Python SDK

Installation

pip install iii-sdk

Initialization

register_worker

Register the worker with a iii instance, returns a connected worker client. Blocks until the WebSocket connection is established and ready. Signature

register_worker(address: str, options: InitOptions | None = None) -> III

Parameters
Example

address

str

required

WebSocket URL of the III engine (e.g. ws://localhost:49134).

options

InitOptions | None

Optional configuration for worker name, timeouts, reconnection, and OTel.

Show `InitOptions` fields

enable_metrics_reporting

bool

Enable worker metrics via OpenTelemetry. Default True.

headers

dict[str, str] | None

invocation_timeout_ms

int

Default timeout for worker.trigger() invocations in milliseconds. Default 30000.

otel

OtelConfig | dict[str, Any] | None

OpenTelemetry configuration. Enabled by default. Set \{'enabled': False\} or env OTEL_ENABLED=false to disable.

reconnection_config

ReconnectionConfig | None

WebSocket reconnection behavior.

telemetry

TelemetryOptions | None

Internal worker metadata reported to the engine.

worker_description

str | None

One-line, human/LLM-readable summary of what this worker does. Surfaces in engine::workers::list / engine::workers::info.

worker_name

str | None

Display name for this worker. Defaults to hostname:pid.

from iii import register_worker, InitOptions
worker = register_worker('ws://localhost:49134', InitOptions(worker_name='my-worker'))

Methods

register_trigger

Bind a trigger configuration to a registered function. Signature

register_trigger(trigger: RegisterTriggerInput | dict[str, Any]) -> Trigger

Parameters
Example

trigger

RegisterTriggerInput | dict[str, Any]

required

A RegisterTriggerInput or dict with type, function_id, and optional config.

Hide `RegisterTriggerInput` fields

config

Any

Trigger-type-specific configuration, matching the shape the trigger type expects.

function_id

str

required

ID of the function this trigger invokes when it fires.

metadata

Any | None

Arbitrary user-specifiable metadata supplied to the triggered handler function on every invocation.

type

str

required

Identifier of the registered trigger type this trigger uses (e.g. storage::object-created, http).

trigger = worker.register_trigger({
  'type': 'http',
  'function_id': 'greet',
  'config': {'api_path': '/greet', 'http_method': 'GET'}
})
trigger = worker.register_trigger(RegisterTriggerInput(
    type="http", function_id="greet",
    config={'api_path': '/greet', 'http_method': 'GET'}
))
trigger.unregister()

register_function

Register a function with the engine. Pass a handler for local execution, or an HttpInvocationConfig for HTTP-invoked functions (Lambda, Cloudflare Workers, etc.). Handlers can be synchronous or asynchronous. Sync handlers are automatically wrapped with run_in_executor so they do not block the event loop. Each handler receives a data argument containing the trigger payload, and may optionally accept a second metadata argument carrying per-invocation metadata (e.g. def handler(data, metadata=None) or def handler(data, *, metadata=None)). Metadata is only forwarded to handlers that declare a parameter literally named metadata, so existing handlers, including ones with unrelated extra parameters, *args, or **kwargs, keep working unchanged. request_format and response_format are auto-extracted from the handler’s type hints when omitted or passed as None (the default). To opt out of auto-extraction, pass an explicit schema (RegisterFunctionFormat or dict). This behavior is Python-specific; the Node SDK relies on explicit schemas because TypeScript types are erased at runtime. Signature

register_function(function_id: str, handler_or_invocation: RemoteFunctionHandler | HttpInvocationConfig, *, description: str | None = None, metadata: dict[str, Any] | None = None, request_format: RegisterFunctionFormat | dict[str, Any] | None = None, response_format: RegisterFunctionFormat | dict[str, Any] | None = None) -> FunctionRef

Parameters
Example

function_id

str

required

Unique string identifier for the function.

handler_or_invocation

RemoteFunctionHandler | HttpInvocationConfig

required

A callable handler or HttpInvocationConfig. Callable handlers receive data (the trigger payload) as the first argument and may optionally accept metadata (per-invocation metadata) as a second argument; they may return a value.

description

str | None

Human-readable description of what the function does.

metadata

dict[str, Any] | None

Arbitrary metadata attached to the function.

request_format

RegisterFunctionFormat | dict[str, Any] | None

Schema describing expected input. When None (default), auto-extracted from the handler’s first-parameter type hint. Pass an explicit schema to override; there is no way to register with no schema when the handler is typed.

