RTSF: An open, schema-validated robot task specification format for vendor-independent description, LLM generation, and multi-platform validation of manipulator tasks

Objective: Robot task programming in manufacturing remains tightly coupled to vendor-specific languages, hindering portability and reuse. This paper presents a vendor-neutral, schema-validated format for robot task specification that enables large language model (LLM) generation and multi-robot execution without modifying the task description. Methods: The Robot Task Specification Format (RTSF) is a JSON format with nine step types covering all six control-flow constructs, governed by a JSON Schema (draft-07). A gap analysis against ten existing formats positions RTSF. Schema-guided LLM generation is evaluated on 30 task descriptions across four domains, with a prompt ablation study. A runtime architecture (recursive parser, PDDL converter, BehaviorTree.CPP converter) enables multi-backend execution. A multi-robot experiment validates six scenarios on four platforms: UR5e, Franka FR3, Kinova Gen3, and Denso Cobotta (physical robot). Results: No surveyed format combines a task-level abstraction with a formal JSON Schema, vendor-independent execution, complete control-flow coverage, and schema-guided LLM generation. The multi-robot experiment verifies identical action sequences and arguments across over 500 adapter calls on four platforms using unmodified task files. Schema-guided prompting achieves high construct recall (100% corrected validity); an independent benchmark by three external evaluators confirms generalisability. Prompt ablation confirms that disambiguation and field-name guidance rules contribute roughly equally to recall. Scalability benchmark confirms sub-second processing at 5000 steps. Conclusion: RTSF fills the gap between natural-language task descriptions and heterogeneous execution backends, enabling vendor-independent robot task programming with schema-guided LLM generation and multi-platform validation. The format, examples, scripts, and test suite (107 tests) are released under the MIT licence.