Method execute

src/tools/filesystem/csv.ts:131–184

(args: z.infer<typeof CsvReadArgs>, _ctx: ToolContext)

  argsSchema = CsvReadArgs;

  async execute(args: z.infer<typeof CsvReadArgs>, _ctx: ToolContext): Promise<ToolResult> {
    try {
      const text = await fs.readFile(args.path, 'utf-8');
      // Sniff delimiter from first line if not given
      const firstNL = text.search(/[\r\n]/);
      const headerLine = firstNL === -1 ? text : text.slice(0, firstNL);
      const delim = args.delimiter ?? detectDelimiter(headerLine);

      const allRows = parseCSV(text, delim);
      if (allRows.length === 0) return { content: `[CSV_EMPTY] ${args.path} has no rows.` };

      const hasHeader = args.has_header !== false;
      const headers = hasHeader ? allRows[0]! : allRows[0]!.map((_, i) => `col${i}`);
      const dataRows = hasHeader ? allRows.slice(1) : allRows;

      const startRow = args.start_row ?? 0;
      const maxRows = args.max_rows ?? 100;
      const slice = dataRows.slice(startRow, startRow + maxRows);

      // Column filter
      let cols = headers;
      let colIndices = headers.map((_, i) => i);
      if (args.columns && args.columns.length > 0) {
        const wanted = new Set(args.columns);
        colIndices = headers.map((h, i) => wanted.has(h) ? i : -1).filter(i => i !== -1);
        cols = colIndices.map(i => headers[i]!);
      }

      // Build records
      const records = slice.map(r => {
        const obj: Record<string, string> = {};
        for (let j = 0; j < cols.length; j++) {
          obj[cols[j]!] = r[colIndices[j]!] ?? '';
        }
        return obj;
      });

      const lines: string[] = [];
      lines.push(`CSV: ${args.path}`);
      lines.push(`Delimiter: ${delim === '\t' ? '\\t (tab)' : delim}`);
      lines.push(`Total rows: ${dataRows.length}${args.max_rows && dataRows.length > args.max_rows ? ' (showing first ' + maxRows + ')' : ''}`);
      lines.push(`Columns (${headers.length}): ${headers.join(', ')}`);
      if (args.columns) lines.push(`Filtered to: ${cols.join(', ')}`);
      lines.push('');
      lines.push(`Rows ${startRow + 1}-${startRow + slice.length}:`);
      lines.push(JSON.stringify(records, null, 2));
      return {
        content: lines.join('\n'),
        metadata: { totalRows: dataRows.length, returnedRows: slice.length, columns: headers, delimiter: delim },
      };
    } catch (e: any) {
      return { content: `[CSV_ERROR] ${e?.message ?? String(e)}`, isError: true };
    }
  }
}

const CsvWriteArgs = z.object({