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OpenAPI Specification
openapi: 3.2.0
info:
title: SLNG Voice Agents Calls API
version: 1.0.0
description: 'Public API for managing Voice Agents, dispatching outbound calls, and creating web (non-telephony) sessions.
Base URL: `https://api.agents.slng.ai`'
contact:
name: SLNG Support
email: support@slng.ai
servers:
- url: https://api.agents.slng.ai
description: Production
security:
- bearerAuth: []
tags:
- name: Calls
description: Call dispatch and status.
paths:
/v1/agents/{agent_id}/calls:
parameters:
- $ref: '#/components/parameters/AgentIdPath'
post:
operationId: dispatchCall
summary: Dispatch call
description: 'Dispatch an outbound call for a voice agent.
Note: outbound calls require the agent to be configured with an outbound connection.'
tags:
- Calls
requestBody:
required: true
content:
application/json:
schema:
$ref: '#/components/schemas/AgentCallCreate'
responses:
'200':
description: Call dispatched.
content:
application/json:
schema:
$ref: '#/components/schemas/AgentCallResponse'
'400':
description: Bad request.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
examples:
outbound-telephony-not-configured:
summary: Agent is missing an outbound connection
value:
detail: Outbound telephony is not configured for this agent (missing outbound connection).
'401':
$ref: '#/components/responses/UnauthorizedError'
'402':
description: Payment required.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
examples:
insufficient-credits:
summary: Organisation balance is depleted
value:
detail: Insufficient credit balance. Please top up credits or upgrade your plan.
'403':
$ref: '#/components/responses/ForbiddenError'
'404':
$ref: '#/components/responses/NotFoundError'
'422':
description: Validation error.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
examples:
invalid-phone-number:
summary: Phone number failed request validation
value:
detail:
- loc:
- body
- phone_number
msg: String should match pattern '^\\+[1-9]\\d{1,14}$'
type: string_pattern_mismatch
'500':
$ref: '#/components/responses/InternalServerError'
'502':
description: Bad gateway.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
examples:
call-dispatch-failed:
summary: Upstream dispatch failure
value:
detail: 'Failed to dispatch call: upstream dispatcher unavailable'
get:
operationId: listAgentCalls
summary: List calls
description: List calls for a voice agent (paginated).
tags:
- Calls
parameters:
- $ref: '#/components/parameters/CallStatusQuery'
- $ref: '#/components/parameters/PageQuery'
- $ref: '#/components/parameters/PageSizeQuery'
responses:
'200':
description: Paginated calls.
content:
application/json:
schema:
$ref: '#/components/schemas/PaginatedAgentCallListOut'
'401':
$ref: '#/components/responses/UnauthorizedError'
'403':
$ref: '#/components/responses/ForbiddenError'
'404':
$ref: '#/components/responses/NotFoundError'
'422':
$ref: '#/components/responses/ValidationError'
'500':
$ref: '#/components/responses/InternalServerError'
/v1/agents/{agent_id}/calls/{call_id}:
parameters:
- $ref: '#/components/parameters/AgentIdPath'
- $ref: '#/components/parameters/CallIdPath'
get:
operationId: getCall
summary: Get call
description: Get details of a specific call.
tags:
- Calls
responses:
'200':
description: Call.
content:
application/json:
schema:
$ref: '#/components/schemas/AgentCallDetailOut'
'401':
$ref: '#/components/responses/UnauthorizedError'
'403':
$ref: '#/components/responses/ForbiddenError'
'404':
$ref: '#/components/responses/NotFoundError'
'422':
$ref: '#/components/responses/ValidationError'
'500':
$ref: '#/components/responses/InternalServerError'
/v1/agents/{agent_id}/calls/{call_id}/tool-executions:
parameters:
- $ref: '#/components/parameters/AgentIdPath'
- $ref: '#/components/parameters/CallIdPath'
post:
operationId: submitCallToolExecution
summary: Submit tool execution
description: 'Append a tool execution record to a call.
This endpoint is primarily used by SLNG-managed agent runtimes to report
contextual and system tool activity back to the Agents API.'
tags:
- Calls
x-hidden: true
requestBody:
required: true
content:
application/json:
schema:
$ref: '#/components/schemas/AgentCallToolExecutionCreate'
responses:
'204':
description: Tool execution recorded.
