Add native LLM core foundation (#24712)

packages/llm/src/llm.ts

@@ -0,0 +1,224 @@
+import { Effect, JsonSchema, Schema } from "effect"
+import {
+  LLMClient,
+  modelLimits,
+  modelRef,
+  type ModelRefInput,
+} from "./route/client"
+import {
+  GenerationOptions,
+  HttpOptions,
+  InvalidProviderOutputReason,
+  LLMError,
+  LLMEvent,
+  LLMRequest,
+  LLMResponse,
+  Message,
+  SystemPart,
+  ToolChoice,
+  ToolDefinition,
+  type ContentPart,
+  ToolCallPart,
+  ToolResultPart,
+} from "./schema"
+import { make as makeTool, type ToolSchema } from "./tool"
+
+export type ModelInput = ModelRefInput
+
+export type MessageInput = Message.Input
+
+export type ToolChoiceInput = ToolChoice.Input
+export type ToolChoiceMode = ToolChoice.Mode
+
+export type ToolResultInput = Parameters<typeof ToolResultPart.make>[0]
+
+/** Input accepted by `LLM.request`, normalized into the canonical `LLMRequest` class. */
+export type RequestInput = Omit<
+  ConstructorParameters<typeof LLMRequest>[0],
+  "system" | "messages" | "tools" | "toolChoice" | "generation" | "http" | "providerOptions"
+> & {
+  readonly system?: string | SystemPart | ReadonlyArray<SystemPart>
+  readonly prompt?: string | ContentPart | ReadonlyArray<ContentPart>
+  readonly messages?: ReadonlyArray<Message | MessageInput>
+  readonly tools?: ReadonlyArray<ToolDefinition.Input>
+  readonly toolChoice?: ToolChoiceInput
+  readonly generation?: GenerationOptions.Input
+  readonly providerOptions?: ConstructorParameters<typeof LLMRequest>[0]["providerOptions"]
+  readonly http?: HttpOptions.Input
+}
+
+export const limits = modelLimits
+
+export const text = Message.text
+
+export const system = SystemPart.make
+
+export const message = Message.make
+
+export const user = Message.user
+
+export const assistant = Message.assistant
+
+export const model = modelRef
+
+export const toolDefinition = ToolDefinition.make
+
+export const toolCall = ToolCallPart.make
+
+export const toolResult = ToolResultPart.make
+
+export const toolMessage = Message.tool
+
+export const toolChoiceName = ToolChoice.named
+
+export const toolChoice = ToolChoice.make
+
+export const generation = GenerationOptions.make
+
+export const generate = LLMClient.generate
+
+export const stream = LLMClient.stream
+
+export const stepCountIs = LLMClient.stepCountIs
+
+export const requestInput = (input: LLMRequest): RequestInput => ({
+  ...LLMRequest.input(input),
+})
+
+export const request = (input: RequestInput) => {
+  const {
+    system: requestSystem,
+    prompt,
+    messages,
+    tools,
+    toolChoice: requestToolChoice,
+    generation: requestGeneration,
+    providerOptions: requestProviderOptions,
+    http: requestHttp,
+    ...rest
+  } = input
+  return new LLMRequest({
+    ...rest,
+    system: SystemPart.content(requestSystem),
+    messages: [...(messages?.map(message) ?? []), ...(prompt === undefined ? [] : [user(prompt)])],
+    tools: tools?.map(toolDefinition) ?? [],
+    toolChoice: requestToolChoice ? toolChoice(requestToolChoice) : undefined,
+    generation: requestGeneration === undefined ? undefined : generation(requestGeneration),
+    providerOptions: requestProviderOptions,
+    http: requestHttp === undefined ? undefined : HttpOptions.make(requestHttp),
+  })
+}
+
+export const updateRequest = (input: LLMRequest, patch: Partial<RequestInput>) =>
+  request({ ...requestInput(input), ...patch })
+
+const GENERATE_OBJECT_TOOL_NAME = "generate_object"
+
+const GENERATE_OBJECT_TOOL_DESCRIPTION = "Return the structured result by calling this tool."
