@langchain/langgraph-sdk/dist/stream/tool-calls.js

Client library for interacting with the LangGraph API

import { parseToolOutput } from "../client/stream/handles/tools.js";
import { ToolMessage } from "@langchain/core/messages";
//#region src/stream/tool-calls.ts
/**
* Insert or replace an assembled tool call by call id.
*
* ToolCallAssembler mutates its active handle in place as `tool-finished` /
* `tool-error` events arrive. Publish a fresh object here so framework
* adapters that pass individual tool calls as props (notably Vue's shallow
* prop tracking) observe status/output changes.
*/
function upsertToolCall(current, next) {
	const snapshot = { ...next };
	const idx = current.findIndex((toolCall) => toolCall.callId === next.callId);
	if (idx < 0) return [...current, snapshot];
	const updated = current.slice();
	updated[idx] = snapshot;
	return updated;
}
/**
* Backfill unfinished tool-call handles from authoritative ToolMessages in a
* values snapshot. This covers headless tools whose graph state contains the
* result even when the `tools` channel omits a matching `tool-finished` event.
*/
function reconcileToolCallsFromMessages(toolCalls, messages) {
	let updated;
	for (const message of messages) {
		if (!ToolMessage.isInstance(message)) continue;
		const callId = message.tool_call_id;
		if (typeof callId !== "string" || callId.length === 0) continue;
		const currentToolCalls = updated ?? toolCalls;
		const idx = currentToolCalls.findIndex((toolCall) => toolCall.callId === callId);
		if (idx < 0) continue;
		const current = currentToolCalls[idx];
		if (current.status === "finished" && current.output != null) continue;
		const output = parseToolOutput(message.content);
		if (output == null) continue;
		updated = upsertToolCall(currentToolCalls, {
			...current,
			output,
			status: "finished",
			error: void 0
		});
	}
	return updated ?? toolCalls;
}
/**
* Build completed scoped tool-call handles from an authoritative
* `values.messages` snapshot. Used when an idle thread hydrates card panels
* from checkpoint history instead of replaying scoped `/events`.
*/
function seedToolCallsFromMessages(namespace, messages) {
	let toolCalls = [];
	for (const message of messages) {
		const raw = message.tool_calls;
		if (!Array.isArray(raw)) continue;
		for (const toolCall of raw) {
			if (toolCall == null || typeof toolCall !== "object") continue;
			const record = toolCall;
			if (typeof record.id !== "string" || record.id.length === 0) continue;
			if (typeof record.name !== "string" || record.name.length === 0) continue;
			if (namespace.length > 0 && record.name === "task") continue;
			toolCalls = upsertToolCall(toolCalls, {
				id: record.id,
				callId: record.id,
				name: record.name,
				namespace: [...namespace, `tools:${record.id}`],
				input: record.args ?? {},
				args: record.args ?? {},
				output: null,
				status: "running",
				error: void 0
			});
		}
	}
	return reconcileToolCallsFromMessages(toolCalls, messages);
}
//#endregion
export { reconcileToolCallsFromMessages, seedToolCallsFromMessages, upsertToolCall };

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