ChEMBL MCP Server

Instructions

Implementation Reference

• src/index.ts:1312-1352 (handler)

  Main handler function for 'get_drug_info' tool. Validates input, fetches molecule details and drug indications from ChEMBL API, returns formatted JSON response.

  private async handleGetDrugInfo(args: any) {
    if (!isValidChemblIdArgs(args)) {
      throw new McpError(ErrorCode.InvalidParams, 'Invalid drug info arguments');
    }
  
    try {
      // Get molecule information
      const moleculeResponse = await this.apiClient.get(`/molecule/${args.chembl_id}.json`);
      const molecule = moleculeResponse.data;
  
      // Get drug indication data if available
      let indications = [];
      try {
        const indicationResponse = await this.apiClient.get('/drug_indication.json', {
          params: { molecule_chembl_id: args.chembl_id, limit: 50 },
        });
        indications = indicationResponse.data.drug_indications || [];
      } catch (e) {
        // Indications may not be available for all compounds
      }
  
      return {
        content: [
          {
            type: 'text',
            text: JSON.stringify({
              chembl_id: args.chembl_id,
              molecule_info: molecule,
              development_phase: molecule.max_phase,
              indications: indications,
            }, null, 2),
          },
        ],
      };
    } catch (error) {
      throw new McpError(
        ErrorCode.InternalError,
        `Failed to get drug info: ${error instanceof Error ? error.message : 'Unknown error'}`
      );
    }
  }

• src/index.ts:778-781 (registration)

  Registration of 'get_drug_info' tool handler in the CallToolRequestSchema switch statement.

  case 'search_drugs':
    return await this.handleSearchDrugs(args);
  case 'get_drug_info':
    return await this.handleGetDrugInfo(args);

• src/index.ts:602-610 (schema)

  Tool schema definition and registration in ListToolsRequestSchema response, including input schema requiring 'chembl_id'.

  name: 'get_drug_info',
  description: 'Get drug development status and clinical trial information',
  inputSchema: {
    type: 'object',
    properties: {
      chembl_id: { type: 'string', description: 'ChEMBL compound ID' },
    },
    required: ['chembl_id'],
  },

• src/index.ts:90-99 (helper)

  Helper validation function isValidChemblIdArgs used to validate input arguments for get_drug_info and similar tools.

  const isValidChemblIdArgs = (
    args: any
  ): args is { chembl_id: string } => {
    return (
      typeof args === 'object' &&
      args !== null &&
      typeof args.chembl_id === 'string' &&
      args.chembl_id.length > 0
    );
  };