Add native LLM core foundation (#24712)

2026-05-08 16:56:20 -04:00
parent dc7d665e94
commit 5bb7b23440
144 changed files with 17052 additions and 2 deletions
@@ -0,0 +1,196 @@
+import { Effect } from "effect"
+import { LLMError, type ProviderMetadata, type ToolCall, type ToolInputDelta } from "../../schema"
+import { eventError, parseToolInput, type ToolAccumulator } from "../shared"
+
+type StreamKey = string | number
+
+/**
+ * One pending streamed tool call. Providers emit the tool identity and JSON
+ * argument text across separate chunks; `input` is the raw JSON string collected
+ * so far, not the parsed object.
+ */
+export interface PendingTool extends ToolAccumulator {
+  readonly providerExecuted?: boolean
+  readonly providerMetadata?: ProviderMetadata
+}
+
+/**
+ * Sparse parser state keyed by the provider's stream-local tool identifier.
+ *
+ * This key is not the final tool-call id (`call_...`). It is the id/index the
+ * provider uses while streaming a partial call: OpenAI Chat / Anthropic /
+ * Bedrock use numeric content indexes, while OpenAI Responses uses string
+ * `item_id`s. The generic keeps each protocol internally consistent.
+ */
+export type State<K extends StreamKey> = Partial<Record<K, PendingTool>>
+
+/**
+ * Result of adding argument text to one pending tool call. It returns both the
+ * next `tools` state and the updated `tool` because parsers often need the
+ * current id/name immediately. `event` is present only when new text arrived;
+ * metadata-only deltas update identity without emitting `tool-input-delta`.
+ */
+export interface AppendOutcome<K extends StreamKey> {
+  readonly tools: State<K>
+  readonly tool: PendingTool
+  readonly event?: ToolInputDelta
+}
+
+/** Create empty accumulator state for one provider stream. */
+export const empty = <K extends StreamKey>(): State<K> => ({})
+
+const withTool = <K extends StreamKey>(tools: State<K>, key: K, tool: PendingTool): State<K> => {
+  return { ...tools, [key]: tool }
+}
+
+const withoutTool = <K extends StreamKey>(tools: State<K>, key: K): State<K> => {
+  const next = { ...tools }
+  delete next[key]
+  return next
+}
+
+const inputDelta = (tool: PendingTool, text: string): ToolInputDelta => ({
+  type: "tool-input-delta",
+  id: tool.id,
+  name: tool.name,
+  text,
+  ...(tool.providerMetadata ? { providerMetadata: tool.providerMetadata } : {}),
+})
+
+const toolCall = (route: string, tool: PendingTool, inputOverride?: string) =>
+  parseToolInput(route, tool.name, inputOverride ?? tool.input).pipe(
+    Effect.map(
+      (input): ToolCall =>
+        tool.providerExecuted
+          ? {
+              type: "tool-call",
+              id: tool.id,
+              name: tool.name,
+              input,
+              providerExecuted: true,
+              ...(tool.providerMetadata ? { providerMetadata: tool.providerMetadata } : {}),
+            }
+          : {
+              type: "tool-call",
+              id: tool.id,
+              name: tool.name,
+              input,
+              ...(tool.providerMetadata ? { providerMetadata: tool.providerMetadata } : {}),
+            },
+    ),
+  )
+
+/** Store the updated tool and produce the optional public delta event. */
+const appendTool = <K extends StreamKey>(
+  tools: State<K>,
+  key: K,
+  tool: PendingTool,
+  text: string,
+): AppendOutcome<K> => ({
+  tools: withTool(tools, key, tool),
+  tool,
+  event: text.length === 0 ? undefined : inputDelta(tool, text),
+})
+
+export const isError = <K extends StreamKey>(result: AppendOutcome<K> | LLMError): result is LLMError =>
+  result instanceof LLMError
+
+/**
+ * Register a tool call whose start event arrived before any argument deltas.
