AI Agent & Tool-Use Engineer (RE2)

Barcelona Supercomputing Center; Barcelona; On-site; EUR 73,000 - 95,000; Full time

Benefits offered by this job

Restaurant tickets

Private health insurance

Relocation support

Flexible working hours

Job summary

The Barcelona Supercomputing Center (BSC-CNS) invites applications for an AI Agent & Tool-Use Engineer (RE2) to advance agentic workflows, multi-step reasoning, and tool integration within a premier HPC environment in Barcelona.

You will collaborate with the Language Modeling Team on fine-tuning and post-training of large language models, explore Model Context Protocol interfaces, and build evaluation pipelines for reliable model-tool interactions.

Qualifications

• The candidate should have strong experience in fine-tuning and post-training of large language models.
• Hands-on experience with agentic AI patterns and tool-use integration.
• Proficiency in Python and deep learning frameworks such as PyTorch.
• Experience with post-training frameworks like TRL, FastChat, NeMo-RL.

Responsibilities

• Implement and test agentic workflows including multi-step reasoning and tool-use capabilities under supervision.
• Develop and refine Function Calling interfaces and connectors using MCP to enhance model interactivity.
• Execute post-training experiments to improve agentic performance of models.
• Build and maintain evaluation pipelines for model-tool interactions.
• Collaborate with the data team to curate instruction datasets for task-oriented dialogue.

Skills

Fine-tuning LLMs

Post-training LLMs

Agentic AI patterns

Python

PyTorch

MCP API integration

Model Context Protocol

English proficiency

Spanish knowledge

Education

Degree in Computer Science, Mathematics or related

Tools

TRL

FastChat

NeMo-RL

Job description

Job Title

AI Agent & Tool-Use Engineer (RE2)

Closing Date

Thursday, 22 October, 2026

About BSC

The Barcelona Supercomputing Center - Centro Nacional de Supercomputación (BSC-CNS) is the leading supercomputing center in Spain. It houses MareNostrum, one of the most powerful supercomputers in Europe, was a founding and hosting member of the former European HPC infrastructure PRACE (Partnership for Advanced Computing in Europe), and is now hosting entity for EuroHPC JU, the Joint Undertaking that leads large-scale investments and HPC provision in Europe. The mission of BSC is to research, develop and manage information technologies in order to facilitate scientific progress. BSC combines HPC service provision and R&D into both computer and computational science (life, earth and engineering sciences) under one roof, and currently has over 1000 staff from 60 countries.

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Let's stay connected with BSC Folks!

We are particularly interested for this role in the strengths and lived experiences of women and underrepresented groups to help us avoid perpetuating biases and oversights in science and IT research. In instances of equal merit, the incorporation of the under-represented sex will be favoured.

We promote Equity, Diversity and Inclusion, fostering an environment where each and every one of us is appreciated for who we are, regardless of our differences.

If you consider that you do not meet all the requirements, we encourage you to continue applying for the job offer. We value diversity of experiences and skills, and you could bring unique perspectives to our team.

Context And Mission

The Language Modeling Team at the AI Institute hosted at BSC has consolidated experience across several core NLP and AI areas, including massive language model training, fine-tuning, post-training alignment, domain adaptation, AI agent development and unsupervised learning, including low-resource languages. It has been entrusted by the Spanish and Catalan governments with the mission to develop foundational open-source resources and technologies for Spanish, Catalan and other co-official languages. In addition, the team actively participates in various EU-funded international research initiatives. In this context, the AI Institute is looking for talent to help advance its operations, research capabilities and technical infrastructure.

The Language Modeling Team is seeking candidates with a strong background in computational linguistics and hands-on experience in Language Technologies; particularly in deep learning, large language model development, instruction tuning, and agentic workflows, as well as related areas of Natural Language and Speech Processing.

The successful candidate will work in a highly sophisticated HPC environment, access state-of-the-art computational infrastructure, and collaborate with leading experts both locally and internationally. The researcher will be responsible for designing and implementing innovative techniques for language modeling, evaluation and system adaptation tailored to high-performance computing systems.

Key Duties

• Implement and test agentic workflows including multi-step reasoning and tool-use capabilities under the supervision of the senior architect.
• Develop and refine Function Calling interfaces and connectors using the Model Context Protocol (MCP) to enhance model interactivity.
• Execute post-training experiments using TRL, FastChat, and NeMo-RL to improve the agentic performance of small and large models.
• Build and maintain evaluation pipelines specifically designed to measure the reliability and safety of model-tool interactions.
• Collaborate with the data team to curate high-quality instruction datasets for task-oriented dialogue and function execution.

Requirements

Education

• Degree in Computer Science, Mathematics or related.

Essential Knowledge and Professional Experience

• Solid experience in Fine-tuning and Post-training of Large Language Models.
• Practical experience with Agentic AI patterns such as ReAct or autonomous tool-use.
• Proficiency in Python and Deep Learning libraries like PyTorch.
• Hands-on experience with modern post-training frameworks including TRL, FastChat, or NeMo-RL.
• Excellent level of written and spoken English.

Additional Knowledge and Professional Experience

• Familiarity with Model Context Protocol (MCP) and API integration for LLMs.
• Knowledge of advanced preference alignment methods like DPO, GSPO, or CISPO.
• Experience in developing benchmarking tools for function calling and reasoning.
• Fluency in Spanish is highly valued.
• Knowledge of Spain's co-official languages is a significant advantage.

Competences

• Strong technical execution skills with a focus on reproducibility and clean code.
• Ability to work effectively in a team-oriented research environment.
• Proactive problem-solving mindset when dealing with complex system integrations.
• Detail-oriented approach to evaluating model reliability and edge cases.

Conditions

• The position will be located at BSC within the Directors Department
• We offer a full-time contract (35h/week), a good working environment, a highly stimulating environment with state-of-the-art infrastructure, flexible working hours, extensive training plan, restaurant tickets, private health insurance, support to the relocation procedures
• Duration: Open-ended contract due to technical and scientific activities linked to the project and budget duration
• Holidays: 22 days of holidays + 6 personal days + 24th and 31st of December per our collective agreement
• Salary: we offer a competitive salary commensurate with the qualifications and experience of the candidate and according to the cost of living in Barcelona
• Starting date: ASAP