baya-monorepo/mvp/blocker-phases/08-refunds-demock.md

Phase 08 — Refunds are demo-only, and off by 100×

Blocker: blockers.md § "Payments" (refunds). Depends on: nothing.

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Root cause — the mock. client/src/services/refunds/constants.ts:18 — USE_REFUNDS_MOCK = true. The real server side (RefundsController.cs, CreateRefundCommand, GetCancellationPolicyPreviewQuery) is live and correct; the client just never calls it for anything but the bare status read.

Root cause — the ×100 bug, exact. The server's refundPercentageApplied/feePercentage are 0–100 values (GetCancellationPolicyPreviewQuery.Handler.cs:74: 100m - policy.RefundPercentage). The client's own type comment claims 0–1 (refunds/types.ts:110-112) — true of the mock (MOCK_POLICY_TIERS, refunds/constants.ts:45-52, uses 1 | 0.5 | 0) but not the real server. The render function (CancellationPolicyDisclosure.tsx:19-21,36-37) does Math.round(fraction * 100) — correct by luck against the mock's 0–1 scale, but against the real server's 100.00 it produces "10000%".

Important nuance: the actual IRR amounts shown are server-supplied strings passed straight through — not multiplied by 100 themselves. It's specifically the percent-chip labels that are 100× too large.

The fix

1. Flip USE_REFUNDS_MOCK to false — the real endpoints are live and correct.
2. Fix the scale mismatch at the contract level, not just the one render site: type CancellationPolicyPreview.refundPercentageApplied/feePercentage as 0–100 (matching the real server), fix CancellationPolicyDisclosure.tsx's toPercent to stop re-multiplying an already-0–100 value, and fix the mock (mockApi.ts:127-128, MOCK_POLICY_TIERS) to also emit 0–100 so mock and real can never silently disagree on scale again. Check refunds/types.ts:167,201 for other render sites reusing the same field before considering this fully closed.
3. Same cross-mock-import problem as BNPL (phase 05): refunds/apis/mockApi.ts:3 imports directly from the (real) bookings mock store — moot once step 1 lands.