shopify-operations-mcp

Safe-write MCP server for Shopify Admin API operations — an agent can read and modify a Shopify store without being able to cause an unrecoverable accident. The safety layer is the differentiator: every write previews before it commits, large or irreversible changes require out-of-band human approval, and every action is recorded to a tamper-evident hash-chained audit file.

Architecture

flowchart TB
    subgraph agent["Agent"]
        A[Claude]
    end

    subgraph mcp["MCP stdio transport"]
        T[tools/call]
    end

    subgraph core["safe-write-mcp-core"]
        PS[PlanStore]
        AS[ApprovalServer]
    end

    subgraph shopify["Shopify Admin API"]
        GQL[GraphQL endpoint<br/>/admin/api/2026-04/graphql.json]
    end

    subgraph audit["Audit"]
        LF[JSONL audit file<br/>hash-chained]
    end

    A -->|"MCP stdio"| T
    T -->|create plan| PS
    T -->|preview| PS
    T -->|execute plan| PS
    PS -->|awaiting_approval| AS
    AS -->|approve/reject| PS
    PS -->|execute| GQL
    PS -->|record| LF

    style PS fill:#e1f5fe
    style AS fill:#fff3e0
    style LF fill:#f3e5f5
    style GQL fill:#e8f5e9

The two-phase pattern (preview → token → execute) is the core discipline. Every write tool:

1. Preview — reads current state and computes what would change, performing zero mutation calls
2. Token — issues a plan token bound to the exact previewed manifest via a SHA-256 fingerprint
3. Approval — plans exceeding approvalRequiredAboveItems (default 25) or containing always-gated operations wait for human approval at http://127.0.0.1:4319/
4. Execute — re-reads current values, refuses if they drifted from the preview (STATE_CHANGED), then applies mutations per-item with a full success/failure ledger

A plan whose manifest exceeds hardMaxItems (default 250) is refused outright — no token, no approval path.

Irreversible operations (cancel_order, refund_order) always require approval regardless of item count and cannot be rolled back. Reversible operations (price changes, inventory adjustments) support rollback within a configurable window (default 24 hours).

Threat model

The risk is not a malicious agent — the agent is trusted to author correct GraphQL. The risk is a trusted-but-fallible agent: syntactically perfect, well-formed operations whose scope is the problem.

The killer scenario — a syntactically perfect bulk reprice with a misplaced decimal:

update_prices([...], newPrice: 1.5)   ← meant 15.00, typed 1.5

A 500-product bulk update that runs without preview-and-approve, or where the agent's price calculation contains a typo, produces exactly the wrong result at scale. Approval would catch it: a human sees "change 500 prices from $X to $1.50" and flags the不对劲. Without approval, or without the preview that makes the damage visible before it happens, the error lands silently in Shopify.

Three mechanisms carry the safety guarantee:

1. Preview-first, computed-diff. Every write tool reads current state and computes the manifest ({ref, before, after} pairs) without calling any mutation. A STATE_CHANGED re-read at execute time refuses the write if the world moved since preview. The blast radius is visible before anything changes.

2. Approval gating above the threshold. Plans touching >= approvalRequiredAboveItems items (default 25) require human approval. The threshold is sized for "is this large enough to warrant a human eye?" — meaningful for bulk value changes; irrelevant for one-item operations (which get unconditional approval for irreversible ops instead).

3. Plan token bound to exact manifest. The token is a SHA-256 fingerprint of the exact previewed manifest — not an opaque ID. Swapping in a wider set of items or a different price at execute time produces a different fingerprint and is refused as STATEMENT_MISMATCH.

Rollback provides recovery for reversible mistakes (wrong price, wrong inventory level) within the rollback window. It does not recover from the irreversible operations: a cancelled order stays cancelled, a refunded payment stays refunded.

Quick start

npm install
npm test
npm run build

Set the required environment variable and point Claude Desktop at the server (see Configuration below). node dist/index.js starts the localhost approval UI alongside the MCP stdio server.

Configuration

Configuration file (default config.json in the working directory, or path via SHOPIFY_CONFIG):

{
  "shopify": {
    "storeDomain": "my-store.myshopify.com",
    "apiVersion": "2026-04"
  },
  "plans": {
    "planTtlMs": 60000,
    "approvalRequiredAboveItems": 25,
    "hardMaxItems": 250,
    "maxPriceChangePct": 30,
    "rollbackTtlMs": 86400000
  },
  "approvalServer": {
    "enabled": true,
    "port": 4319
  },
  "protectedTags": ["do-not-touch"],
  "callerId": "shopify-operations-mcp"
}

