@hashgraphonline/hedera-agent-kit/src/langchain/tools/scs/get-contract-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 {
  BaseHederaQueryTool,
  BaseHederaQueryToolParams,
  FieldProcessor,
} from '../common/base-hedera-query-tool';

const GetContractZodSchema = z.object({
  contractIdOrAddress: z.string().describe('The contract ID or EVM address'),
  timestamp: z
    .string()
    .optional()
    .describe('Optional timestamp for historical data'),
  includeBytecode: z
    .boolean()
    .optional()
    .default(false)
    .describe(
      'Whether to include full bytecode in response (may be very large)'
    ),
});

/**
 * Tool for retrieving a specific contract by ID or address.
 */
export class HederaGetContractTool extends BaseHederaQueryTool<
  typeof GetContractZodSchema
> {
  name = 'hedera-get-contract';
  description =
    'Retrieves a specific contract by ID or EVM address from the Hedera network. Use includeBytecode=true for full bytecode (may be large).';
  specificInputSchema = GetContractZodSchema;
  namespace = 'scs';

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

  protected override getLargeFieldProcessors(
    args: z.infer<typeof GetContractZodSchema>
  ): Record<string, FieldProcessor> {
    if (args.includeBytecode) {
      return {};
    }

    return {
      'contract.bytecode': {
        maxLength: 200,
        truncateMessage: '[Use includeBytecode=true for full bytecode]',
      },
      'contract.runtime_bytecode': {
        maxLength: 200,
        truncateMessage: '[Use includeBytecode=true for full runtime bytecode]',
      },
      'contract.creation_bytecode': {
        maxLength: 200,
        truncateMessage:
          '[Use includeBytecode=true for full creation bytecode]',
      },
      bytecode: {
        maxLength: 200,
        truncateMessage: '[Use includeBytecode=true for full bytecode]',
      },
      runtime_bytecode: {
        maxLength: 200,
        truncateMessage: '[Use includeBytecode=true for full runtime bytecode]',
      },
      creation_bytecode: {
        maxLength: 200,
        truncateMessage:
          '[Use includeBytecode=true for full creation bytecode]',
      },
    };
  }

  protected async executeQuery(
    args: z.infer<typeof GetContractZodSchema>
  ): Promise<unknown> {
    this.logger.info(`Getting contract: ${args.contractIdOrAddress}`);

    const contract = await this.hederaKit
      .query()
      .getContract(args.contractIdOrAddress, args.timestamp);

    if (contract === null) {
      return {
        success: false,
        error: `Contract ${args.contractIdOrAddress} not found`,
      };
    }

    return {
      success: true,
      contract,
      summary: {
        contractId: contract.contract_id,
        evmAddress: contract.evm_address,
        created: contract.created_timestamp,
        expiration: contract.expiration_timestamp,
        deleted: contract.deleted,
        memo: contract.memo || 'No memo',
        autoRenewPeriod: contract.auto_renew_period,
        maxAutomaticTokenAssociations:
          contract.max_automatic_token_associations,
        hasAdminKey: Boolean(contract.admin_key),
        hasBytecode: Boolean(contract.bytecode),
        hasRuntimeBytecode: Boolean(contract.runtime_bytecode),
        bytecodeIncluded: args.includeBytecode,
      },
    };
  }
}