@hashgraphonline/hedera-agent-kit/src/langchain/tools/hcs/submit-message-tool.ts

Build LLM-powered applications that interact with the Hedera Network. Create conversational agents that can understand user requests in natural language and execute Hedera transactions, or build backend systems that leverage AI for on-chain operations.

import { z } from 'zod';
import { SubmitMessageParams } from '../../../types';
import {
  BaseHederaTransactionTool,
  BaseHederaTransactionToolParams,
} from '../common/base-hedera-transaction-tool';
import { HcsBuilder } from '../../../builders/hcs/hcs-builder';
import { BaseServiceBuilder } from '../../../builders/base-service-builder';

const SubmitMessageZodSchemaCore = z.object({
  topicId: z.string().describe('The ID of the topic (e.g., "0.0.xxxx").'),
  message: z
    .string()
    .describe(
      'The message content. For binary data, provide as a base64 encoded string; the builder handles decoding.'
    ),
  maxChunks: z
    .number()
    .int()
    .positive()
    .optional()
    .describe(
      'Optional. Maximum number of chunks for messages exceeding single transaction limits. Builder handles chunking.'
    ),
  chunkSize: z
    .number()
    .int()
    .positive()
    .optional()
    .describe(
      'Optional. Size of each chunk in bytes if chunking is performed. Builder applies default if needed.'
    ),
  submitKey: z
    .string()
    .optional()
    .describe(
      'Optional. Submit key if required by the topic and different from the operator (e.g., serialized public key string, or private key string for derivation by builder).'
    ),
});

export class HederaSubmitMessageTool extends BaseHederaTransactionTool<
  typeof SubmitMessageZodSchemaCore
> {
  name = 'hedera-hcs-submit-message';
  description =
    'Submits a message to a Hedera Consensus Service (HCS) topic. The builder handles chunking and base64 decoding for binary messages.';
  specificInputSchema = SubmitMessageZodSchemaCore;
  namespace = 'hcs';

  constructor(params: BaseHederaTransactionToolParams) {
    super(params);
  }

  protected getServiceBuilder(): BaseServiceBuilder {
    return this.hederaKit.hcs();
  }

  protected async callBuilderMethod(
    builder: BaseServiceBuilder,
    specificArgs: z.infer<typeof SubmitMessageZodSchemaCore>
  ): Promise<void> {
    await (builder as HcsBuilder).submitMessageToTopic(
      specificArgs as unknown as SubmitMessageParams
    );
  }
}