Senior Agentic AI and Harness Engineer

Location: Sofia, Bulgaria

Time Type: Full time

Job Description

HS Financial Technologies (HSFT) is a global technology and fund administration partner to alternative asset managers, supporting more than $900 billion in assets under administration. We serve private equity, private credit, hedge funds, endowments, and others with integrated technology, specialized expertise, and scalable operations.

Our proprietary platform connects data, workflows, and operations across the investment lifecycle, delivering the automation, transparency, and insights clients need to operate efficiently and grow with confidence. Combined with deep expertise across fund accounting, middle office, investor services, regulatory reporting, tax, risk, and front-office solutions, we help clients navigate complexity at scale.

More than 2,400 professionals across 14 global offices deliver the expertise, responsiveness, and consistency that have made HSFT a trusted partner to alternative asset managers worldwide.

At HSFT, we are committed to helping employees build meaningful, long-term careers through structured development programs, leadership opportunities, and clear paths for growth. Guided by our core values of Relationships, Support, Innovation, and Expertise, we foster a collaborative environment where people are empowered to learn, contribute, and succeed.

We offer flexible working arrangements, comprehensive health and well-being benefits, and a culture that invests in our people because they are the foundation of our success.

Founded in 2008 as HedgeServ, HSFT is recognized as a leading provider of alternative asset services, earning industry recognition across technology, accounting, client service, investor services, and regulatory expertise.

Department Overview

The AI Engineering team builds secure, reliable, and reusable AI capabilities for HS Financial Technologies' business and technology platforms, partnering across engineering, security, data, and operations to move solutions into production.

We integrate AI into existing workflows and platforms, focusing on measurable outcomes, production discipline, responsible AI, security, human oversight, and evidence-based evaluation.

Role Overview

You will design, build, and operate production AI agents for financial operations and enterprise workflows. In this role, the AI harness is the production layer around the model: the agent runtime, orchestration, controls, evaluation, and observability. You will help shape and evolve this layer, including retrieval, memory, tool execution, workflow state, human approvals, and safety controls.

You will bring software engineering expertise, hands-on production LLM experience, sound architectural judgment, effective troubleshooting skills, and a collaborative approach to working across teams. You will also contribute to establishing reusable patterns and standards for HS Financial Technologies engineering teams.

Key Responsibilities

Runtime

• Design, deploy, and support reliable production runtimes for AI agents serving financial operations and enterprise workflows.

Orchestration

• Build and extend agent loops, including context assembly, retrieval, memory, tool selection, execution limits, workflow state, and response validation.

Controls

• Implement authorization, human approvals, policy checks, validation, checkpoints, idempotency, retries, and exception handling throughout agent workflows.

Enterprise Integration

• Build validated and auditable tool and system interfaces with least-privilege permissions, prompt-injection defenses, and controls outside the model that isolate reasoning from deterministic execution.

Evaluation

• Build repeatable tests and regression suites for agent outcomes, supporting evidence, and tool-execution paths; diagnose quality, safety, failures, latency, and cost.

Observability

• Monitor and troubleshoot production agents, maintain audit evidence, and translate operational findings into reusable engineering standards and best practices.

Required Qualifications

• Bachelor's degree in Computer Science, Engineering, Information Technology, or a related technical field, or equivalent practical experience.
• Demonstrated software engineering experience, typically gained over 5+ years, including experience delivering LLM- or agent-based applications in production environments.
• Proven experience with Python, API design, asynchronous processing, automated testing, source control, and AWS engineering; experience with a managed model platform such as Amazon Bedrock or an equivalent service.
• Hands-on experience implementing agent loops, context assembly, retrieval, memory, tool selection and limits, durable state, checkpoints, retries, and idempotency.
• Experience building regression evaluations for outcomes, supporting evidence, and tool-execution paths, along with implementing secure access controls, prompt-injection defenses, and deterministic operational safeguards.
• Demonstrated troubleshooting, analytical, communication, and cross-functional collaboration skills.

Preferred Experience

• Experience in financial services or another regulated or highly controlled environment.
• Experience with model or tool gateways and interoperability protocols, such as MCP, as well as multi-agent systems and durable workflow engines.
• Knowledge of secure tool execution, containers, infrastructure as code, CI/CD, and observability platforms.
• Familiarity with responsible AI practices, governance frameworks, model risk management, and regulatory controls.
• Experience contributing to shared AI platforms, mentoring engineers, or establishing reusable engineering standards.
• Relevant certifications in AWS, cloud engineering, AI, security, or data are valued but not required.

Benefits

• Attractive compensation package including extensive set of benefits, such as platinum health insurance, sport membership, food vouchers, employee assistance program, etc.
• 25 vacation days per year.
• Additional vacation days with 1 added for every year in the company (up to 3 additional days).
• Flexibility in working hours and locations (WFH available).
• Professional environment with great development opportunities.
• Тuition reimbursement program (personal budget up to 1000 EUR).
• Enjoy a start-up like environment on the back of a well-established and profitable company.
• Work in a culture that rewards results.
• Be free to make many of your own decisions.

HS Financial Technologies is committed to fostering an inclusive workplace where everyone can thrive. We encourage applications from qualified candidates of all backgrounds, experiences, and perspectives. If you require a reasonable accommodation during any stage of the recruitment process, please let us know.