Mistral AI

AI

ModelBehaviorArchitect-FunctionCalling

London, United Kingdom FULL TIME Remote Friendly
Market Sentiment
HIGH DEMAND

Neural analysis suggests this role is
optimal for Senior candidates.

The Brief

“Model Behavior Architect - Function Calling at Mistral AI. Skills: Function Calling, Model Evaluation, LLM Agents. Define and measure LLM tool use. Orchestrate complex agentic workflows”

What You'll Achieve.

Define what 'good' looks like for function calling; Achieve accurate parameter selection; Ensure schema adherence; Enable multi-step tool orchestration; Improve error recovery; Enhance agentic reasoning; Produce best-in-class models

Industry & Context.

AI
Problems you'll solve

Identify and fix edge case behaviours; Address real-world constraints

What They're Looking For.

Must Have

Deep understanding of API design, structured outputs, schema specification, engineering and code behavior, LLM agents at work, reasoning, planning, multi-step tool use, Prior knowledge in training and optimising model behaviour, Expert at building robust evaluations

Nice to Have

JSON Schema

What You'll Do.

Define and measure LLM tool use

Orchestrate complex agentic workflows

Interact with models for improvement

Gather feedback on tool-calling behaviour

Design and implement evals

Create synthetic tool environments

Fix edge case behaviours

Develop evaluation pipelines

How You'll Work.

Team & Collaboration

Work hand-in-hand with our Science team; Work collaboratively with AI Scientists

Full Job Description

## Description About Mistral  At Mistral AI, we believe in the power of AI to simplify tasks, save time, and enhance learning and creativity. Our technology is designed to integrate seamlessly into daily working life.   We democratize AI through high-performance, optimized, open-source and cutting-edge models, products and solutions. Our comprehensive AI platform is designed to meet enterprise as well as personal needs. Our offerings include Le Chat, La Plateforme, Mistral Code and Mistral Compute - a suite that brings frontier intelligence to end-users.   We are a dynamic, collaborative team passionate about AI and its potential to transform society. Our diverse workforce thrives in competitive environments and is committed to driving innovation. Our teams are distributed between France, USA, UK, Germany and Singapore. We are creative, low-ego and team-spirited.   Join us to be part of a pioneering company shaping the future of AI. Together, we can make a meaningful impact. See more about our culture on https://mistral.ai/careers.   ## About the role As a Model Behavior Architect on the Function Calling team, you are at the forefront of defining and measuring how LLMs use tools, invoke functions, and orchestrate complex agentic workflows. We are looking for people who have built a career in engineering, machine learning, and large language models and are experts in model evaluation, policy writing, and creating eval pipelines for tool use and function calling. Your role is to work hand-in-hand with our Science team to define what 'good' looks like for function calling—from accurate parameter selection and schema adherence to multi-step tool orchestration, error recovery, and agentic reasoning. Join us if you are passionate about tackling cutting-edge, open-ended research challenges and transforming your insights into best-in-class models. ## What you will do Interact with models to identify where function calling and tool use behaviour can be improved Gather intern

Free ATS check

Applying for this Model Behavior Architect - Function Calling role?

Most applicants get filtered before a human reads their resume. See if yours makes the cut.

How to Apply on Lever

  • Lever uses a streamlined one-page form — apply in under 5 minutes.
  • LinkedIn import works well; review parsed data before submitting.
  • The cover letter field is optional but visible to reviewers — use it to differentiate.
  • Referral codes from employees can significantly boost visibility of your application.

ANONYMOUS · UNFILTERED

What do employees actually say about Mistral AI?

Real rants from real employees. Read before you apply.

Read Company Rants →