'401':
$ref: '#/components/responses/UnauthorizedError'
'403':
$ref: '#/components/responses/ForbiddenError'
'404':
$ref: '#/components/responses/NotFoundError'
'422':
$ref: '#/components/responses/ValidationError'
'500':
$ref: '#/components/responses/InternalServerError'
components:
schemas:
AgentCallDetailOut:
allOf:
- $ref: '#/components/schemas/AgentCallListItemOut'
- type: object
additionalProperties: false
properties:
livekit_session_report:
type:
- object
- 'null'
additionalProperties: true
description: Internal runtime diagnostics; structure may change.
call_events:
type: array
items:
$ref: '#/components/schemas/CallEvent'
tool_executions:
type: array
items:
$ref: '#/components/schemas/AgentCallToolExecutionClientOut'
UUID:
type: string
format: uuid
example: 550e8400-e29b-41d4-a716-446655440000
AgentCallResponse:
type: object
additionalProperties: false
required:
- call_id
- message
properties:
call_id:
$ref: '#/components/schemas/UUID'
message:
type: string
example: Call dispatched successfully
CallEvent:
type: object
additionalProperties: false
required:
- v
- created_at
- event
- level
properties:
v:
type: integer
minimum: 1
default: 1
created_at:
type: number
minimum: 0
event:
type: string
minLength: 1
maxLength: 200
level:
type: string
enum:
- debug
- info
- warning
- error
default: info
component:
type:
- string
- 'null'
enum:
- stt
- llm
- tts
from_model:
type:
- string
- 'null'
maxLength: 500
to_model:
type:
- string
- 'null'
maxLength: 500
reason:
type:
- string
- 'null'
enum:
- hard_fail
- timeout
timeout_s:
type:
- number
- 'null'
minimum: 0
error_type:
type:
- string
- 'null'
maxLength: 200
error_code:
type:
- integer
- 'null'
ErrorResponse:
type: object
additionalProperties: true
description: 'Error payloads can vary depending on where the error is raised (edge gateway vs backend).
Common shapes include:
- `{ "error": "message" }`
- `{ "detail": "message" }`
- `{ "detail": [ { "loc": [...], "msg": "...", "type": "..." } ] }` (validation)
'
properties:
error:
type: string
detail:
oneOf:
- type: string
- type: array
items:
type: object
DateTime:
type: string
format: date-time
example: '2026-01-15T10:30:00Z'
PaginationMeta:
type: object
additionalProperties: false
required:
- page
- page_size
- total
- pages
properties:
page:
type: integer
minimum: 1
page_size:
type: integer
minimum: 1
total:
type: integer
minimum: 0
pages:
type: integer
minimum: 0
PaginatedAgentCallListOut:
type: object
additionalProperties: false
required:
- items
- meta
properties:
items:
type: array
items:
$ref: '#/components/schemas/AgentCallListItemOut'
meta:
$ref: '#/components/schemas/PaginationMeta'
ToolInvocationSource:
type: string
enum:
- system
- contextual
AgentCallCreate:
type: object
additionalProperties: false
required:
- phone_number
properties:
phone_number:
type: string
description: E.164 format phone number or template that resolves to E.164.
arguments:
type: object
maxProperties: 32
additionalProperties:
type: string
maxLength: 1024
default: {}
description: Per-call template argument overrides. Maximum 32 keys. Each value may be up to 1024 characters. Combined value payload may not exceed 8192 characters.
AgentCallListItemOut:
type: object
additionalProperties: false
required:
- id
- agent_id
- phone_number
- call_direction
- arguments
- rendered_prompt
- livekit_room_name
- status
- created_at
- updated_at
properties:
id:
$ref: '#/components/schemas/UUID'
agent_id:
$ref: '#/components/schemas/UUID'
phone_number:
type: string
call_direction:
type: string
web_session_origin:
type:
- string
- 'null'
enum:
- dashboard_test
- api
arguments:
type: object
additionalProperties: true
rendered_prompt:
type: string
livekit_room_name:
type: string
description: Internal runtime identifier.
livekit_dispatch_id:
type:
- string
- 'null'
description: Internal dispatch identifier.
