> ## Documentation Index > Fetch the complete documentation index at: https://docs.trylath.com/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > Every Lath operation is POST https://platform.trylath.com/, with a JSON body and `Authorization: Bearer `. `email.send` is POST /email/send. > Branch on `error.code`, never on `error.message`. Every refusal also carries `error.fix`, which names the next step. > Send an `Idempotency-Key` header on any operation that is not retry-safe, so a retry cannot run it twice. > A `lath_test_` key emails only the account's own members and sends no SMS; a `lath_live_` key reaches real recipients and is billed. > The OpenAPI document, generated from the same registry as the routes, is at https://platform.trylath.com/openapi.json. # sms.broadcast.send > Sends a draft SMS broadcast: refuses unless the template is published, carries STOP wording and fits in the segment limit, and the topic exists; then queues one message per consenting, unsuppressed contact with a phone number, using the contact's properties as variables. Billing counts real segments, so the whole audience is rendered before anything is queued and the spending cap is checked against the true total. Scheduled broadcasts are queued now and released at the scheduled time. ## OpenAPI ````yaml /api-reference/openapi.json post /sms/broadcast/send openapi: 3.1.0 info: title: Lath API version: 0.1.0 description: >- Every operation is one POST. The same set is reachable over MCP, the SDK and the CLI; nothing is dashboard-only. servers: - url: https://platform.trylath.com description: This deployment security: [] paths: /sms/broadcast/send: post: tags: - sms summary: sms.broadcast.send description: >- Sends a draft SMS broadcast: refuses unless the template is published, carries STOP wording and fits in the segment limit, and the topic exists; then queues one message per consenting, unsuppressed contact with a phone number, using the contact's properties as variables. Billing counts real segments, so the whole audience is rendered before anything is queued and the spending cap is checked against the true total. Scheduled broadcasts are queued now and released at the scheduled time. operationId: sms.broadcast.send parameters: - name: Idempotency-Key in: header required: false schema: type: string description: >- Replays the stored response for the same key and input; refuses different input. requestBody: required: true content: application/json: schema: $schema: https://json-schema.org/draft/2020-12/schema type: object properties: broadcastId: type: string format: uuid pattern: >- ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$ required: - broadcastId additionalProperties: false responses: '200': description: '{ activityId, result }. activityId is empty for reads.' content: application/json: schema: type: object properties: activityId: type: string description: The activity this call created, or empty for a read. result: $schema: https://json-schema.org/draft/2020-12/schema type: object properties: broadcast: type: object properties: id: type: string format: uuid pattern: >- ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$ name: type: string template: type: string topic: type: string segmentId: anyOf: - type: string format: uuid pattern: >- ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$ - type: 'null' variables: {} scheduledAt: anyOf: - type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ - type: 'null' status: type: string enum: - draft - queued - paused - sent - cancelled counts: anyOf: - {} - type: 'null' sentAt: anyOf: - type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ - type: 'null' completedAt: anyOf: - type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ - type: 'null' createdAt: type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ updatedAt: type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ required: - id - name - template - topic - segmentId - variables - scheduledAt - status - counts - sentAt - completedAt - createdAt - updatedAt additionalProperties: {} counts: {} segments: type: integer minimum: -9007199254740991 maximum: 9007199254740991 sendAfter: anyOf: - type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ - type: 'null' required: - broadcast - counts - segments - sendAfter additionalProperties: {} required: - activityId - result '400': description: invalid_input or invalid_json '401': description: unauthenticated '403': description: forbidden '404': description: not_found '409': description: 'conflict: idempotency_mismatch, email_taken, last_key' '413': description: body_too_large '429': description: rate_limited security: - bearer: [] components: securitySchemes: bearer: type: http scheme: bearer description: >- A Lath API key: lath_live_sk… or lath_test_sk… on a server, lath_live_pk… or lath_test_pk… in a browser. ````