@langchain/core
Version:
Core LangChain.js abstractions and schemas
409 lines (408 loc) • 15 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.tool = exports.BaseToolkit = exports.DynamicStructuredTool = exports.DynamicTool = exports.Tool = exports.StructuredTool = exports.ToolInputParsingException = void 0;
const zod_1 = require("zod");
const json_schema_1 = require("@cfworker/json-schema");
const manager_js_1 = require("../callbacks/manager.cjs");
const base_js_1 = require("../language_models/base.cjs");
const config_js_1 = require("../runnables/config.cjs");
const tool_js_1 = require("../messages/tool.cjs");
const index_js_1 = require("../singletons/index.cjs");
const utils_js_1 = require("./utils.cjs");
Object.defineProperty(exports, "ToolInputParsingException", { enumerable: true, get: function () { return utils_js_1.ToolInputParsingException; } });
const is_zod_schema_js_1 = require("../utils/types/is_zod_schema.cjs");
const json_schema_js_1 = require("../utils/json_schema.cjs");
/**
* Base class for Tools that accept input of any shape defined by a Zod schema.
*/
class StructuredTool extends base_js_1.BaseLangChain {
get lc_namespace() {
return ["langchain", "tools"];
}
constructor(fields) {
super(fields ?? {});
/**
* Whether to return the tool's output directly.
*
* Setting this to true means that after the tool is called,
* an agent should stop looping.
*/
Object.defineProperty(this, "returnDirect", {
enumerable: true,
configurable: true,
writable: true,
value: false
});
Object.defineProperty(this, "verboseParsingErrors", {
enumerable: true,
configurable: true,
writable: true,
value: false
});
/**
* The tool response format.
*
* If "content" then the output of the tool is interpreted as the contents of a
* ToolMessage. If "content_and_artifact" then the output is expected to be a
* two-tuple corresponding to the (content, artifact) of a ToolMessage.
*
* @default "content"
*/
Object.defineProperty(this, "responseFormat", {
enumerable: true,
configurable: true,
writable: true,
value: "content"
});
this.verboseParsingErrors =
fields?.verboseParsingErrors ?? this.verboseParsingErrors;
this.responseFormat = fields?.responseFormat ?? this.responseFormat;
}
/**
* Invokes the tool with the provided input and configuration.
* @param input The input for the tool.
* @param config Optional configuration for the tool.
* @returns A Promise that resolves with a string.
*/
async invoke(input, config) {
let tool_call_id;
let toolInput;
let enrichedConfig = (0, config_js_1.ensureConfig)(config);
if ((0, utils_js_1._isToolCall)(input)) {
tool_call_id = input.id;
toolInput = input.args;
enrichedConfig = {
...enrichedConfig,
toolCall: input,
configurable: {
...enrichedConfig.configurable,
tool_call_id,
},
};
}
else {
toolInput = input;
}
return this.call(toolInput, enrichedConfig);
}
/**
* @deprecated Use .invoke() instead. Will be removed in 0.3.0.
*
* Calls the tool with the provided argument, configuration, and tags. It
* parses the input according to the schema, handles any errors, and
* manages callbacks.
* @param arg The input argument for the tool.
* @param configArg Optional configuration or callbacks for the tool.
* @param tags Optional tags for the tool.
* @returns A Promise that resolves with a string.
*/
async call(arg, configArg,
/** @deprecated */
tags) {
let parsed = arg;
if ((0, is_zod_schema_js_1.isZodSchema)(this.schema)) {
try {
parsed = await this.schema.parseAsync(arg);
}
catch (e) {
let message = `Received tool input did not match expected schema`;
if (this.verboseParsingErrors) {
message = `${message}\nDetails: ${e.message}`;
}
throw new utils_js_1.ToolInputParsingException(message, JSON.stringify(arg));
}
}
else {
const result = (0, json_schema_1.validate)(arg, this.schema);
if (!result.valid) {
let message = `Received tool input did not match expected schema`;
if (this.verboseParsingErrors) {
message = `${message}\nDetails: ${result.errors
.map((e) => `${e.keywordLocation}: ${e.error}`)
.join("\n")}`;
}
throw new utils_js_1.ToolInputParsingException(message, JSON.stringify(arg));
}
}
const config = (0, manager_js_1.parseCallbackConfigArg)(configArg);
const callbackManager_ = manager_js_1.CallbackManager.configure(config.callbacks, this.callbacks, config.tags || tags, this.tags, config.metadata, this.metadata, { verbose: this.verbose });
const runManager = await callbackManager_?.handleToolStart(this.toJSON(), typeof parsed === "string" ? parsed : JSON.stringify(parsed), config.runId, undefined, undefined, undefined, config.runName);
delete config.runId;
let result;
try {
result = await this._call(parsed, runManager, config);
}
catch (e) {
await runManager?.handleToolError(e);
throw e;
}
let content;
let artifact;
if (this.responseFormat === "content_and_artifact") {
if (Array.isArray(result) && result.length === 2) {
[content, artifact] = result;
}
else {
throw new Error(`Tool response format is "content_and_artifact" but the output was not a two-tuple.\nResult: ${JSON.stringify(result)}`);
}
}
else {
content = result;
}
let toolCallId;
if (config && "configurable" in config) {
toolCallId = config.configurable
.tool_call_id;
}
const formattedOutput = _formatToolOutput({
content,
artifact,
toolCallId,
name: this.name,
});
await runManager?.handleToolEnd(formattedOutput);
return formattedOutput;
}
}
exports.StructuredTool = StructuredTool;
/**
* Base class for Tools that accept input as a string.
