Auditing FBA Reimbursements: What Amazon Owes You

An FBA reimbursement audit sorts every lost or damaged Fulfillment by Amazon (FBA) unit into one of Amazon's four claim types, checks it against that type's window and seven eligibility conditions, and values it at sourcing cost or refund minus fees. An agent on the Selling Partner MCP pulls the reports; you file the resulting list in Seller Central.

The question usually arrives from finance: how much has Amazon already reimbursed us for lost and damaged inventory, and how much could we still claim? The Inventory Defect and Reimbursement (IDR) portal answers part of it. Amazon's help page says it applies the reimbursement policy checks to warehouse lost, warehouse damaged and customer-return defects, and sorts them into Eligible for Claim, In Progress and Resolved. Inbound shipment and removal losses live elsewhere.

The gap is the join. The windows start from different dates, the value depends on a sourcing cost only you hold, and the IDR portal has no API. Amazon Agent Atlas supplies Amazon's text for each claim type, the agent reads your reports through the Selling Partner MCP, and a Skill your team writes holds what you file first. The agent files nothing; the list is yours to submit.

Atlas grounds four FBA claim types, and each one runs its own clock

Amazon's FBA inventory reimbursement policy routes every claim to one of four pages, and each page sets its own window. Atlas retrieves all four from the amazon_sellers collection, so the agent quotes Amazon's dates rather than a remembered average.

The customer-return and lost-removal windows have a floor as well as a ceiling: a customer-return claim filed on day 30 is too early. A shipment claim opens only once the shipment shows as eligible for investigation. The agent computes each event's opening date, closing date and status, open, not yet open, closing soon or expired, as fields in the audit. An illustrative record, as of August 7:

{
  "event_id": "EVT-00113",
  "classified_claim_type": "fulfillment_center_operations",
  "reported_date": "2026-06-12",
  "window": { "opens": "2026-06-12", "closes": "2026-08-11", "status": "closing_soon", "days_remaining": 4 }
}

The Selling Partner MCP checks the eligibility conditions your data can show, and flags the rest for a person

Amazon does not reimburse partial eligibility. Its policy lists seven conditions that must all be true, and a claim that fails one is ineligible whatever the unit was worth. Six of the seven can be checked against data the Selling Partner MCP returns. The seventh cannot.

Before any event counts as recoverable, the agent also checks GET_FBA_REIMBURSEMENTS_DATA. That report lists every reimbursement, including the ones Amazon generated automatically, and each shipment-to-Amazon and removal claim page tells you to check it first. The IDR portal's Resolved tab already shows ineligible defects with Amazon's reason. The audit applies the same conditions before you file, across inbound and removal events too, and names the condition that failed.

A Skill your team writes values each event by when the loss happened, not by retail price

Amazon values a claim by whether the loss happened before or after a customer ordered the unit. The rules the agent applies:

• Pre-order losses (shipment to Amazon, removals, fulfillment center operations) pay your sourcing cost: what you paid a manufacturer, wholesaler or reseller, or your cost to make it. Shipping, handling and customs duties are excluded.
• An already-unsellable unit that is lost, damaged or removed pays a reduced estimated cost.
• Customer-return losses pay the refund amount, or the replacement price on the original order, minus applicable fees.
• Every reimbursement is capped at $5,000 per unit. Above that, Amazon recommends considering third-party insurance.

Amazon can also replace a lost unit with a new one of the same product instead of paying cash, which the Reimbursements report records in quantity-reimbursed-inventory.

The sourcing cost is where a Skill your team writes earns its place. If you never submit a cost on the Manage Your Sourcing Cost page, Amazon uses its own estimate from comparable products. That page has no API, so the Skill holds your documented costs from your own records, and the agent compares them with amount-per-unit on each reimbursement line.

A gap is a reason to submit your cost, with the documents Amazon may ask for. An illustrative audit report:

{
  "artifact_type": "audit_report",
  "rules": "a Skill your team writes",
  "grounded_by": "amazon-agent-atlas",
  "summary": {
    "events_audited": 214,
    "reimbursed_total_usd": 8420.15,
    "eligible_unclaimed_total_usd": 1180.40,
    "at_risk_window_closing_usd": 340.00,
    "disputable_valuation_total_usd": 265.75
  },
  "events": [
    {
      "event_id": "EVT-00113",
      "classified_claim_type": "fulfillment_center_operations",
      "order_relationship": "pre_order",
      "valuation": {
        "rule_applied": "sourcing_cost",
        "your_sourcing_cost_usd": 14.20,
        "cost_submitted_to_amazon": false,
        "unit_cap_usd": 5000
      },
      "status": "eligible_not_filed",
      "flags": ["window_closes_in_4_days", "sourcing_cost_not_submitted"]
    },
    {
      "event_id": "EVT-00087",
      "classified_claim_type": "customer_return",
      "order_relationship": "post_order",
      "valuation": { "rule_applied": "refund_minus_fees", "refund_amount_usd": 42.00, "fees_deducted_usd": 6.30 },
      "reimbursement_actual": { "issued": true, "amount_usd": 30.00, "variance_vs_expected_usd": -5.70 },
      "status": "disputable",
      "flags": ["valuation_dispute_window_open"]
    }
  ]
}

Filing stays with you: no Selling Partner API operation files a claim, so the agent tracks what is still open

The Selling Partner MCP has no operation that files an FBA reimbursement claim, opens a case, submits a sourcing cost or disputes a valuation. The one createClaim in the API belongs to Amazon Shipping labels, not FBA inventory. So the agent prepares each claim's inputs and you submit it in Seller Central:

• Fulfillment center operations: the FNSKU for a lost unit, or the transaction item ID from the Inventory Ledger for a damaged one.
• Customer return: the order ID.
• Shipment to Amazon: the shipment ID, proof of ownership and proof of delivery. Amazon accepts one claim per shipment and declines any after it, so the agent bundles every unit from that shipment into one claim.

Filing does not close the audit. Amazon may decline a cost update or a reimbursement-amount dispute for an item it decided on in the last 30 days, unless you add new information. A customer-return valuation dispute goes to Contact Us within 60 days after the reimbursement. If a reimbursed unit is later found, Amazon reserves the right to reverse the credit, and the adjusting line carries original-reimbursement-id.

Customer returns branch three ways. A refunded unit not back within 60 days is, in most cases, charged to the customer and reimbursed to you. One back within 60 days and sellable returns to inventory with no reimbursement. One back unsellable because of Amazon is reimbursed and not restocked; one damaged by the customer or defective is not reimbursed.

What happens next: land the reports in Amazon Agent Flow and rerun the audit each week

Amazon Agent Flow pulls the reimbursement, ledger, returns and removal reports on a schedule into a data lake you own, beside the advertising data the Amazon Ads MCP reads. The agent reruns the audit against fresh tables when you ask, or on the weekly prompt your automation tool already sends. Each run flags what changed:

• a window closing inside seven days
• a customer return crossing day 60, so its claim is now open
• a sourcing cost still missing for a reimbursed unit

For returns alone, the published Refund and Return Monitor Skill (a Reference Skill) flags damaged-versus-reimbursed review candidates. The other half of the FBA ledger, what you pay Amazon rather than what it owes you, is in the FBA inventory health guide.

Amazon publishes the rules and tracks the defects, and the filing stays with the seller.

Next in the series: the storage, capacity and aged-inventory fees on the other side of the FBA ledger.