Show `RegisterFunctionFormat` fields

body

list[RegisterFunctionFormat] | None

Nested fields for object types.

description

str | None

Human-readable description of the parameter.

items

RegisterFunctionFormat | None

Item schema for array types.

name

str

required

Parameter name.

required

bool

Whether the parameter is required.

type

str

required

Type string (string, number, boolean, object, array, null, map).

response_format

RegisterFunctionFormat | dict[str, Any] | None

Schema describing expected output. Same auto-extraction semantics as request_format.

def greet(data):
    return {'message': f"Hello, {data['name']}!"}
fn = worker.register_function("greet", greet, description="Greets a user")
fn.unregister()
from pydantic import BaseModel
class GreetInput(BaseModel):
    name: str
class GreetOutput(BaseModel):
    message: str
async def greet(data: GreetInput) -> GreetOutput:
    return GreetOutput(message=f"Hello, {data.name}!")
fn = worker.register_function("greet", greet, description="Greets a user")

trigger

Invoke a remote function. The routing behavior and return type depend on the action field:

No action: synchronous, waits for the function to return.
TriggerAction.Enqueue(...): async via named queue, returns a dict with messageReceiptId.
TriggerAction.Void(): fire-and-forget, returns None.

Signature

trigger(request: dict[str, Any] | TriggerRequest) -> Any

Parameters
Example

request

dict[str, Any] | TriggerRequest

required

A TriggerRequest or dict with function_id, payload, and optional action / timeout_ms.

Hide `TriggerRequest` fields

action

TriggerActionEnqueue | TriggerActionVoid | None

Sets how the trigger is routed. Omit for a synchronous request/response. Specify for a specific routing scheme (e.g. TriggerAction.Enqueue(...), TriggerAction.Void()).

function_id

str

required

ID of the function to invoke.

metadata

Any | None

Arbitrary user-specifiable metadata supplied to the triggered handler function on every invocation.

payload

Any

Input data passed to the function.

timeout_ms

int | None

Override the default invocation timeout, in milliseconds.

result = worker.trigger({'function_id': 'greet', 'payload': {'name': 'World'}})
worker.trigger({'function_id': 'notify', 'payload': {}, 'action': TriggerAction.Void()})

register_trigger_type

Register a custom trigger type with the engine. Returns a :class:TriggerTypeRef handle with register_trigger and register_function methods. Signature

register_trigger_type(trigger_type: RegisterTriggerTypeInput | dict[str, Any], handler: TriggerHandler[Any]) -> TriggerTypeRef[Any, Any]

Parameters
Example

trigger_type

RegisterTriggerTypeInput | dict[str, Any]

required

A RegisterTriggerTypeInput or dict with id, description, and optional trigger_request_format / call_request_format (Pydantic class or dict).

Show `RegisterTriggerTypeInput` fields

call_request_format

Any | None

JSON Schema describing the payload sent to functions.

description

str

required

Human-readable description of what this trigger type does.

str

required

Unique identifier for the trigger type (e.g. state, durable:subscriber).

trigger_request_format

Any | None

JSON Schema describing the expected trigger config.

handler

TriggerHandler[Any]

required

A TriggerHandler instance.

Show `TriggerHandler` fields

register_trigger

async (config: TriggerConfig[TConfig]) -> None

required

unregister_trigger

async (config: TriggerConfig[TConfig]) -> None

required

Unregister a trigger with the given configuration.

webhook = worker.register_trigger_type(
    RegisterTriggerTypeInput(
        id="webhook",
        description="Webhook trigger",
        trigger_request_format=WebhookConfig,
        call_request_format=WebhookCallRequest,
    ),
    WebhookHandler(),
)
webhook.register_function("handler", handle_webhook)
webhook.register_trigger("handler", WebhookConfig(url="/hook"))

unregister_trigger_type

Unregister a previously registered trigger type. Signature

unregister_trigger_type(trigger_type: RegisterTriggerTypeInput | dict[str, Any]) -> None

Parameters
Example

trigger_type

RegisterTriggerTypeInput | dict[str, Any]

required

A RegisterTriggerTypeInput or dict with id and optional description.