+ * Used by Anthropic `content_block_start`, Bedrock `contentBlockStart`, and
+ * OpenAI Responses `response.output_item.added`.
+ */
+export const start = <K extends StreamKey>(
+  tools: State<K>,
+  key: K,
+  tool: Omit<PendingTool, "input"> & { readonly input?: string },
+) => withTool(tools, key, { ...tool, input: tool.input ?? "" })
+
+/**
+ * Append a streamed argument delta, starting the tool if this provider encodes
+ * identity on the first delta instead of a separate start event. OpenAI Chat has
+ * this shape: `tool_calls[].index` is the stream key, and `id` / `name` may only
+ * appear on the first delta for that index.
+ */
+export const appendOrStart = <K extends StreamKey>(
+  route: string,
+  tools: State<K>,
+  key: K,
+  delta: { readonly id?: string; readonly name?: string; readonly text: string },
+  missingToolMessage: string,
+): AppendOutcome<K> | LLMError => {
+  const current = tools[key]
+  const id = delta.id ?? current?.id
+  const name = delta.name ?? current?.name
+  if (!id || !name) return eventError(route, missingToolMessage)
+
+  const tool = {
+    id,
+    name,
+    input: `${current?.input ?? ""}${delta.text}`,
+    providerExecuted: current?.providerExecuted,
+    providerMetadata: current?.providerMetadata,
+  }
+  if (current && delta.text.length === 0 && current.id === id && current.name === name) return { tools, tool: current }
+  return appendTool(tools, key, tool, delta.text)
+}
+
+/**
+ * Append argument text to a tool that must already have been started. This keeps
+ * protocols honest when their stream grammar promises a start event before any
+ * argument delta.
+ */
+export const appendExisting = <K extends StreamKey>(
+  route: string,
+  tools: State<K>,
+  key: K,
+  text: string,
+  missingToolMessage: string,
+): AppendOutcome<K> | LLMError => {
+  const current = tools[key]
+  if (!current) return eventError(route, missingToolMessage)
+  if (text.length === 0) return { tools, tool: current }
+  return appendTool(tools, key, { ...current, input: `${current.input}${text}` }, text)
+}
+
+/**
+ * Finalize one pending tool call: parse the accumulated raw JSON, remove it
+ * from state, and return the optional public `tool-call` event. Missing keys are
+ * a no-op because some providers emit stop events for non-tool content blocks.
+ */
+export const finish = <K extends StreamKey>(route: string, tools: State<K>, key: K) =>
+  Effect.gen(function* () {
+    const tool = tools[key]
+    if (!tool) return { tools }
+    return { tools: withoutTool(tools, key), event: yield* toolCall(route, tool) }
+  })
+
+/**
+ * Finalize one pending tool call with an authoritative final input string.
+ * OpenAI Responses can send accumulated deltas and then repeat the completed
+ * arguments on `response.output_item.done`; the final value wins.
+ */
+export const finishWithInput = <K extends StreamKey>(route: string, tools: State<K>, key: K, input: string) =>
+  Effect.gen(function* () {
+    const tool = tools[key]
+    if (!tool) return { tools }
+    return { tools: withoutTool(tools, key), event: yield* toolCall(route, tool, input) }
+  })
+
+/**
+ * Finalize every pending tool call at once. OpenAI Chat has this shape: it does
+ * not emit per-tool stop events, so all accumulated calls finish when the choice
+ * receives a terminal `finish_reason`.
+ */
+export const finishAll = <K extends StreamKey>(route: string, tools: State<K>) =>
+  Effect.gen(function* () {
+    const pending = Object.values<PendingTool | undefined>(tools).filter(
+      (tool): tool is PendingTool => tool !== undefined,
+    )
+    return {
+      tools: empty<K>(),
+      events: yield* Effect.forEach(pending, (tool) => toolCall(route, tool)),
+    }
+  })
+
+export * as ToolStream from "./tool-stream"