Class: abstract BaseEngine

Abstract base class to be extended by AI engine implementations. Provides hook orchestration, default capability flags, and optional voice-session helpers.

Examples

class MyEngine extends BaseEngine {
  public async chat(messages: ChatMessage[], options: ChatOptions) {
    // Call provider API and translate the result to ChatResult
    return provider.complete(messages, options)
  }

  public getFunctionHandlers() {
    return {}
  }

  public getInfo() {
    return { name: 'my-engine', version: '1.0.0' }
  }
}

engine.on('chat', async (ctx) => {
  return ctx.messages.filter(Boolean)
})

if (engine.supportedFeatures().voice) {
  await engine.startVoiceSession(options)
}

Remarks

Subclasses must implement BaseEngine.chat, BaseEngine.generateImage, BaseEngine.getFunctionHandlers, and BaseEngine.getInfo. Override optional voice methods when providing realtime functionality.

Constructors

new BaseEngine()

new BaseEngine(): BaseEngine

Returns

BaseEngine

Properties

Property	Modifier	Type	Description
_hooks	protected	Map<HookEvent, Hook[]>	Registered hooks keyed by event type.

Methods

callHooks()

callHooks(event, context)

callHooks(event, context): Promise<void>

Sequentially executes registered hooks for the given event while allowing each hook to mutate the message array.

Parameters

Parameter	Type	Description
event	"chat"	Hook event name.
context	ChatHookContext	Mutable hook context.

Returns

Promise<void>

Latest message array after all hooks have run.

callHooks(event, context)

callHooks(event, context): Promise<void | ChatReply>

Parameters

Parameter	Type
event	"reply"
context	ReplyHookContext

Returns

Promise<void | ChatReply>

---

chat()

abstract chat(messages, options): Promise<ChatResult>

Produces a conversational response based on supplied messages and options.

Parameters

Parameter	Type	Description
messages	ChatMessage[]	Message history presented to the engine.
options	ChatOptions	Additional configuration for the completion request.

Returns

Promise<ChatResult>

Chat response including tool calls, conversation state, and voice metadata.

---

generateImage()

abstract generateImage(options): Promise<GenerateImageResult>

Generates an image using the backing provider.

Parameters

Parameter	Type	Description
options	GenerateImageOptions	Prompt and configuration for the image request.

Returns

Promise<GenerateImageResult>

Generated images represented as base64 payloads or URLs.

---

getFunctionHandlers()

abstract getFunctionHandlers(): Record<string, Command>

Returns a mapping of function names to Robo command handlers invoked during tool execution.

Returns

Record<string, Command>

---

getInfo()

abstract getInfo(): Record<string, unknown>

Provides descriptive information about the engine for diagnostics or inspection tooling.

Returns

Record<string, unknown>

---

getMCPTools()?

optional getMCPTools(): MCPTool[]

Optionally returns MCP (Model Context Protocol) tool configurations for this engine. Engines that support MCP should override this method to return their configured MCP servers.

Returns

MCPTool[]

Array of MCP tool configurations, or empty array if MCP is not supported.

---

init()

init(): Promise<void>

Perform asynchronous initialization prior to handling requests. Override for custom setup.

Returns

Promise<void>

---

off()

off(event, hook): void

Removes a previously registered hook from the engine.

Parameters

Parameter	Type	Description
event	HookEvent	Hook event name.
hook	Hook	Hook callback to remove.

Returns

void

---

on()

on(event, hook): void

Registers a hook to run during specific engine orchestration events.

Parameters

Parameter	Type	Description
event	HookEvent	Hook event name.
hook	Hook	Hook callback to register.

Returns

void

---

startVoiceSession()

startVoiceSession(_options): Promise<VoiceSessionHandle>

Starts a realtime voice session. Engines without voice capabilities should override BaseEngine.supportedFeatures or this method to avoid throwing.

Parameters

Parameter	Type	Description
_options	VoiceSessionStartOptions	Voice session options supplied by the caller.

Returns

Promise<VoiceSessionHandle>

Throws

Always throws when not overridden by subclasses.

---

stopVoiceSession()

stopVoiceSession(_handle): Promise<void>

Stops a realtime voice session previously started by BaseEngine.startVoiceSession.

Parameters

Parameter	Type	Description
_handle	VoiceSessionHandle	Voice session handle.

Returns

Promise<void>

Throws

Always throws when voice is unsupported.

---

summarizeToolResult()?

optional summarizeToolResult(_params): Promise<object>

Optionally summarize tool execution results for provider-specific follow-up prompts.

Parameters

Parameter	Type	Description
_params	object	Details describing the tool invocation to summarize.
_params.call	ChatFunctionCall	-
_params.model?	string	-
_params.resultText	string	-
_params.success	boolean	-

Returns

Promise<object>

Summary text and an optional response identifier for traceability.

responseId

responseId: null | string;

summary

summary: string;

---

supportedFeatures()

supportedFeatures(): EngineSupportedFeatures

Returns the supported feature flags for the engine. Override to enable capabilities.

Returns

EngineSupportedFeatures