Show `RegisterTriggerTypeInput` fields

call_request_format

Any | None

JSON Schema describing the payload sent to functions.

description

str

required

Human-readable description of what this trigger type does.

str

required

Unique identifier for the trigger type (e.g. state, durable:subscriber).

trigger_request_format

Any | None

JSON Schema describing the expected trigger config.

worker.unregister_trigger_type({"id": "webhook", "description": "Webhook trigger"})
worker.unregister_trigger_type(RegisterTriggerTypeInput(id="webhook", description="Webhook trigger"))

connect_async

Connect to the III Engine via WebSocket. Initializes OpenTelemetry (if configured), attaches the event loop, and establishes the WebSocket connection. This is called automatically during construction; use it only if you need to reconnect manually from an async context. Signature

async () -> None

get_connection_state

Return the current WebSocket connection state. Signature

get_connection_state() -> IIIConnectionState

Example

worker = register_worker("ws://localhost:49134")
if worker.get_connection_state() != "connected":
    print("engine not reachable yet")

shutdown

Gracefully shut down the client, releasing all resources. Cancels any pending reconnection attempts, rejects all in-flight invocations with an error, closes the WebSocket connection, and stops the background event-loop thread. After this call the instance must not be reused. Signature

shutdown() -> None

Example

worker = register_worker('ws://localhost:49134')
# ... do work ...
worker.shutdown()

shutdown_async

async () -> None

Example

worker = register_worker('ws://localhost:49134')
# ... do work ...
await worker.shutdown_async()

trigger_async

Invoke a remote function. The routing behavior and return type depend on the action field:

No action: synchronous, waits for the function to return.
TriggerAction.Enqueue(...): async via named queue, returns a dict with messageReceiptId.
TriggerAction.Void(): fire-and-forget, returns None.

Signature

async (request: dict[str, Any] | TriggerRequest) -> Any

Parameters
Example

request

dict[str, Any] | TriggerRequest

required

A TriggerRequest or dict with function_id, payload, and optional action / timeout_ms.

Show `TriggerRequest` fields

action

TriggerActionEnqueue | TriggerActionVoid | None

Sets how the trigger is routed. Omit for a synchronous request/response. Specify for a specific routing scheme (e.g. TriggerAction.Enqueue(...), TriggerAction.Void()).

function_id

str

required

ID of the function to invoke.

metadata

Any | None

Arbitrary user-specifiable metadata supplied to the triggered handler function on every invocation.

payload

Any

Input data passed to the function.

timeout_ms

int | None

Override the default invocation timeout, in milliseconds.

result = await worker.trigger_async({'function_id': 'greet', 'payload': {'name': 'World'}})
await worker.trigger_async({'function_id': 'notify', 'payload': {}, 'action': TriggerAction.Void()})

Types

iii

EnqueueResult · InitOptions · MiddlewareFunctionInput · StreamRequest · StreamResponse · TelemetryOptions · TriggerAction · TriggerActionEnqueue

EnqueueResult

Result returned when a function is invoked with TriggerAction.Enqueue.

Name	Type	Required	Description
`messageReceiptId`	`str`	Yes	Unique receipt ID for the enqueued message.

InitOptions

Configuration options passed to register_worker.

Name	Type	Required	Description
`enable_metrics_reporting`	`bool`	No	Enable worker metrics via OpenTelemetry. Default `True`.
`headers`	`dict[str, str] \| None`	No	-
`invocation_timeout_ms`	`int`	No	Default timeout for `worker.trigger()` invocations in milliseconds. Default `30000`.
`otel`	`OtelConfig \| dict[str, Any] \| None`	No	OpenTelemetry configuration. Enabled by default. Set `\{'enabled': False\}` or env `OTEL_ENABLED=false` to disable.
`reconnection_config`	`ReconnectionConfig \| None`	No	WebSocket reconnection behavior.
`telemetry`	`TelemetryOptions` \| None	No	Internal worker metadata reported to the engine.
`worker_description`	`str \| None`	No	One-line, human/LLM-readable summary of what this worker does. Surfaces in `engine::workers::list` / `engine::workers::info`.
`worker_name`	`str \| None`	No	Display name for this worker. Defaults to `hostname:pid`.

MiddlewareFunctionInput

Input passed to the RBAC middleware function on every function invocation through the RBAC port.

Name	Type	Required	Description
`action`	`TriggerActionEnqueue` \| `TriggerActionVoid` \| None	No	Routing action, if any.
`context`	`dict[str, Any]`	Yes	Auth context returned by the auth function for this session.
`function_id`	`str`	Yes	ID of the function being invoked.
`payload`	`dict[str, Any]`	Yes	Payload sent by the caller.

