true,
  // floorFactor: 0.15,                // hard lower bound vs current local price; 0.30 is more conservative
  // maxConcurrency: 2,
  // maxDropPct: 90,
)

What it does:

1. Re-computes the proposal with the same inputs (so what you confirm is what gets written).
2. Refuses if any row drops by more than maxDropPct (default 90%) — guards against bad index data.
3. Asks the user to confirm via MCP elicitation — the client renders a confirmation form with the diff. The user clicks "Apply" or "Cancel".
4. On confirm, POSTs all changes in parallel at maxConcurrency (default 2). The HTTP client transparently retries on Apple's 429 rate limits with exponential backoff.
5. Skips territories where the ASC billing currency differs from the Apple Music index currency (marked currency-mismatch); set those manually if you want to.
6. Returns a per-row status table (applied / failed with error).

If the client doesn't support elicitation, the tool returns the proposal and instructs the caller to re-run with confirm: true.

4b. Apply (manual fallback)

If you specifically need per-row control (debugging, partial apply, etc.), call asc_post_subscription_price for each row from the proposal:

asc_post_subscription_price(
  subscriptionId: "...",
  territoryId: "<3-letter code>",
  pricePointId: "<POINT_ID from proposal>",
  startDate: "<YYYY-MM-DD>",
  preserveCurrentPrice: true
)

• Always pass preserveCurrentPrice: true unless the user explicitly says otherwise — grandfathers existing subscribers.
• Skip rows with a NOTE (no-index, no-current-price, no-price-points, snap-failed, unchanged).
• On the first failure, stop and ask the user — don't continue through the list.

5. Verify

After the apply, re-run asc_list_subscription_prices and confirm the pending schedule matches the proposal. The new entries will have a non-null START_DATE.

6. Rollback (if needed)

If the proposal turns out wrong before activation:

1. asc_list_subscription_prices — find the pending entries (future startDate).
2. For each unwanted entry, asc_delete_subscription_price with the PRICE_ID.
3. Re-run asc_list_subscription_prices to confirm the schedule is clean.

Gotchas

These have bitten people doing this before; cite them when relevant:

• Always `preserveCurrentPrice: true` on writes. Otherwise existing subscribers re-price at next renewal — notifications + possible Apple rejection.
• Russia (`RUS`): App Store closed. The proposal will likely include it; skip the apply step for RUS.
• USD-only territories (e.g. some MENA + Pacific markets): the proposal will mark them as currency-mismatch (asc=USD, am=BHD) etc. and skip them from the apply set. This is intentional — multiplying a USD anchor by a (BHD/USD) ratio and writing the result back as USD is dimensionally wrong, so the formula doesn't apply. If you want to set prices for those markets, do it manually via asc_post_subscription_price after deciding on a number outside the PPP formula.
• Snap direction surprises: nearest can land above target. If the user wants emerging-market prices to drop, recommend roundStrategy: "down".
• Start date min lead time: Apple requires ≥24h. The skill defaults to 7 days.
• Apple gives no batch endpoint: each territory is one POST. ~14 emerging markets = ~14 sequential calls.
• Apple Music index is a snapshot — the bundled data/apple-music-prices.json is refreshed manually upstream. Show the snapshot date when presenting the proposal so the user can decide whether to refresh it first.

When NOT to use this skill

• Cracking the price for a new subscription before launch — call asc_post_subscription_price directly without PPP factors; the initial schedule is a one-shot decision.
• Reshaping introductory offers, free trials, or promo codes — those are different ASC resources and not covered here.
• Currency-specific tax adjustments — Apple handles tax automatically per region.