+
+type GenerateObjectBase = Omit<RequestInput, "tools" | "toolChoice" | "responseFormat">
+
+export class GenerateObjectResponse<T> {
+  constructor(
+    readonly object: T,
+    readonly response: LLMResponse,
+  ) {}
+
+  get events() {
+    return this.response.events
+  }
+
+  get usage() {
+    return this.response.usage
+  }
+}
+
+export interface GenerateObjectOptions<S extends ToolSchema<any>> extends GenerateObjectBase {
+  readonly schema: S
+}
+
+export interface GenerateObjectDynamicOptions extends GenerateObjectBase {
+  /** Raw JSON Schema object describing the expected output shape. */
+  readonly jsonSchema: JsonSchema.JsonSchema
+}
+
+const runGenerateObject = Effect.fn("LLM.generateObject")(function* (
+  options: GenerateObjectBase,
+  tool: ReturnType<typeof makeTool>,
+) {
+  const baseRequest = request(options)
+  const generateRequest = LLMRequest.update(baseRequest, {
+    toolChoice: ToolChoice.named(GENERATE_OBJECT_TOOL_NAME),
+  })
+  const response = yield* LLMClient.generate({
+    request: generateRequest,
+    tools: { [GENERATE_OBJECT_TOOL_NAME]: tool },
+    toolExecution: "none",
+  })
+  const call = response.toolCalls.find(
+    (event) => LLMEvent.is.toolCall(event) && event.name === GENERATE_OBJECT_TOOL_NAME,
+  )
+  if (!call || !LLMEvent.is.toolCall(call))
+    return yield* new LLMError({
+      module: "LLM",
+      method: "generateObject",
+      reason: new InvalidProviderOutputReason({
+        message: `generateObject: model did not call the forced \`${GENERATE_OBJECT_TOOL_NAME}\` tool`,
+      }),
+    })
+  const object = yield* tool._decode(call.input).pipe(
+    Effect.mapError(
+      (error) =>
+        new LLMError({
+          module: "LLM",
+          method: "generateObject",
+          reason: new InvalidProviderOutputReason({
+            message: `generateObject: tool input failed schema decode: ${error.message}`,
+          }),
+        }),
+    ),
+  )
+  return new GenerateObjectResponse(object, response)
+})
+
+/**
+ * Run a model and decode its output against `schema`. Works on every protocol
+ * because it forces a synthetic tool call internally — provider-native JSON
+ * modes are intentionally avoided so behaviour is uniform.
+ *
+ * Two input modes:
+ *
+ * 1. `schema: EffectSchema<T>` — `.object` is decoded and typed as `T`.
+ *    Decode failures surface as `LLMError`.
+ * 2. `jsonSchema: JsonSchema.JsonSchema` — `.object` is `unknown`. Use when
+ *    the schema is only available at runtime (MCP, plugin manifests). Caller validates.
+ */
+export function generateObject<S extends ToolSchema<any>>(
+  options: GenerateObjectOptions<S>,
+): Effect.Effect<GenerateObjectResponse<Schema.Schema.Type<S>>, LLMError>
+export function generateObject(options: GenerateObjectDynamicOptions): Effect.Effect<GenerateObjectResponse<unknown>, LLMError>
+export function generateObject(
+  options: GenerateObjectOptions<ToolSchema<any>> | GenerateObjectDynamicOptions,
+) {
+  if ("schema" in options) {
+    const { schema, ...rest } = options
+    return runGenerateObject(
+      rest,
+      makeTool({
+        description: GENERATE_OBJECT_TOOL_DESCRIPTION,
+        parameters: schema,
+        success: Schema.Unknown as ToolSchema<unknown>,
+        execute: () => Effect.void,
+      }),
+    )
+  }
+  const { jsonSchema, ...rest } = options
+  return runGenerateObject(
+    rest,
+    makeTool({
+      description: GENERATE_OBJECT_TOOL_DESCRIPTION,
+      jsonSchema,
+      execute: () => Effect.void,
+    }),
+  )
+}