StreamRequest

Incoming streaming request received by a function registered with a stream trigger.

Name	Type	Required	Description
`body`	`Any`	Yes	-
`headers`	`dict[str, str \| list[str]]`	Yes	-
`method`	`str`	Yes	-
`path_params`	`dict[str, str]`	Yes	-
`query_params`	`dict[str, str \| list[str]]`	Yes	-
`request_body`	`ChannelReader`	Yes	-

StreamResponse

Streaming response built on top of a ChannelWriter.

Name	Type	Required	Description
`close`	`() -> None`	Yes	-
`headers`	`async (headers: dict[str, str]) -> None`	Yes	-
`status`	`async (status_code: int) -> None`	Yes	-
`stream`	`WritableStream`	Yes	-
`writer`	`ChannelWriter`	Yes	-

TelemetryOptions

Worker metadata reported to the engine (language, framework, project).

Name	Type	Required	Description
`amplitude_api_key`	`str \| None`	No	Amplitude API key for product analytics.
`framework`	`str \| None`	No	Framework name, if applicable.
`language`	`str \| None`	No	Programming language of the worker.
`project_name`	`str \| None`	No	Name of the project this worker belongs to.

TriggerAction

Factory for creating trigger actions used with trigger().

Name	Type	Required	Description
`Enqueue`	(*, queue: str) -> `TriggerActionEnqueue`	Yes	Route the invocation through a named queue for async processing.
`Void`	() -> `TriggerActionVoid`	Yes	Fire-and-forget routing. No response is returned.

TriggerActionEnqueue

Routes the invocation through a named queue for async processing. Requires a queue worker in the project. Run iii worker add queue. Without it the trigger rejects with enqueue_error (no queue provider).

Name	Type	Required	Description
`queue`	`str`	Yes	Name of the target queue.
`type`	`Literal['enqueue']`	No	Always `'enqueue'`.

iii.channel

Channel · ChannelReader · ChannelWriter · StreamChannelRef

Channel

A streaming channel pair for worker-to-worker data transfer.

Name	Type	Required	Description
`reader`	`ChannelReader`	Yes	-
`reader_ref`	`StreamChannelRef`	Yes	-
`writer`	`ChannelWriter`	Yes	-
`writer_ref`	`StreamChannelRef`	Yes	-

ChannelReader

WebSocket-backed reader for streaming binary data and text messages.

Name	Type	Required	Description
`close_async`	`async () -> None`	Yes	-
`on_message`	`(callback: Callable[[str], Any]) -> None`	Yes	-
`read_all`	`async () -> bytes`	Yes	Read the entire stream into a single bytes object.
`stream`	`Any`	No	-

ChannelWriter

WebSocket-backed writer for streaming binary data and text messages.

Name	Type	Required	Description
`close`	`() -> None`	Yes	Fire-and-forget close.
`close_async`	`async () -> None`	Yes	-
`send_message`	`(msg: str) -> None`	Yes	Fire-and-forget text message. Queues a coroutine on the running loop.
`send_message_async`	`async (msg: str) -> None`	Yes	-
`stream`	`Any`	No	-
`write`	`async (data: bytes) -> None`	Yes	-

StreamChannelRef

Reference to a streaming channel for worker-to-worker data transfer.

Name	Type	Required	Description
`access_key`	`str`	Yes	Secret key for authenticating channel access.
`channel_id`	`str`	Yes	Unique channel identifier.
`direction`	`Literal['read', 'write']`	Yes	Channel direction (`read` or `write`).

iii.engine

EngineFunctions · EngineTriggers

EngineFunctions

Engine function ids for internal operations (parity with the Node SDK).

Name	Type	Required	Description
`INFO_FUNCTIONS`	`Final[str]`	No	-
`INFO_REGISTERED_TRIGGERS`	`Final[str]`	No	-
`INFO_TRIGGERS`	`Final[str]`	No	-
`INFO_WORKERS`	`Final[str]`	No	-
`LIST_FUNCTIONS`	`Final[str]`	No	-
`LIST_REGISTERED_TRIGGERS`	`Final[str]`	No	-
`LIST_TRIGGERS`	`Final[str]`	No	-
`LIST_WORKERS`	`Final[str]`	No	-
`REGISTER_WORKER`	`Final[str]`	No	-

EngineTriggers

Engine trigger ids (parity with the Node SDK).

