The jq Pipeline Builder Agent translates natural language data transformation requests into optimized jq filter expressions for processing JSON and NDJSON data streams. It leverages the full jq language including path expressions, recursive descent (..), reduce operators, SQL-style GROUP_BY and UNIQUE_BY, and string interpolation for template generation. The agent handles complex operations like cross-referencing multiple JSON files with input and slurp modes, building streaming parsers with –stream flag for memory-efficient processing of large files, and constructing conditional transformations with if-then-else and try-catch error handling. It generates reusable jq modules with import statements, supports custom function definitions via def, and produces shell-compatible one-liners for pipeline integration with curl, grep, and awk. Includes test case generation using jqplay-compatible formats.