We are looking for an experienced Senior Prompt Engineer to help design and improve the behaviour of AI agents within an internal AI platform. The role focuses on prompt development and optimization, agent configuration, systematic evaluation and measurable improvement of LLM applications, including a conversational AI assistant for end customers.

• Design, maintain and improve system prompts, agent instructions and reusable prompt components.
• Define routing and handover between agents.
• Define how agents use knowledge sources (retrieval) and tools (tool calling).
• Configure agent behaviour when information is missing or a request exceeds the agent’s capabilities.
• Define language, tone and structured output formats (JSON schemas).
• Ensure reliable agent behaviour, including factual grounding, appropriate tool usage, language consistency and handling of ambiguous requests.
• Prepare and document prompt changes and create representative evaluation datasets.
• Define scoring criteria and compare results to demonstrate the impact of changes.
• Investigate failures using conversation traces and evaluation results.
• Develop regression test cases and assess how prompt or model changes affect response quality.
• Collaborate with platform engineers, evaluation specialists, product teams and domain experts.

• Hands-on experience developing prompts for LLM applications
• Experience configuring AI agents and systematically evaluating their behaviour beyond individual examples
• Knowledge of system instructions, context management and few-shot examples
• Experience with tool calling, retrieval and structured outputs, including JSON schemas
• Ability to inspect API requests, tool results and conversation traces
• Ability to document reproducible experiments
• Professional working English

Nice to have:

• Python scripting
• Git
• Experience with automated evaluation frameworks and LLM judges
• Experience with LangChain, LangGraph or comparable agent frameworks
• Experience in regulated or enterprise environments
• Experience testing multilingual applications

• We are a reliable and stable company with an international reach
• If a project ends, we immediately offer another one
• We have projects from more than 200 different companies
• We guarantee timely invoice payments and minimal administration
• We organize great company events for our entire IT community
• We provide free accounting and tax consulting
• We pride ourselves on a personal approach and fairness, you can rely on us