Name	Type	Required	Description
`FUNCTIONS_AVAILABLE`	`Final[str]`	No	-
`LOG`	`Final[str]`	No	-

iii.errors

InvocationError

InvocationError

Raised when an invocation dispatched by the SDK fails. Inspect err.code to react to a specific category (e.g. 'FORBIDDEN' for RBAC denials, 'TIMEOUT' for timeouts). Catch this class to handle every rejection. except Exception continues to work because InvocationError inherits from Exception. Attributes are read-only after construction. stacktrace is the engine-side trace when the remote handler raised; it may include internal file paths and should not be surfaced to end users. str(err) intentionally never includes the stacktrace.

Name	Type	Required	Description
`code`	`Any`	No	-
`function_id`	`Any`	No	-
`invocation_id`	`Any`	No	-
`message`	`Any`	No	-
`stacktrace`	`Any`	No	-

iii.protocol

MessageType · RegisterFunctionFormat · RegisterFunctionInput · RegisterFunctionMessage · RegisterTriggerInput · RegisterTriggerMessage · RegisterTriggerTypeInput · RegisterTriggerTypeMessage · TriggerRequest

MessageType

Message types for iii communication.

Name	Type	Required	Description
`INVOCATION_RESULT`	`Any`	No	-
`INVOKE_FUNCTION`	`Any`	No	-
`REGISTER_FUNCTION`	`Any`	No	-
`REGISTER_SERVICE`	`Any`	No	-
`REGISTER_TRIGGER`	`Any`	No	-
`REGISTER_TRIGGER_TYPE`	`Any`	No	-
`TRIGGER_REGISTRATION_RESULT`	`Any`	No	-
`UNREGISTER_FUNCTION`	`Any`	No	-
`UNREGISTER_TRIGGER`	`Any`	No	-
`UNREGISTER_TRIGGER_TYPE`	`Any`	No	-
`WORKER_REGISTERED`	`Any`	No	-

RegisterFunctionFormat

Format definition for function parameters.

Name	Type	Required	Description
`body`	list[`RegisterFunctionFormat`] \| None	No	Nested fields for object types.
`description`	`str \| None`	No	Human-readable description of the parameter.
`items`	`RegisterFunctionFormat` \| None	No	Item schema for array types.
`name`	`str`	Yes	Parameter name.
`required`	`bool`	No	Whether the parameter is required.
`type`	`str`	Yes	Type string (`string`, `number`, `boolean`, `object`, `array`, `null`, `map`).

RegisterFunctionInput

Input for registering a function, matches Node.js RegisterFunctionInput.

Name	Type	Required	Description
`description`	`str \| None`	No	Human-readable description.
`id`	`str`	Yes	Unique function identifier.
`invocation`	`HttpInvocationConfig \| None`	No	HTTP invocation config for externally hosted functions.
`metadata`	`Any \| None`	No	Arbitrary metadata attached to the function.
`request_format`	`RegisterFunctionFormat` \| dict[str, Any] \| None	No	Schema describing expected input.
`response_format`	`RegisterFunctionFormat` \| dict[str, Any] \| None	No	Schema describing expected output.

RegisterFunctionMessage

Name	Type	Required	Description
`description`	`str \| None`	No	-
`id`	`str`	Yes	-
`invocation`	`HttpInvocationConfig \| None`	No	-
`message_type`	`MessageType`	No	-
`metadata`	`Any \| None`	No	-
`request_format`	`RegisterFunctionFormat` \| dict[str, Any] \| None	No	-
`response_format`	`RegisterFunctionFormat` \| dict[str, Any] \| None	No	-

RegisterTriggerInput

Input for registering a trigger (matches Node SDK’s RegisterTriggerInput).

Name	Type	Required	Description
`config`	`Any`	No	Trigger-type-specific configuration, matching the shape the trigger type expects.
`function_id`	`str`	Yes	ID of the function this trigger invokes when it fires.
`metadata`	`Any \| None`	No	Arbitrary user-specifiable metadata supplied to the triggered handler function on every invocation.
`type`	`str`	Yes	Identifier of the registered trigger type this trigger uses (e.g. `storage::object-created`, `http`).

RegisterTriggerMessage

Name	Type	Required	Description
`config`	`Any`	Yes	-
`function_id`	`str`	Yes	-
`id`	`str`	Yes	-
`message_type`	`MessageType`	No	-
`metadata`	`Any \| None`	No	-
`trigger_type`	`str`	Yes	-

RegisterTriggerTypeInput

Input for registering a trigger type.

