Agentic AI & LLM Applications Software Development Engineer, Senior

Agentic AI & LLM Applications Software Development Engineer, Senior The Opportunity: To achieve an organization’s mission, leaders need strong team members who can build the next generation of agentic AI to transform how clients accelerate research, makes decisions, and ships products at scale. That is why we need you, an experienced Software Development Engineer who can operate at a system-of-systems level to support clients in advancing AI-enabled systems within an R&D environment. As part of our team, you'll serve as a Software Development Engineer to the Advanced Research Projects Agency for Health (ARPA-H). ARPA-H has a small team that is building the next generation of agentic AI to transform how the agency accelerates research, makes decisions, and ships products at scale. The team will evolve ARPA-H's production AI assistant into an ecosystem of autonomous, multi-agent systems. You'll serve as a Software Development Engineer at the application layer to design and build agentic workflows, build LLM integrations, support tool-calling systems, and develop AI-powered features that users interact with every day. Your focus will be on what runs on top of the platform: the agents, the orchestration, the prompts, the pipelines, and the product. Your attention to detail, flexibility, communication skills, understanding of the client's mission, and problem-solving will enable the mission's success. What You’ll Work On Support agentic AI systems and orchestration, LLM application development, features and products, observability and reliability, and engineering excellence Design and build core agentic workflows: multi-step reasoning, planning, memory, and tool-use across single and multi-agent systems Implement and evolve A2A communication patterns at the application layer, enabling agents to collaborate and hand off tasks, and build and maintain the tool-calling layer, including tool definitions, input and output schemas, error handling, retry logic, and result formatting Own the MCP client-side integration, including how agents discover, invoke, and compose tools exposed via MCP servers Design multi-agent workflows that are reliable, observable, and debuggable in production, not just in demos Own LLM orchestration at the application layer, including prompt construction, context management, model selection logic, and response parsing Build and maintain RAG features, including query formulation, result ranking, citation grounding, and hallucination mitigation; implement and iterate on prompt engineering patterns and system prompts that drive GRACE's quality and consistency across OpenAI GPT, Anthropic Claude, and Google Gemini Manage context window budgets and know when to truncate, summarize, or paginate, and build the logic that makes those decisions correctly Build evaluation pipelines for LLM quality, including grounding assessment, regression testing, safety checks, and A/B experimentation on prompt and model changes Stay sharp on token economics and write prompts and pipelines that are cost-efficient without sacrificing output quality Translate ambiguous product requirements into clear technical designs and ship them fast, build new product capabilities end-to-end, including from backend application logic through to the API contract the frontend consumes, and rapidly prototype new agentic features, run experiments, collect data, and iterate based on real user behavior Collaborate closely with product, UX, applied science, and operations, write tests, handle edge cases, and make sure features degrade gracefully when upstream dependencies fail Instrument agentic workflows with tracing, logging, and metrics so failures are diagnosable and regressions are caught before users report them Define and monitor application-level SLOs: tool call success rates, response quality, and latency from the user's perspective, build fallback and guardrail logic for AI services, including what happens when a model returns something unsafe, off-topic, or structurally wrong, and work closely with the infra engineer to understand system-level constraints and design application behavior that respects them Write production-quality code: readable, tested, reviewed, and documented Communicate technical decisions clearly to both engineers and non-engineers; no one should have to guess what you decided or why, participate actively in design reviews, and push back when something is over-engineered or under-specified Ensure strong privacy, security, and compliance in all application logic and data handling Join us. The world can’t wait. You have: 7+ years of experience with software engineering, including building and operating production systems Experience in high-velocity environments where you owned and shipped complex products end-to-end Experience with at least 2 backend languages, including Python Experience building and operating systems on major cloud platforms, such as AWS, GCP, or Azure Experience with containerization and working within CI/CD pipelines Knowledge of modern backend frameworks and async patterns Knowledge of algorithms, data structures, APIs, and software design patterns Bachelor's degree in Computer Science or Software Engineering Nice if you Have: Experience building production systems on top of LLMs, including tool-calling, RAG, multi-step reasoning, and context management, and multi-agent (A2A) architectures and orchestration frameworks in production, not just in prototypes Experience with MCP at the client and consumer layer and prompt engineering and LLM behavior across model families Experience building LLM evaluation and regression testing pipelines Experience in startup or early-stage environment, including 0-to-1 product building, big tech building customer-facing AI platforms or developer tools at scale, security-conscious engineering, input validation, output sanitization, audit logging, and responsible AI guardrails Experience in healthcare, life sciences, or other regulated domains Knowledge of why Claude and GPT respond differently to the same prompt, how to design for it, and how agents discover and invoke tools via MCP Knowledge of token economics: cost-per-query awareness, context budget management, and prompt efficiency Ability to be comfortable with ambiguity and a high sense of urgency Ability to be a self-starter, operate within a fast-paced environment, multi-task and handle multiple priorities Possession of excellent oral and written communication skills Compensation At Booz Allen, we celebrate your contributions, provide you with opportunities and choices, and support your total well-being. Our offerings include health, life, disability, financial, and retirement benefits, as well as paid leave, professional development, tuition assistance, work-life programs, and dependent care. Our recognition awards program acknowledges employees for exceptional performance and superior demonstration of our values. Full-time and part-time employees working at least 20 hours a week on a regular basis are eligible to participate in Booz Allen’s benefit programs. Individuals that do not meet the threshold are only eligible for select offerings, not inclusive of health benefits. We encourage you to learn more about our total benefits by visiting the Resource page on our Careers site and reviewing Our Employee Benefits page. Salary at Booz Allen is determined by various factors, including but not limited to location, the individual’s particular combination of education, knowledge, skills, competencies, and experience, as well as contract-specific affordability and organizational requirements. The projected compensation range for this position is $86,800.00 to $198,000.00 (annualized USD). The estimate displayed represents the typical salary range for this position and is just one component of Booz Allen’s total compensation package for employees. This posting will close within 90 days from the Posting Date. Identity Statement As part of the hiring process, we will ask you to complete an identity verification process that leverages advanced biometrics and artificial intelligence to ensure authenticity and protect against identity fraud. You are expected to be on camera during interviews and assessments. We reserve the right to take your picture to verify your identity and prevent fraud. 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