call_started_at:
$ref: '#/components/schemas/NullableDateTime'
call_ended_at:
$ref: '#/components/schemas/NullableDateTime'
call_duration_ms:
type:
- integer
- 'null'
call_end_reason:
type:
- string
- 'null'
finalized_at:
$ref: '#/components/schemas/NullableDateTime'
call_duration_source:
type:
- string
- 'null'
status:
type: string
error_message:
type:
- string
- 'null'
created_at:
$ref: '#/components/schemas/DateTime'
updated_at:
$ref: '#/components/schemas/DateTime'
AgentCallToolExecutionClientOut:
type: object
additionalProperties: false
required:
- tool_name
- tool_kind
- invocation_source
- started_at
- finished_at
- duration_ms
- outcome
properties:
tool_name:
type: string
tool_kind:
$ref: '#/components/schemas/ToolExecutionKind'
invocation_source:
$ref: '#/components/schemas/ToolInvocationSource'
trigger_event:
type:
- string
- 'null'
started_at:
$ref: '#/components/schemas/DateTime'
finished_at:
$ref: '#/components/schemas/DateTime'
duration_ms:
type: integer
outcome:
$ref: '#/components/schemas/ToolExecutionOutcome'
http_status:
type:
- integer
- 'null'
error_code:
type:
- string
- 'null'
error_type:
type:
- string
- 'null'
NullableDateTime:
type:
- string
- 'null'
format: date-time
example: '2026-01-15T10:30:00Z'
ToolExecutionKind:
type: string
enum:
- webhook
- template
- human_transfer
- built_in
ToolExecutionOutcome:
type: string
enum:
- succeeded
- failed
- timed_out
- skipped
- cancelled
AgentCallToolExecutionCreate:
type: object
additionalProperties: false
required:
- tool_name
- tool_kind
- invocation_source
- started_at
- finished_at
- duration_ms
- outcome
properties:
tool_id:
type:
- string
- 'null'
maxLength: 255
tool_name:
type: string
minLength: 1
maxLength: 255
tool_kind:
$ref: '#/components/schemas/ToolExecutionKind'
invocation_source:
$ref: '#/components/schemas/ToolInvocationSource'
trigger_event:
type:
- string
- 'null'
minLength: 1
maxLength: 64
source_tool_id:
type:
- string
- 'null'
maxLength: 255
started_at:
$ref: '#/components/schemas/DateTime'
finished_at:
$ref: '#/components/schemas/DateTime'
duration_ms:
type: integer
minimum: 0
outcome:
$ref: '#/components/schemas/ToolExecutionOutcome'
http_status:
type:
- integer
- 'null'
minimum: 100
maximum: 999
error_code:
type:
- string
- 'null'
maxLength: 128
error_type:
type:
- string
- 'null'
maxLength: 200
wait_for_response:
type:
- boolean
- 'null'
show_results_to_llm:
type:
- boolean
- 'null'
target_url:
type:
- string
- 'null'
maxLength: 1024
description: Sanitized target URL without query string or fragment details.
arguments_preview: {}
result_preview: {}
error_message:
type:
- string
- 'null'
maxLength: 5000
stack_trace:
type:
- string
- 'null'
maxLength: 20000
parameters:
PageSizeQuery:
name: page_size
in: query
required: false
schema:
type: integer
minimum: 1
description: Page size.
AgentIdPath:
name: agent_id
in: path
required: true
schema:
$ref: '#/components/schemas/UUID'
description: Voice agent ID.
CallIdPath:
name: call_id
in: path
required: true
schema:
$ref: '#/components/schemas/UUID'
description: Call ID.
CallStatusQuery:
name: status
in: query
required: false
schema:
type: string
description: Filter calls by status.
PageQuery:
name: page
in: query
required: false
schema:
type: integer
minimum: 1
default: 1
description: Page number (1-indexed).
responses:
UnauthorizedError:
description: Unauthorized.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
examples:
unauthorized:
summary: Authentication failed
value:
detail: Authentication is required for this endpoint.
NotFoundError:
description: Not found.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
examples:
not-found:
summary: Resource not found
value:
detail: The requested resource was not found.
ValidationError:
description: Validation error.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
examples:
validation-error:
summary: Request validation failed
value:
detail:
- loc:
- body
- language
msg: Input should be a valid string
type: string_type
InternalServerError:
description: Internal server error.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
examples:
internal-server-error:
summary: Unexpected application error
value:
detail: An unexpected internal error occurred.
ForbiddenError:
description: Forbidden.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
examples:
forbidden:
summary: Access denied
value:
detail: You do not have access to this resource.
securitySchemes:
bearerAuth:
type: http
scheme: bearer
bearerFormat: API key