Name	Type	Required	Description
`call_request_format`	`Any \| None`	No	JSON Schema describing the payload sent to functions.
`description`	`str`	Yes	Human-readable description of what this trigger type does.
`id`	`str`	Yes	Unique identifier for the trigger type (e.g. `state`, `durable:subscriber`).
`trigger_request_format`	`Any \| None`	No	JSON Schema describing the expected trigger config.

RegisterTriggerTypeMessage

Name	Type	Required	Description
`call_request_format`	`Any \| None`	No	-
`description`	`str`	Yes	-
`id`	`str`	Yes	-
`message_type`	`MessageType`	No	-
`trigger_request_format`	`Any \| None`	No	-

TriggerRequest

Request object for trigger().

Name	Type	Required	Description
`action`	`TriggerActionEnqueue` \| `TriggerActionVoid` \| None	No	Sets how the trigger is routed. Omit for a synchronous request/response. Specify for a specific routing scheme (e.g. `TriggerAction.Enqueue(...)`, `TriggerAction.Void()`).
`function_id`	`str`	Yes	ID of the function to invoke.
`metadata`	`Any \| None`	No	Arbitrary user-specifiable metadata supplied to the triggered handler function on every invocation.
`payload`	`Any`	No	Input data passed to the function.
`timeout_ms`	`int \| None`	No	Override the default invocation timeout, in milliseconds.

iii.runtime

FunctionRef · TriggerTypeRef

FunctionRef

Reference to a registered function, allowing programmatic unregistration.

Name	Type	Required	Description
`id`	`str`	Yes	The unique function identifier.
`unregister`	`Callable[[], None]`	Yes	Removes this function from the engine.

TriggerTypeRef

Typed handle returned by :meth:iii.III.register_trigger_type. Type parameters:

C: configuration type for :meth:register_trigger
R: call-request type for :meth:register_function

Name	Type	Required	Description
`register_function`	`(function_id: str, handler: Callable[[R], Any] \| Callable[[R], Awaitable[Any]], *, description: str \| None = None) -> Any`	Yes	Register a function whose input matches the call-request format.
`register_trigger`	(function_id: str, config: C, metadata: dict[str, Any] \| None = None) -> `Trigger`	Yes	Register a trigger with validated config.

iii.state

IState · StateDeleteInput · StateDeleteResult · StateEventData · StateEventType · StateGetInput · StateListInput · StateSetInput · StateSetResult · StateUpdateInput · StateUpdateResult

IState

Abstract interface for state management operations.

Name	Type	Required	Description
`delete`	async (input: `StateDeleteInput`) -> `StateDeleteResult`	Yes	Delete a state value.
`get`	async (input: `StateGetInput`) -> TData \| None	Yes	Retrieve a value by scope and key.
`list`	async (input: `StateListInput`) -> list[TData]	Yes	List all values in a scope.
`set`	async (input: `StateSetInput`) -> `StateSetResult`[TData] \| None	Yes	Set (create or overwrite) a state value.
`update`	async (input: `StateUpdateInput`) -> `StateUpdateResult`[TData] \| None	Yes	Apply atomic update operations to a state value.

StateDeleteInput

Input for deleting a state value.

Name	Type	Required	Description
`key`	`str`	Yes	Key within the scope.
`scope`	`str`	Yes	State scope (namespace).

StateDeleteResult

Result of a state delete operation.

Name	Type	Required	Description
`old_value`	`Any \| None`	No	Previous value (if it existed).

StateEventData

Payload for state change events.

Name	Type	Required	Description
`event_type`	`StateEventType`	Yes	Type of state change.
`key`	`str`	Yes	Key within the scope.
`new_value`	`TData \| None`	No	New value (for create/update events).
`old_value`	`TData \| None`	No	Previous value (for update/delete events).
`scope`	`str`	Yes	State scope (namespace).
`type`	`str`	No	Event category (always `state`).

StateEventType

Types of state change events.

Name	Type	Required	Description
`CREATED`	`Any`	No	-
`DELETED`	`Any`	No	-
`UPDATED`	`Any`	No	-

StateGetInput

Input for retrieving a state value.

Name	Type	Required	Description
`key`	`str`	Yes	Key within the scope.
`scope`	`str`	Yes	State scope (namespace).