Config reference

Field	Type	Default	Description
shopify.storeDomain	string	(required)	MyShopify domain, e.g. "my-store.myshopify.com"
shopify.apiVersion	string	"2026-04"	Pinned quarterly Admin API version
shopify.adminToken	string	(env only)	Admin API token — never in config file, only SHOPIFY_ADMIN_TOKEN env var
plans.planTtlMs	positive int	60000	How long a plan token stays valid (ms). Overridable: SHOPIFY_PLAN_TTL_MS
plans.approvalRequiredAboveItems	positive int	25	Plans touching this many items require human approval. Overridable: SHOPIFY_APPROVAL_REQUIRED_ABOVE_ITEMS
plans.hardMaxItems	positive int	250	Plans exceeding this item count are refused outright. Overridable: SHOPIFY_HARD_MAX_ITEMS
plans.maxPriceChangePct	positive int	30	Price changes exceeding this % require approval. Overridable: SHOPIFY_MAX_PRICE_CHANGE_PCT
plans.rollbackTtlMs	positive int	86400000	Rollback window (ms, default 24h). Overridable: SHOPIFY_ROLLBACK_TTL_MS
approvalServer.enabled	boolean	true	Start localhost approval UI alongside MCP server. Overridable: SHOPIFY_APPROVAL_SERVER_ENABLED
approvalServer.port	positive int	4319	Port for localhost approval UI (127.0.0.1 only). Overridable: SHOPIFY_APPROVAL_SERVER_PORT
protectedTags	string[]	["do-not-touch"]	Tags that plans may never modify. Overridable: SHOPIFY_PROTECTED_TAGS (comma-separated)
callerId	string	"unknown"	Identity recorded on every audit row. Overridable: SHOPIFY_CALLER_ID

Invariant: plans.hardMaxItems must be >= plans.approvalRequiredAboveItems. The loader throws if violated.

Environment variables

All config fields are overridable by environment variables (precedence: env > config file > default). SHOPIFY_ADMIN_TOKEN is required and only ever read from the environment.

Tools

Read tools

search_products

Search products by title, SKU, vendor, or tag. Returns products with variants, current prices, and per-location inventory levels.

Arguments:

Field	Type	Description
title	string?	Matches products whose title contains the term (Shopify fuzzy search)
sku	string?	Matches products with a variant whose SKU equals the term
vendor	string?	Matches products from this vendor
tag	string?	Matches products carrying this tag
first	positive int?	Page size passed to Admin API (default 50)

Returns: products[] with id, title, vendor, tags, variants (each with id, sku, price, inventoryItemId, inventoryLevels), plus flags.protected / flags.protectedTags indicating whether the product carries a protected tag.

Safety properties: Pure read — zero mutation calls. Protected-tagged products are returned (never filtered out) so a later write plan that touches them is refused.

list_orders

List orders filtered by financial status, fulfillment status, and date range.

Arguments:

Field	Type	Description
financialStatus	FinancialStatus?	"pending" | "authorized" | "partially_paid" | "paid" | "partially_refunded" | "refunded" | "voided"
fulfillmentStatus	FulfillmentStatus?	"fulfilled" | "partial" | "unfulfilled"
createdAfter	ISO-8601 string?	Orders created at or after this datetime
createdBefore	ISO-8601 string?	Orders created at or before this datetime
first	positive int?	Page size (default 250)

Returns: orders[] with id, name, financialStatus, fulfillmentStatus, totalPrice, lineItems[].

Safety properties: Pure read — zero mutation calls.

Write tools (two-phase)

All write tools go through preview → token → (approval) → execute.

update_inventory

Set absolute inventory quantities at a named location for multiple inventory items. Preview reads current levels; execute calls inventorySetQuantities.

Arguments:

Field	Type	Description
locationId	string	gid://shopify/Location/… id
adjustments	InventoryAdjustment[]	Each {inventoryItemId, quantity} sets the available quantity at locationId

Safety properties:

• Threshold gating: requires approval when adjustments.length >= approvalRequiredAboveItems (default 25); refused outright when > hardMaxItems (default 250)
• Protected-tag enforcement: plans touching a product with a protected tag throw PROTECTED_RESOURCE before a token is issued — no approval path
• Per-item ledger: partial failure is recorded, never hidden
• Rollback: supported — restores before.available quantities via the snapshot

cancel_order

Cancel a Shopify order. Always requires approval regardless of item count. Cannot be rolled back.

Arguments:

Field	Type	Description
orderId	string	gid://shopify/Order/… id
reason	string	"customer" | "inventory" | "fraud" | "other"
restock	boolean	Return items to inventory
notifyCustomer	boolean	Send cancellation email

Safety properties:

• Always approval: alwaysRequireApproval: true is hardcoded in the tool — approval thresholds are never consulted
• No snapshot: no snapshotStore.capture() call — rollback is not opened for this operation
• Rollback: refused with ROLLBACK_UNSUPPORTED — cancellation is a state transition, not a value change

refund_order

Refund a Shopify order. Always requires approval regardless of item count. Cannot be rolled back.

Arguments:

Field	Type	Description
orderId	string	gid://shopify/Order/… id
refundLineItems	RefundLineItem[]?	Line items and quantities to refund; absent = full refund of all fulfilled items
reason	string	Human-readable reason recorded in audit

Each RefundLineItem: {lineItemId, quantity, restockType?} where restockType is "RETURN" \| "NO_RESTOCK" \| "CANCEL".

