> ## Documentation Index > Fetch the complete documentation index at: https://docs.gtm-api.com/llms.txt > Use this file to discover all available pages before exploring further. # Purchase credits > Top up credits. Creates a Paddle one-time transaction and returns a checkout_url for the human to pay; the credits land AFTER transaction.completed (ASYNC: poll get_credit_balance or await the webhook). CREDITABLE + DESTRUCTIVE: charges the owner's card / opens Paddle checkout; the real gate is the human confirming the amount in the Paddle overlay. On retry the agent MUST reuse the SAME request_id; a fresh key creates a second charge. Contract: - MCP tool `purchase_credits`, registry package `mcp.id/credit_transactions`, mount `id.credits`. - Operation `action`, response envelope `action_async`. - Flags: dangerous: the MCP layer gates it behind a preview/commit token, and the effect cannot be undone through this API; creditable: the response carries a `credits` block and the call can debit the team ledger. ## OpenAPI ````yaml /api-reference/id/openapi.yaml post /api/credit-transactions/purchase openapi: 3.0.3 info: title: 'GTM API public contract: gtm.service.id' description: >- Identity, access and money: users, teams and members, API keys, OAuth clients and authorizations, billing products, subscriptions, transactions and payment methods, the credit ledger, notifications, TLS certificates, observability and support requests. GENERATED. This document is projected from the Zod MCP tool registry in `product/mcp/gtm.mcp` (one tool per public endpoint, 1:1). Do not edit it by hand; edit the tool definition and regenerate with `pnpm openapi:public`. Surface: the public `/api` contract of `gtm.service.id`, 77 operations. Internal (`/internal`) and health endpoints are deliberately absent; the code-faithful spec that documents those lives in `product/openapi/gtm.openapi.tech`. Conventions: - Auth is a bearer JWT, optionally narrowed by the `Team-SID` header. - Every success body is an MCP envelope: `success: true` plus one typed `operation` shape (`search`, `get`, `create`, `update`, `delete`, `metrics`, `group_by`, `action`), and a `meta` block with `trace_id` for support. - Every failure is the same `McpError` envelope with a code from a fixed 16-code taxonomy, so a client maps errors once. - Lists page with `page_size` (0 to 500, default 50) plus an opaque forward `cursor`; `page_size: 0` returns counts only. - On `GET` and `DELETE`, object-valued query parameters (`filter`, `sort`) travel as JSON text and array-valued ones repeat as `name[]=value`. - The MCP-only `_meta` field (usage analytics) never reaches the backend and is not part of this contract. version: '1.0' contact: name: GTM API url: https://gtm-api.com email: support@gtm-api.com license: name: Proprietary url: https://gtm-api.com/license servers: - url: https://app.gtm-api.com/id/v4 description: Production, through the app.gtm-api.com gateway - url: http://localhost:8021 description: Local Docker (gtm_id_nginx_dev) security: - BearerJwt: [] TeamSid: [] tags: - name: account_shares description: Registry package `mcp.id/account_shares`, served on MCP mount `id.access`. - name: api_keys description: Registry package `mcp.id/api_keys`, served on MCP mount `id.access`. - name: billing_payment_methods description: >- Registry package `mcp.id/billing_payment_methods`, served on MCP mount `id.billing`. - name: billing_products description: >- Registry package `mcp.id/billing_products`, served on MCP mount `id.billing`. - name: billing_subscriptions description: >- Registry package `mcp.id/billing_subscriptions`, served on MCP mount `id.billing`. - name: billing_transactions description: >- Registry package `mcp.id/billing_transactions`, served on MCP mount `id.billing`. - name: credit_transactions description: >- Registry package `mcp.id/credit_transactions`, served on MCP mount `id.credits`. - name: notifications description: >- Registry package `mcp.id/notifications`, served on MCP mount `id.platform`. - name: oauth_authorizations description: >- Registry package `mcp.id/oauth_authorizations`, served on MCP mount `id.access`. - name: oauth_clients description: Registry package `mcp.id/oauth_clients`, served on MCP mount `id.access`. - name: observability_requests description: >- Registry package `mcp.id/observability_requests`, served on MCP mount `id.platform`. - name: sessions description: Registry package `mcp.id/sessions`, served on MCP mount `id.identity`. - name: ssl_certificates description: >- Registry package `mcp.id/ssl_certificates`, served on MCP mount `id.platform`. - name: support_requests description: >- Registry package `mcp.id/support_requests`, served on MCP mount `id.platform`. - name: team_members description: Registry package `mcp.id/team_members`, served on MCP mount `id.identity`. - name: teams description: Registry package `mcp.id/teams`, served on MCP mount `id.identity`. - name: users description: Registry package `mcp.id/users`, served on MCP mount `id.identity`. paths: /api/credit-transactions/purchase: post: tags: - credit_transactions summary: Purchase credits description: >- Top up credits. Creates a Paddle one-time transaction and returns a checkout_url for the human to pay; the credits land AFTER transaction.completed (ASYNC: poll get_credit_balance or await the webhook). CREDITABLE + DESTRUCTIVE: charges the owner's card / opens Paddle checkout; the real gate is the human confirming the amount in the Paddle overlay. On retry the agent MUST reuse the SAME request_id; a fresh key creates a second charge. Contract: - MCP tool `purchase_credits`, registry package `mcp.id/credit_transactions`, mount `id.credits`. - Operation `action`, response envelope `action_async`. - Flags: dangerous: the MCP layer gates it behind a preview/commit token, and the effect cannot be undone through this API; creditable: the response carries a `credits` block and the call can debit the team ledger. operationId: purchase_credits requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/PurchaseCreditsRequest' responses: '200': description: '`action_async` success envelope.' content: application/json: schema: $ref: '#/components/schemas/PurchaseCreditsResponse' 4XX: $ref: '#/components/responses/McpClientError' 5XX: $ref: '#/components/responses/McpServerError' components: schemas: PurchaseCreditsRequest: type: object description: Request body of `purchase_credits`. properties: kind: type: string enum: - enrichment description: 'Consumable family: MVP "enrichment".' amount: type: integer minimum: 1 description: Credits to buy. request_id: type: string maxLength: 64 description: >- Idempotency key; MUST be stable across retries. A new key = a second charge. required: - kind - amount - request_id PurchaseCreditsResponse: type: object properties: success: type: boolean enum: - true operation: type: string enum: - action action: type: string async: type: boolean enum: - true item: type: object nullable: true properties: sid: type: string team_sid: type: string kind: type: string enum: - enrichment type: type: string enum: - allocation - debit - refund - expiry status: type: string enum: - pending - confirmed - released - expired amount: type: number operation: type: string nullable: true reference_sid: type: string nullable: true request_id: type: string nullable: true expires_at: type: string nullable: true metadata: type: object nullable: true properties: account_sid: type: string nullable: true lot_breakdown: type: array nullable: true items: type: object properties: lot_sid: type: string amount: type: number required: - lot_sid - amount purchase: type: boolean nullable: true required: - account_sid - lot_breakdown - purchase confirmed_at: type: string nullable: true released_at: type: string nullable: true created_at: type: string updated_at: type: string required: - sid - team_sid - kind - type - status - amount - operation - reference_sid - request_id - expires_at - metadata - confirmed_at - released_at - created_at - updated_at pending: type: array items: type: object properties: activity_log_sid: type: string expected_completion_seconds: type: integer minimum: 0 webhook_events: type: array items: type: string required: - expected_completion_seconds - webhook_events result: type: object additionalProperties: {} meta: type: object properties: trace_id: type: string description: UUID v7; same 128-bit value as the X-Trace-Id header. span_id: type: string pattern: ^[0-9a-f]{16}$ description: 16 hex chars, root span of this request. timestamp: type: string description: ISO 8601 UTC (Y-m-dTH:i:sZ), response time. duration_ms: type: integer minimum: 0 description: Server-side wall clock. debug_url: type: string description: Deep link to the post-call analysis UI. required: - trace_id - span_id - timestamp - duration_ms - debug_url credits: type: object properties: charged: type: integer minimum: 0 description: Credits debited for THIS call (0 on own-account / cache hit). reason: type: string nullable: true enum: - infra_pool - limit_fallback executed_on: type: string enum: - own_account - infra_pool balance_after: type: integer nullable: true minimum: 0 description: >- Team balance after the debit; null when the ledger was untouched. required: - charged - reason - executed_on - balance_after required: - success - operation - action - async - item - pending - result - meta McpError: type: object properties: success: type: boolean enum: - false error: type: object properties: code: type: string enum: - validation_failed - nothing_to_update - not_found - relation_not_found - invalid_transition - limit_exceeded - payment_required - duplicate_rejected - conflict - delete_blocked - unauthorized - forbidden - rate_limited - internal_error - service_unavailable - not_implemented message: type: string recoverable: type: boolean suggestion: type: string field_errors: type: object additionalProperties: type: array items: anyOf: - type: string - type: object properties: rule: type: string message: type: string required: - rule - message blockers: type: array items: type: object properties: type: type: string description: >- Machine-readable blocker type (active_flow, pending_tasks, …). severity: type: string enum: - hard - soft description: >- hard = external action required; soft = acknowledge is enough. description: type: string entity_sid: type: string nullable: true count: type: integer resolution: type: string description: 'Hard: tool name to call. Soft: code for acknowledge[].' resolution_hint: type: string required: - type - severity - description - entity_sid - resolution - resolution_hint context: type: object additionalProperties: {} required: - code - message - recoverable meta: type: object properties: trace_id: type: string description: UUID v7; same 128-bit value as the X-Trace-Id header. span_id: type: string pattern: ^[0-9a-f]{16}$ description: 16 hex chars, root span of this request. timestamp: type: string description: ISO 8601 UTC (Y-m-dTH:i:sZ), response time. duration_ms: type: integer minimum: 0 description: Server-side wall clock. debug_url: type: string description: Deep link to the post-call analysis UI. required: - trace_id - span_id - timestamp - duration_ms - debug_url required: - success - error responses: McpClientError: description: >- MCP error envelope. `error.code` is one of validation_failed, nothing_to_update, not_found, relation_not_found, invalid_transition, limit_exceeded, payment_required, duplicate_rejected, conflict, delete_blocked, unauthorized, forbidden, rate_limited, not_implemented. content: application/json: schema: $ref: '#/components/schemas/McpError' McpServerError: description: >- MCP error envelope with `error.code` internal_error or service_unavailable. content: application/json: schema: $ref: '#/components/schemas/McpError' securitySchemes: BearerJwt: type: http scheme: bearer bearerFormat: JWT description: >- Access token issued by gtm.service.id. Its `access_identity` claim carries `team_sid`, `actor_sid` and `actor_type`, and that team scope is authoritative. TeamSid: type: apiKey in: header name: Team-SID description: >- Team scope for tokens that do not carry one. Ignored when the token already names a team. ````