StateListInput

Input for listing all values in a state scope.

Name	Type	Required	Description
`scope`	`str`	Yes	State scope (namespace).

StateSetInput

Input for setting a state value.

Name	Type	Required	Description
`key`	`str`	Yes	Key within the scope.
`scope`	`str`	Yes	State scope (namespace).
`value`	`Any`	Yes	Value to store.

StateSetResult

Result of a state set operation.

Name	Type	Required	Description
`new_value`	`TData`	Yes	New value that was stored.
`old_value`	`TData \| None`	No	Previous value (if it existed).

StateUpdateInput

Input for atomically updating a state value.

Name	Type	Required	Description
`key`	`str`	Yes	Key within the scope.
`ops`	`list[UpdateOp]`	Yes	Ordered list of update operations to apply atomically.
`scope`	`str`	Yes	State scope (namespace).

StateUpdateResult

Result of a state update operation.

Name	Type	Required	Description
`new_value`	`TData`	Yes	New value after the update.
`old_value`	`TData \| None`	No	Previous value (if it existed).

iii.stream

IStream · StreamDeleteInput · StreamDeleteResult · StreamGetInput · StreamListGroupsInput · StreamListInput · StreamSetInput · StreamSetResult · StreamUpdateInput · StreamUpdateResult

IStream

Abstract interface for stream operations.

Name	Type	Required	Description
`delete`	async (input: `StreamDeleteInput`) -> `StreamDeleteResult`	Yes	Delete an item from the stream.
`get`	async (input: `StreamGetInput`) -> TData \| None	Yes	Get an item from the stream.
`list`	async (input: `StreamListInput`) -> list[TData]	Yes	Get all items in a group.
`list_groups`	async (input: `StreamListGroupsInput`) -> List[str]	Yes	List all groups in the stream.
`set`	async (input: `StreamSetInput`) -> `StreamSetResult`[TData] \| None	Yes	Set an item in the stream.
`update`	async (input: `StreamUpdateInput`) -> `StreamUpdateResult`[TData] \| None	Yes	Apply atomic update operations to a stream item.

StreamDeleteInput

Input for stream delete operation.

Name	Type	Required	Description
`group_id`	`str`	Yes	Group identifier.
`item_id`	`str`	Yes	Item identifier.
`stream_name`	`str`	Yes	Name of the stream.

StreamDeleteResult

Result of stream delete operation.

Name	Type	Required	Description
`old_value`	`Any \| None`	No	Previous value (if it existed).

StreamGetInput

Input for stream get operation.

Name	Type	Required	Description
`group_id`	`str`	Yes	Group identifier.
`item_id`	`str`	Yes	Item identifier.
`stream_name`	`str`	Yes	Name of the stream.

StreamListGroupsInput

Input for stream list groups operation.

Name	Type	Required	Description
`stream_name`	`str`	Yes	Name of the stream.

StreamListInput

Input for stream list operation.

Name	Type	Required	Description
`group_id`	`str`	Yes	Group identifier.
`stream_name`	`str`	Yes	Name of the stream.

StreamSetInput

Input for stream set operation.

Name	Type	Required	Description
`data`	`Any`	Yes	Data to store.
`group_id`	`str`	Yes	Group identifier.
`item_id`	`str`	Yes	Item identifier.
`stream_name`	`str`	Yes	Name of the stream.

StreamSetResult

Result of stream set operation.

Name	Type	Required	Description
`new_value`	`TData`	Yes	New value that was stored.
`old_value`	`TData \| None`	No	Previous value (if it existed).

StreamUpdateInput

Input for stream update operation.

Name	Type	Required	Description
`group_id`	`str`	Yes	Group identifier.
`item_id`	`str`	Yes	Item identifier.
`ops`	`list['UpdateOp']`	Yes	Ordered list of update operations to apply atomically.
`stream_name`	`str`	Yes	Name of the stream.

StreamUpdateResult

Result of stream update operation.

Name	Type	Required	Description
`errors`	`list[UpdateOpError]`	No	Per-op errors. Emitted by `merge` and `append` for validation rejections (path depth/size, value depth, or a `__proto__` / `constructor` / `prototype` segment or top-level key) and by `append` for the `append.type_mismatch` and `append.target_not_object` surfaces. Successfully applied ops are still reflected in `new_value`. The field is omitted from the JSON wire when empty.
`new_value`	`TData`	Yes	New value after the update.
`old_value`	`TData \| None`	No	Previous value (if it existed).

iii.trigger

Trigger · TriggerActionVoid · TriggerConfig · TriggerHandler

Trigger

Represents a registered trigger.

