# Arm a jurisdiction > The registrations.arm operation: POST /api/v1/registrations/{id}/arm in the REST API and the registrations_arm tool in the MCP server. Arms a blocked jurisdiction: you confirm that its registration prerequisites are complete and that someone will register within the regime's grace period. It stays `blocked_b2c` with `armed: true`, and the first consumer sale there starts the grace period and its deadline (spec §10.2). Use it for regimes with no threshold that allow registering shortly after the first sale (EU non-Union OSS, the UK). Needs `blocked_b2c` (not armed), every prerequisite `done` and a regime with a grace period; an obligation already triggered whose grace period has passed can't be armed (register and mark it registered instead). Compliance tier (spec §41.4): tax managers, owners and admins. If the organization's approval policy lists this operation, the call answers `approval_required` and runs once a second person approves it. Dry-run it first (`Ownrecord-Dry-Run: true`, `dry_run: true`) to see the result. Returns the registration. ## At a glance - **REST:** `POST /api/v1/registrations/{id}/arm` - **MCP tool:** `registrations_arm` - **Operation ID:** `registrations.arm` - **Scope:** Legal entity - **Permission:** `registrations:write` - **Risk tier:** `compliance` - **Dry run:** Supported (send `Ownrecord-Dry-Run: true`) - **Idempotency:** `Idempotency-Key` required - **Modes:** Test and live - **Authentication:** API key with the `registrations:write` scope - **Since:** M3 ## Request ### Path parameters | Field | Type | Description | | ----- | ------ | ----------------------------------------------------------------------------------------- | | `id` | string | The registration (`regn_…`) or its regime's ID, e.g. `EU_OSS_UNION` or `US_SALES_TAX:TX`. | ### Body A JSON object (`Content-Type: application/json`): | Field | Type | Required | Description | | ------ | ------ | -------- | -------------------------------------------------------------------------------------------- | | `note` | string | No | Why, or anything the team should know; kept in the registration's history and the audit log. | ## Response `200 OK` with a JSON object: | Field | Type | Description | | ------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------- | ----------- | | `id` | `regn_…` ID | | | `object` | `"registration"` | | | `entityId` | `ent_…` ID | | | `livemode` | boolean | | | `regimeId` | string | | | `regimeName` | string or null | | | `jurisdictionIds` | array of string | | | `state` | one of `not_applicable`, `monitored`, `pre_registration`, `grace`, `registered`, `blocked_b2c`, `deregistered` | | | `stateReason` | one of 18 values, e.g. `home_country`, `below_threshold`, `zero_threshold` (all in the OpenAPI document) | | | `stateChangedAt` | date-time | | | `armed` | boolean | | | `triggeredAt` | date-time or null | | | `deadlineAt` | date-time or null | | | `autoBlockAt` | date-time or null | | | `applicationSubmittedAt` | date-time or null | | | `escalationLevel` | integer (0 to 3) | | | `registrationNumber` | string or null | | | `effectiveFrom` | date-time or null | | | `registeredAt` | date-time or null | | | `prerequisitesDone` | boolean | | | `prerequisitesProgress` | object | | | `prerequisitesProgress.done` | integer | | | `prerequisitesProgress.total` | integer | | | `threshold` | object or null | | | `timeZones` | array of string | | | `createdAt` | date-time | | | `updatedAt` | date-time | | | `prerequisites` | array of object | | | `prerequisites[].code` | string | | | `prerequisites[].description` | string or null | | | `prerequisites[].leadTimeDays` | integer or null | | | `prerequisites[].status` | one of `todo`, `in_progress`, `done` | | | `prerequisites[].doneAt` | date-time or null | | | `prerequisites[].notes` | string | | | `prerequisites[].owner` | string or null | | | `prerequisites[].attachments` | array of object | | | `prerequisites[].attachments[].kind` | one of `file`, `reference` | | | `prerequisites[].attachments[].ref` | string | | | `prerequisites[].attachments[].label` | string or null | | | `prerequisites[].attachments[].addedAt` | date-time | | | `prerequisites[].attachments[].addedBy` | string | | | `prerequisites[].updatedAt` | date-time or null | | | `prerequisites[].updatedBy` | string or null | | | `evidenceFiles` | array of object | | | `evidenceFiles[].kind` | one of `file`, `reference` | | | `evidenceFiles[].ref` | string | | | `evidenceFiles[].label` | string or null | | | `evidenceFiles[].addedAt` | date-time | | | `evidenceFiles[].addedBy` | string | | | `history` | array of object | | | `history[].from` | one of `not_applicable`, `monitored`, `pre_registration`, `grace`, `registered`, `blocked_b2c`, `deregistered` or null | | | `history[].to` | one of `not_applicable`, `monitored`, `pre_registration`, `grace`, `registered`, `blocked_b2c`, `deregistered` | | | `history[].at` | date-time | | | `history[].by` | string | | | `history[].reason` | one of 18 values, e.g. `home_country`, `below_threshold`, `zero_threshold` (all in the OpenAPI document) | | | `history[].note` | string or null | | | `counters` | array of object | | | `counters[].windowKey` | string | | | `counters[].amount` | money | | | `counters[].transactionCount` | integer | | | `counters[].lastEventAt` | date-time | | | `regime` | object or null | | | `playbooks` | array of object | | | `playbooks[].key` | string | | | `playbooks[].kind` | one of `registration`, `filing`, `deregistration`, `other` | | | `playbooks[].markdown` | string | | | `officialLinks` | array of object | | | `officialLinks[].label` | string | | | `officialLinks[].url` | string | | | `actions` | object | | | `actions.arm` | object | | | `actions.arm.allowed` | boolean | | | `actions.arm.code` | string or null | | | `actions.arm.message` | string or null | | | `actions.markApplicationSubmitted` | object | | | `actions.markApplicationSubmitted.allowed` | boolean | | | `actions.markApplicationSubmitted.code` | string or null | | | `actions.markApplicationSubmitted.message` | string or null | | | `actions.markRegistered` | object | | | `actions.markRegistered.allowed` | boolean | | | `actions.markRegistered.code` | string or null | | | `actions.markRegistered.message` | string or null | | | `actions.deregister` | object | | | `actions.deregister.allowed` | boolean | | | `actions.deregister.code` | string or null | | | `actions.deregister.message` | string or null | | | `safetyBufferHours` | integer | | | `knowledgeCommit` | string | | ## Examples ### Arm EU non-Union OSS ```http POST /api/v1/registrations/EU_OSS_NON_UNION/arm Authorization: Bearer or_test_… Idempotency-Key: 3f1c9a52-7d0e-4b8f-9a61-0c2d5e8b7f14 Content-Type: application/json { "note": "OSS portal access ready; Ana files within the month" } ``` Response (`200`): ```json { "id": "regn_01m4tx5nj8emwbyf7y9vcf47xk", "object": "registration", "entityId": "ent_01m4tx5nj8emwbyf7y9vcf47x2", "livemode": true, "regimeId": "EU_OSS_NON_UNION", "regimeName": "EU One-Stop Shop, non-Union scheme", "jurisdictionIds": ["AT", "DE", "FR", "HR", "IT", "NL"], "state": "blocked_b2c", "stateReason": "armed", "stateChangedAt": "2026-10-13T12:00:00.000Z", "armed": true, "triggeredAt": null, "deadlineAt": null, "autoBlockAt": null, "applicationSubmittedAt": null, "escalationLevel": 0, "registrationNumber": null, "effectiveFrom": null, "registeredAt": null, "prerequisitesDone": true, "prerequisitesProgress": { "done": 1, "total": 1 }, "threshold": null, "timeZones": ["Europe/Zagreb"], "createdAt": "2026-10-13T12:00:00.000Z", "updatedAt": "2026-10-13T12:00:00.000Z", "prerequisites": [ { "code": "portal_access", "description": "Access to the tax portal of the member state of identification", "leadTimeDays": 7, "status": "done", "doneAt": "2026-10-13T12:00:00.000Z", "notes": "ePorezna access for the finance team", "owner": "Ana (finance)", "attachments": [], "updatedAt": "2026-10-13T12:00:00.000Z", "updatedBy": "usr_01m4tx5nj8emwbyf7y9vcf47xa" } ], "evidenceFiles": [], "history": [ { "from": null, "to": "monitored", "at": "2026-10-13T12:00:00.000Z", "by": "system", "reason": "below_threshold", "note": null }, { "from": "monitored", "to": "pre_registration", "at": "2026-10-13T12:00:00.000Z", "by": "system", "reason": "pre_registration_ratio_reached", "note": null } ], "counters": [ { "windowKey": "2026", "amount": { "amount": "8500000000", "currency": "EUR" }, "transactionCount": 412, "lastEventAt": "2026-10-13T12:00:00.000Z" } ], "regime": { "id": "EU_OSS_UNION", "name": "EU One-Stop Shop, Union scheme", "version": "3f2a9c41d07e88b1", "jurisdictionIds": ["AT", "DE", "FR", "HR", "IT", "NL"], "sellerEstablishment": "in_eu_other_ms", "customerType": "b2c", "threshold": { "amount": { "amount": "10000000000", "currency": "EUR" }, "measure": "eu_cross_border_b2c", "window": "calendar_year_current_or_previous", "transactionCount": null, "whatCounts": "B2C electronically supplied services to consumers in other member states, net of VAT.", "amountInclusive": false }, "zeroThreshold": false, "grace": { "rule": "nth_day_of_following_month", "days": null, "nthDay": 10 }, "collectBeforeRegistration": true, "b2bReverseChargeNoRegistration": true, "b2bChargeWhenRegistered": false, "requiresFiscalRepresentative": false, "requiresLocalAgent": false, "securityDeposit": null, "registration": { "method": "online", "portalUrl": "https://e-porezna.porezna-uprava.hr", "identityRequirements": null, "typicalProcessingDays": 7 }, "status": "verified", "unverified": false, "fixture": false, "validFrom": "2021-07-01", "validTo": null }, "playbooks": [ { "key": "EU/playbooks/EU_OSS_UNION-registration.md", "kind": "registration", "markdown": "# Registering for the Union OSS\n\n1. Sign in to the portal of your member state …" } ], "officialLinks": [ { "label": "EU One-Stop Shop, Union scheme: registration portal", "url": "https://e-porezna.porezna-uprava.hr" } ], "actions": { "arm": { "allowed": false, "code": "registration_transition_invalid", "message": "EU_OSS_UNION is pre_registration, so \"arm\" isn't possible." }, "markApplicationSubmitted": { "allowed": false, "code": "registration_transition_invalid", "message": "EU_OSS_UNION is pre_registration, so \"application_submitted\" isn't possible." }, "markRegistered": { "allowed": true, "code": null, "message": null }, "deregister": { "allowed": false, "code": "registration_transition_invalid", "message": "EU_OSS_UNION is pre_registration, so \"deregister\" isn't possible." } }, "safetyBufferHours": 72, "knowledgeCommit": "1c14b2ec912aca347dd518b2044096f3b5d8eef1" } ``` ## Errors | Code | HTTP status | When | What to do | | ------------------------------------------------------------------------------------------------------------------------------ | ----------- | ---------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [`registration_transition_invalid`](https://ownrecord.io/docs/reference/errors.md#registration_transition_invalid) | 409 | The registration isn't `blocked_b2c`, or it is armed already (`details.allowed_from`). | Check the registration's state (`details.state`): `details.allowed_from` lists the states the action needs. Reload the registration and try the action that fits its state. | | [`registration_prerequisites_incomplete`](https://ownrecord.io/docs/reference/errors.md#registration_prerequisites_incomplete) | 409 | A prerequisite isn't `done` yet. | Finish the prerequisites on the registration page (portal access, fiscal representative, documents …), mark each one done, then arm again. | | [`registration_grace_not_allowed`](https://ownrecord.io/docs/reference/errors.md#registration_grace_not_allowed) | 409 | The regime has no grace period (e.g. US states). | Register with the tax authority first, then mark the registration registered with its number, effective date and proof. | | [`registration_grace_expired`](https://ownrecord.io/docs/reference/errors.md#registration_grace_expired) | 409 | An obligation already triggered and its grace period has passed. | Complete the registration with the tax authority and mark it registered with its number, effective date and proof. | | [`validation_failed`](https://ownrecord.io/docs/reference/errors.md#validation_failed) | 400 | A field is missing or malformed (`details.issues`). | Fix the fields listed in `details.issues` and send the request again. | | [`resource_not_found`](https://ownrecord.io/docs/reference/errors.md#resource_not_found) | 404 | This entity has no such registration in this mode. | Check the ID and that your credentials are scoped to the right organization, entity, brand and mode. | | [`jurisdiction_blocked`](https://ownrecord.io/docs/reference/errors.md#jurisdiction_blocked) | 422 | The tax knowledge no longer has a usable regime for this registration, so it can't change now. | This jurisdiction isn't covered by usable tax knowledge for this seller. Contact support if you need to sell there. | | [`approval_required`](https://ownrecord.io/docs/reference/errors.md#approval_required) | 202 | The organization's approval policy needs a second person for this action; nothing changed yet. | Nothing ran yet. An approver reviews `approval.summary` and the dry-run result in the console (`approval.approveUrl`). Poll `GET /approvals/{id}` or watch for the `approval.resolved` event; sending the same request again with the same Idempotency-Key returns the same approval. | | [`approval_rejected`](https://ownrecord.io/docs/reference/errors.md#approval_rejected) | 409 | The same request was sent again after it was rejected. | Read the reason in `details.approval.rejection`. To try again, send a new request with a new Idempotency-Key. | | [`approval_expired`](https://ownrecord.io/docs/reference/errors.md#approval_expired) | 409 | The same request was sent again after its approval request expired. | Send the request again with a new Idempotency-Key to create a new approval request. Requests expire after 72 hours. | | [`stale_approval`](https://ownrecord.io/docs/reference/errors.md#stale_approval) | 409 | The approved request could no longer run as requested. | Check the current state (`details.approval.failure` says what failed), then send a new request with a new Idempotency-Key. | | [`idempotency_key_reused`](https://ownrecord.io/docs/reference/errors.md#idempotency_key_reused) | 409 | The idempotency key was used before with another input. | Use a new Idempotency-Key for a different request, or resend the original request unchanged. | | [`livemode_not_allowed`](https://ownrecord.io/docs/reference/errors.md#livemode_not_allowed) | 403 | You have no live-mode access, so you can't change live registrations. | Use test mode, or credentials for the target's mode. Developers need live access granted by an organization owner or admin. | | [`scope_required`](https://ownrecord.io/docs/reference/errors.md#scope_required) | 400 | The request names no legal entity (an org key without `Ownrecord-Entity`). | Call the operation with credentials or a target at its level: an organization, a legal entity, a brand or the platform (`details.required_scope`). | | [`permission_denied`](https://ownrecord.io/docs/reference/errors.md#permission_denied) | 403 | You can't change this entity's registrations (tax managers, owners and admins can). | Ask an organization owner or admin for a role or scope that allows this action. | | [`version_conflict`](https://ownrecord.io/docs/reference/errors.md#version_conflict) | 409 | The registration changed at the same moment (a sale or the deadline job); reload and retry. | Fetch the object again and retry the change. | It can also return these [common errors](https://ownrecord.io/docs/reference.md#common-errors): [`api_version_unsupported`](https://ownrecord.io/docs/reference/errors.md#api_version_unsupported), [`invalid_json`](https://ownrecord.io/docs/reference/errors.md#invalid_json), [`unsupported_media_type`](https://ownrecord.io/docs/reference/errors.md#unsupported_media_type), [`authentication_required`](https://ownrecord.io/docs/reference/errors.md#authentication_required), [`api_key_invalid`](https://ownrecord.io/docs/reference/errors.md#api_key_invalid), [`idempotency_key_required`](https://ownrecord.io/docs/reference/errors.md#idempotency_key_required), [`idempotency_in_progress`](https://ownrecord.io/docs/reference/errors.md#idempotency_in_progress), [`approval_policy_denied`](https://ownrecord.io/docs/reference/errors.md#approval_policy_denied), [`rate_limited`](https://ownrecord.io/docs/reference/errors.md#rate_limited), [`internal_error`](https://ownrecord.io/docs/reference/errors.md#internal_error).