Safety properties:

• Always approval: alwaysRequireApproval: true hardcoded in the tool
• Preview via refundCalculate: zero-write GraphQL call returns exact suggested refund amounts for the approval surface
• No snapshot: no rollback support
• PII-free audit: only order ID and refund amount are recorded; customer name/email are never in the audit trail

rollback_plan

Undo an executed reversible plan within the rollback window (default 24 hours).

Arguments:

Field	Type	Description
planToken	string	The token from the executed plan to roll back

Safety properties:

• No approval required: restoring the prior state is the safe direction
• Window guard: ROLLBACK_WINDOW_EXPIRED when the snapshot has expired or the plan was never previewed
• Kind guard: ROLLBACK_UNSUPPORTED when the plan kind is cancel_order or refund_order
• Inverse mutations only on refs that succeeded at execute time — a ref that failed is left untouched
• Per-item ledger: partial rollback failure is recorded honestly

Plan lifecycle

Agent calls preview tool
       │
       ▼
  Manifest built
  (pure reads, zero writes)
       │
       ▼
  Item count checked
       │
       ├─── <= hardMaxItems ──► token issued
       │                         │
       │                    >= approvalRequiredAboveItems
       │                         │     or alwaysRequireApproval
       │                         ▼
       │              status: "awaiting_approval"
       │                         │
       │                    human approves
       │                         │
       ▼                         │
  HARD_MAX_ITEMS_EXCEEDED         │
  (no token, refused)            ▼
                           execute_plan
                                │
                           STATE_CHANGED check
                           (re-read, compare digest)
                                │
                           ┌────┴────┐
                        success   failure
                           │         │
                      per-item   per-item
                      ledger     ledger
                           │
                      snapshot stored
                      for rollback

Localhost approval UI

A plain-HTML page for a human to approve or reject plans above the threshold. Runs as its own local-only HTTP server, started alongside the MCP server.

• Access: http://127.0.0.1:4319/ (or configured approvalServer.port) on the machine running the server. Unreachable from other machines.
• API: GET /api/plans returns pending plans as JSON; POST /api/plans/:token/approve and POST /api/plans/:token/reject handle approval.
• Security boundary: approval/rejection is never exposed as an MCP tool — the agent cannot approve its own plans.

Audit log

Every preview, approval, execution, rejection, and refusal writes one JSON object to the audit file:

{"seq":1,"prev_hash":"0000...","hash":"ab12...","ts":1734567890000,"tool":"update_inventory","reason":"adjusting stock","planToken":"abc123","status":"executed","previewCount":10,"callerId":"shopify-ops","durationMs":234,"detail":"all 10 item(s) executed"}

• seq — monotonically increasing per-file sequence
• prev_hash — SHA-256 of the previous row (genesis = 64 zero chars)
• hash — SHA-256 of this row (excluding the hash field itself)
• Tamper-evident, not tamper-proof: editing, reordering, or deleting a non-terminal row breaks the chain at that row. Suffix truncation or replacing the whole file with a valid chain is not detectable from the file alone.
• PII defense-in-depth: top-level keys matching /customerEmail|customerName/i are stripped before hashing. Free-text reason/detail strings are not scanned — hosts must sanitize those before calling record().
• Restart safety: on open, the sink verifies the existing chain and resumes seq/prev_hash from the last line.

Verify the chain with scripts/verify-audit.ts.

Limitations

Stated plainly, not hidden:

• Order cancels/refunds are irreversible. Approval protects them — it does not enable rollback. A cancelled order cannot be uncancelled; a refunded payment cannot be unwired. RollbackPlan refuses cancel_order and refund_order tokens with ROLLBACK_UNSUPPORTED.

• Rollback is best-effort snapshot restoration. The snapshot captures the before-state at preview time; it is only usable as an inverse-mutation target while the world hasn't changed. After rollbackTtlMs (default 24h), rollback is refused with ROLLBACK_WINDOW_EXPIRED. Rollback restores values, not external side effects (e.g., a refund notification already sent).

• Partial failure leaves a per-item ledger, not an exception. When a batch mutation fails for some items and succeeds for others, the executor records each outcome honestly. There is no all-or-nothing rollback across items — only per-item inverse mutations at rollback time for the items that succeeded.

• Plan state is in-memory and process-scoped. The PlanStore and SnapshotStore hold all pending and executed plan state in process memory. A server restart loses every pending plan (re-preview required) and every rollback window. The audit log is the durable record of what happened.

• Single store, no multi-tenancy. One server process talks to one Shopify store. Running for multiple stores means running multiple server instances with separate credentials and audit files.

• No per-user auth. callerId identifies the deployment (default "unknown"), not an individual person. There is no per-MCP-session or per-user authentication in v1. Anyone who can reach the server's stdio transport (or 127.0.0.1:4319 for approvals) can use it with the configured store credentials.

• STATE_CHANGED is a pre-write drift check, not a universal compare-and-swap. The re-read catches drift that exists before the mutation is sent. It does not close the window between re-read and write. Shopify exposes provider-level compare-and-swap for some operations (e.g. changeFromQuantity for inventory) but not all (plain price updates are last-write-wins).

License

MIT