*/
class Tool extends StructuredTool {
constructor(fields) {
super(fields);
Object.defineProperty(this, "schema", {
enumerable: true,
configurable: true,
writable: true,
value: zod_1.z
.object({ input: zod_1.z.string().optional() })
.transform((obj) => obj.input)
});
}
/**
* @deprecated Use .invoke() instead. Will be removed in 0.3.0.
*
* Calls the tool with the provided argument and callbacks. It handles
* string inputs specifically.
* @param arg The input argument for the tool, which can be a string, undefined, or an input of the tool's schema.
* @param callbacks Optional callbacks for the tool.
* @returns A Promise that resolves with a string.
*/
call(arg, callbacks) {
return super.call(typeof arg === "string" || !arg ? { input: arg } : arg, callbacks);
}
}
exports.Tool = Tool;
/**
* A tool that can be created dynamically from a function, name, and description.
*/
class DynamicTool extends Tool {
static lc_name() {
return "DynamicTool";
}
constructor(fields) {
super(fields);
Object.defineProperty(this, "name", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
Object.defineProperty(this, "description", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
Object.defineProperty(this, "func", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
this.name = fields.name;
this.description = fields.description;
this.func = fields.func;
this.returnDirect = fields.returnDirect ?? this.returnDirect;
}
/**
* @deprecated Use .invoke() instead. Will be removed in 0.3.0.
*/
async call(arg, configArg) {
const config = (0, manager_js_1.parseCallbackConfigArg)(configArg);
if (config.runName === undefined) {
config.runName = this.name;
}
return super.call(arg, config);
}
/** @ignore */
async _call(input, runManager, parentConfig) {
return this.func(input, runManager, parentConfig);
}
}
exports.DynamicTool = DynamicTool;
/**
* A tool that can be created dynamically from a function, name, and
* description, designed to work with structured data. It extends the
* StructuredTool class and overrides the _call method to execute the
* provided function when the tool is called.
*
* Schema can be passed as Zod or JSON schema. The tool will not validate
* input if JSON schema is passed.
*/
class DynamicStructuredTool extends StructuredTool {
static lc_name() {
return "DynamicStructuredTool";
}
constructor(fields) {
super(fields);
Object.defineProperty(this, "name", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
Object.defineProperty(this, "description", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
Object.defineProperty(this, "func", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
Object.defineProperty(this, "schema", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
this.name = fields.name;
this.description = fields.description;
this.func = fields.func;
this.returnDirect = fields.returnDirect ?? this.returnDirect;
this.schema = fields.schema;
}
/**
* @deprecated Use .invoke() instead. Will be removed in 0.3.0.
*/
async call(arg, configArg,
/** @deprecated */
tags) {
const config = (0, manager_js_1.parseCallbackConfigArg)(configArg);
if (config.runName === undefined) {
config.runName = this.name;
}
return super.call(arg, config, tags);
}
_call(arg, runManager, parentConfig) {
return this.func(arg, runManager, parentConfig);
}
}
exports.DynamicStructuredTool = DynamicStructuredTool;
/**
* Abstract base class for toolkits in LangChain. Toolkits are collections
* of tools that agents can use. Subclasses must implement the `tools`
* property to provide the specific tools for the toolkit.
*/
class BaseToolkit {
getTools() {
return this.tools;
}
}
exports.BaseToolkit = BaseToolkit;
function tool(func, fields) {
const isShapelessZodSchema = fields.schema &&
(0, is_zod_schema_js_1.isZodSchema)(fields.schema) &&
(!("shape" in fields.schema) || !fields.schema.shape);
const isStringJSONSchema = (0, json_schema_js_1.validatesOnlyStrings)(fields.schema);
// If the schema is not provided, or it's a shapeless schema (e.g. a ZodString), create a DynamicTool
if (!fields.schema || isShapelessZodSchema || isStringJSONSchema) {
return new DynamicTool({
...fields,
description: fields.description ??
fields.schema?.description ??
`${fields.name} tool`,
func: async (input, runManager, config) => {
return new Promise((resolve, reject) => {
const childConfig = (0, config_js_1.patchConfig)(config, {
callbacks: runManager?.getChild(),
});
void index_js_1.AsyncLocalStorageProviderSingleton.runWithConfig((0, config_js_1.pickRunnableConfigKeys)(childConfig), async () => {
try {
// TS doesn't restrict the type here based on the guard above
// eslint-disable-next-line @typescript-eslint/no-explicit-any
resolve(func(input, childConfig));
}
catch (e) {
reject(e);
}
});
});
},
});
}
const schema = fields.schema;
const description = fields.description ??
fields.schema.description ??
`${fields.name} tool`;
return new DynamicStructuredTool({
...fields,
description,
schema,
func: async (input, runManager, config) => {
return new Promise((resolve, reject) => {
const childConfig = (0, config_js_1.patchConfig)(config, {
callbacks: runManager?.getChild(),
});
void index_js_1.AsyncLocalStorageProviderSingleton.runWithConfig((0, config_js_1.pickRunnableConfigKeys)(childConfig), async () => {
try {
resolve(func(input, childConfig));
}
catch (e) {
reject(e);
}
});
});
},
});
}
exports.tool = tool;
function _formatToolOutput(params) {
const { content, artifact, toolCallId } = params;
if (toolCallId && !(0, tool_js_1.isDirectToolOutput)(content)) {
if (typeof content === "string" ||
(Array.isArray(content) &&
content.every((item) => typeof item === "object"))) {
return new tool_js_1.ToolMessage({
content,
artifact,
tool_call_id: toolCallId,
name: params.name,
});
}
else {
return new tool_js_1.ToolMessage({
content: _stringify(content),
artifact,
tool_call_id: toolCallId,
name: params.name,
});
}
}
else {
return content;
}
}
function _stringify(content) {
try {
return JSON.stringify(content, null, 2);
}
catch (_noOp) {
return `${content}`;
}
}