Name	Type	Required	Description
`unregister`	`() -> None`	Yes	Unregister this trigger.

TriggerActionVoid

Fire-and-forget routing. No response is returned.

Name	Type	Required	Description
`type`	`Literal['void']`	No	Always `'void'`.

TriggerConfig

Configuration passed to a trigger handler when a trigger instance is registered or unregistered.

Name	Type	Required	Description
`config`	`Any`	Yes	Trigger-specific configuration.
`function_id`	`str`	Yes	Function to invoke when the trigger fires.
`id`	`str`	Yes	Trigger instance ID.
`metadata`	`dict[str, Any] \| None`	No	Arbitrary user-specifiable metadata supplied to the triggered handler function on every invocation.

TriggerHandler

Abstract base class for trigger handlers.

Name	Type	Required	Description
`register_trigger`	async (config: `TriggerConfig`[TConfig]) -> None	Yes	Register a trigger with the given configuration.
`unregister_trigger`	async (config: `TriggerConfig`[TConfig]) -> None	Yes	Unregister a trigger with the given configuration.

​Installation

​Initialization

​register_worker

​Methods

​register_trigger

​register_function

​trigger

​register_trigger_type

​unregister_trigger_type

​connect_async

​get_connection_state

​Example

​shutdown

​Example

​shutdown_async

​Example

​trigger_async

​Types

​iii

​EnqueueResult

​InitOptions

​MiddlewareFunctionInput

​StreamRequest

​StreamResponse

​TelemetryOptions

​TriggerAction

​TriggerActionEnqueue

​iii.channel

​Channel

​ChannelReader

​ChannelWriter

​StreamChannelRef

​iii.engine

​EngineFunctions

​EngineTriggers

​iii.errors

​InvocationError

​iii.protocol

​MessageType

​RegisterFunctionFormat

​RegisterFunctionInput

​RegisterFunctionMessage

​RegisterTriggerInput

​RegisterTriggerMessage

​RegisterTriggerTypeInput

​RegisterTriggerTypeMessage

​TriggerRequest

​iii.runtime

​FunctionRef

​TriggerTypeRef

​iii.state

​IState

​StateDeleteInput

​StateDeleteResult

​StateEventData

​StateEventType

​StateGetInput

​StateListInput

​StateSetInput

​StateSetResult

​StateUpdateInput

​StateUpdateResult

​iii.stream

​IStream

​StreamDeleteInput

​StreamDeleteResult

​StreamGetInput

​StreamListGroupsInput

​StreamListInput

​StreamSetInput

​StreamSetResult

​StreamUpdateInput

​StreamUpdateResult

​iii.trigger

​Trigger

​TriggerActionVoid

​TriggerConfig

​TriggerHandler

Installation

Initialization

register_worker

Methods

register_trigger

register_function

trigger

register_trigger_type

unregister_trigger_type

connect_async

get_connection_state

Example

shutdown

Example

shutdown_async

Example

trigger_async

Types

iii

EnqueueResult

InitOptions

MiddlewareFunctionInput

StreamRequest

StreamResponse

TelemetryOptions

TriggerAction

TriggerActionEnqueue

iii.channel

Channel

ChannelReader

ChannelWriter

StreamChannelRef

iii.engine

EngineFunctions

EngineTriggers

iii.errors

InvocationError

iii.protocol

MessageType

RegisterFunctionFormat

RegisterFunctionInput

RegisterFunctionMessage

RegisterTriggerInput

RegisterTriggerMessage

RegisterTriggerTypeInput

RegisterTriggerTypeMessage

TriggerRequest

iii.runtime

FunctionRef

TriggerTypeRef

iii.state

IState

StateDeleteInput

StateDeleteResult

StateEventData

StateEventType

StateGetInput

StateListInput

StateSetInput

StateSetResult

StateUpdateInput

StateUpdateResult

iii.stream

IStream

StreamDeleteInput

StreamDeleteResult

StreamGetInput

StreamListGroupsInput

StreamListInput

StreamSetInput

StreamSetResult

StreamUpdateInput

StreamUpdateResult

iii.trigger

Trigger

TriggerActionVoid

TriggerConfig

TriggerHandler