> ## 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.send > Sends one SMS to one number in E.164 form, from the environment's configured sender. The body may carry {{variables}}. Asks the audience policy first: a number that has replied STOP is recorded as suppressed, not sent. Billing counts segments, not messages — a body outside the GSM alphabet costs more than twice as much per character, and the reply says how many segments were counted. If the environment cannot text anyone yet (no active carrier registration, or no number to send from) the message is still stored and the reply carries `blocked` saying why — do not wait on a status that cannot change until that clears. ## OpenAPI ````yaml /api-reference/openapi.json post /sms/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/send: post: tags: - sms summary: sms.send description: >- Sends one SMS to one number in E.164 form, from the environment's configured sender. The body may carry {{variables}}. Asks the audience policy first: a number that has replied STOP is recorded as suppressed, not sent. Billing counts segments, not messages — a body outside the GSM alphabet costs more than twice as much per character, and the reply says how many segments were counted. If the environment cannot text anyone yet (no active carrier registration, or no number to send from) the message is still stored and the reply carries `blocked` saying why — do not wait on a status that cannot change until that clears. operationId: sms.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: $schema: https://json-schema.org/draft/2020-12/schema type: object properties: to: type: string pattern: ^\+[1-9]\d{6,14}$ description: One recipient, E.164, e.g. +14155550100 template: description: >- An SMS template name; provide variables with it. Use instead of body, not with it. type: string minLength: 1 maxLength: 120 locale: description: >- Send the template's variant for this language, falling back to the broader language and then the default. Omit to use the recipient's own locale if one is recorded. type: string maxLength: 20 body: description: 'Inline send: the message; may reference {{variables}}' type: string minLength: 1 maxLength: 1600 variables: type: object propertyNames: type: string pattern: ^[A-Za-z_][A-Za-z0-9_]*$ additionalProperties: {} sendAfter: description: >- Hold the message until this moment; omit to send now. Until it is sent it can be stopped with sms.message.cancel. 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)))$ topic: description: >- A consent topic for marketing; omit for transactional, which only a suppression stops type: string minLength: 1 maxLength: 64 metadata: description: >- Up to 20 key/values echoed on every webhook about this message type: object propertyNames: type: string maxLength: 40 additionalProperties: anyOf: - type: string maxLength: 500 - type: number - type: boolean required: - to 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: $schema: https://json-schema.org/draft/2020-12/schema type: object properties: messageId: type: string format: uuid pattern: >- ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$ status: type: string enum: - queued - suppressed to: type: string segments: type: integer minimum: -9007199254740991 maximum: 9007199254740991 encoding: type: string template: type: - string - 'null' templateVersion: anyOf: - type: integer minimum: -9007199254740991 maximum: 9007199254740991 - type: 'null' templateLocale: type: - string - 'null' 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' suppressed: type: object properties: reason: type: string detail: type: string required: - reason - detail additionalProperties: {} blocked: type: object properties: reason: type: string fix: type: string required: - reason - fix additionalProperties: {} required: - messageId - status - to - segments - encoding - template - templateVersion - templateLocale - 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. ````