> ## Documentation Index > Fetch the complete documentation index at: https://docs.arcuserp.com/llms.txt > Use this file to discover all available pages before exploring further. # Update a fixed-asset category > Updates editable fields on a category. System-seeded categories (`is_system: true`) cannot be edited and return SYSTEM_CATEGORY_LOCKED. Editable fields: name, default_useful_life_months, default_depreciation_method, default_macrs_class, and the three default GL account routings. Requires the `assets:write` scope. ## OpenAPI ````yaml /openapi.yaml patch /fixed_asset_categories/{id} openapi: 3.1.0 info: title: Arcus ERP Public API version: 1.0.0 description: > Arcus ERP public REST API. Designed for external integrations and data migration. **Authentication.** Bearer token (API key) via the `Authorization` header. Format: `Authorization: Bearer ark_live_ent__` (or `ark_test_*` for sandbox). API keys are issued per-entity in **Settings > Developers > API Keys**. **Entity scoping.** The entity is encoded in the API key prefix; routes are flat (e.g. `/v1/accounts`, `/v1/orders`, `/v1/products`). A small set of platform endpoints (migration, reconciliation, events, webhook endpoints, API keys) use the `/v1/entities/{entity_id}/...` form -- those are noted in their tags. **Key capabilities.** - Related-resource hydration via `?expand[]=` (see `x-arcus-expand` on each resource). - Cursor-based pagination (`starting_after` / `ending_before` / `limit`). - Idempotency via the `Idempotency-Key` header. - Webhook events for asynchronous notification. - Conditional requests / ETag for cache validation. servers: - url: https://api.arcuserp.com/v1 description: Arcus ERP API (accepts both live `ark_live_*` and test `ark_test_*` keys) - url: https://dev-api.arcuserp.com/v1 description: >- Dev sandbox API (test-only data, accepts `ark_test_*` keys against dev RDS) security: [] paths: /fixed_asset_categories/{id}: parameters: - name: id in: path required: true schema: type: string format: uuid patch: tags: - Fixed Assets summary: Update a fixed-asset category description: | Updates editable fields on a category. System-seeded categories (`is_system: true`) cannot be edited and return SYSTEM_CATEGORY_LOCKED. Editable fields: name, default_useful_life_months, default_depreciation_method, default_macrs_class, and the three default GL account routings. Requires the `assets:write` scope. operationId: updateAssetCategory requestBody: required: true content: application/json: schema: type: object properties: name: type: string default_useful_life_months: type: integer default_depreciation_method: type: string enum: - straight_line - declining_balance - double_declining - sum_of_years - units_of_production - macrs - bonus_macrs - section_179 default_macrs_class: type: string enum: - three_year - five_year - seven_year - ten_year - fifteen_year - twenty_year - twenty_seven_five_year - thirty_nine_year default_gl_asset_account_id: type: string format: uuid default_gl_accum_depr_account_id: type: string format: uuid default_gl_depr_expense_account_id: type: string format: uuid responses: '200': description: Updated category content: application/json: schema: type: object properties: data: $ref: '#/components/schemas/FixedAssetCategory' '400': description: SYSTEM_CATEGORY_LOCKED or INVALID_INPUT content: application/json: schema: $ref: '#/components/schemas/Error' '404': $ref: '#/components/responses/Error' security: - ApiKeyAuth: - assets:write components: schemas: FixedAssetCategory: type: object description: > A fixed-asset category (Buildings, Machinery, Vehicles, Computer Equipment, etc.). Categories may carry default depreciation method + useful-life + MACRS class + GL account routing; assets created with a `category_id` inherit those defaults automatically. System-seeded categories carry `is_system: true` and cannot be edited or deleted. Scope: assets:read / assets:write / assets:delete. properties: id: type: string format: uuid readOnly: true entity_id: type: string format: uuid readOnly: true slug: type: string description: Stable machine-readable identifier (unique per entity). name: type: string default_useful_life_months: type: integer nullable: true default_depreciation_method: type: string nullable: true enum: - straight_line - declining_balance - double_declining - sum_of_years - units_of_production - macrs - bonus_macrs - section_179 default_macrs_class: type: string nullable: true enum: - three_year - five_year - seven_year - ten_year - fifteen_year - twenty_year - twenty_seven_five_year - thirty_nine_year default_gl_asset_account_id: type: string format: uuid nullable: true default_gl_accum_depr_account_id: type: string format: uuid nullable: true default_gl_depr_expense_account_id: type: string format: uuid nullable: true sort_order: type: integer nullable: true is_system: type: boolean readOnly: true created_at: type: string format: date-time readOnly: true updated_at: type: string format: date-time readOnly: true Error: description: | Alias for ErrorEnvelope. Canonical error response shape used by all API endpoints. Refer to ErrorEnvelope for the full field definition. allOf: - $ref: '#/components/schemas/ErrorEnvelope' ErrorEnvelope: type: object description: | Canonical error response envelope. All API errors use this shape. required: - error - code properties: error: type: string description: Machine-readable error key example: not_found code: type: string description: Machine-readable error code (often same as error) example: not_found type: type: string enum: - validation_error - permission_error - not_found - conflict - rate_limit - internal - expand_error - not_implemented example: not_found hint: type: string description: Human-readable one-sentence explanation (English) example: >- The requested order does not exist or does not belong to this entity. param: type: string description: The parameter that caused the error, if applicable example: expand[0] required: type: string description: The scope required (only on insufficient_scope errors) example: accounts:read request_id: type: string description: >- Unique request ID for support tracing (maps to CloudWatch log stream) example: req_abc123 responses: Error: description: Error response (400/401/403/404/409/422/429/500) content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' securitySchemes: ApiKeyAuth: type: http scheme: bearer description: | API key issued per entity via Settings > Developers > API Keys. Each key carries scopes (e.g. orders:read, products:write). Bearer token format: Authorization: Bearer ark_live_ent__ Test keys use ark_test_ent__. Both are issued per entity via Settings > Developers > API Keys. ````