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ML / AI Engineer

This role helps build Lucy, the proactive AI coach from Lucy Labs that lives on your desktop as a cloud-backed app, while the product is in development with design partners.

The broad AI role for the founding phase, before it splits.

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Planned work

About the role

At Lucy Labs, this role owns the purpose described below.

The ML/AI Engineer at Lucy Labs builds the intelligent systems that power our coaching platform—competency scoring, recommendation engines, behavioral pattern detection, and LLM orchestration. This role owns core intellectual property that differentiates Lucy Labs from competitors. You'll develop algorithms that measure human Ai competency, detect learning opportunities, and deliver personalized coaching at scale.

This is a high-impact, research-oriented engineering role where your work directly determines product intelligence and value delivery.

The mission

At Lucy Labs, this role's mission is defined by the outcome and work below.

Build intelligent systems that:

Accurately measure and track Ai competency development
Generate personalized learning plans and coaching recommendations
Detect behavioral patterns that signal struggle or success
Orchestrate LLM interactions for coaching quality
Scale to millions of users with consistent intelligence

What you'd own

At Lucy Labs, this role turns its mission into concrete responsibilities in each area.

1. Competency Scoring & Assessment

For 1. Competency Scoring & Assessment, Lucy Labs expects this role to own the responsibilities below.

Design and implement competency calculation algorithms
Build baseline assessment systems
Develop continuous competency tracking mechanisms
Validate scoring accuracy against research framework
Create transparent, explainable competency metrics

2. Recommendation & Coaching Engine

For 2. Recommendation & Coaching Engine, Lucy Labs expects this role to own the responsibilities below.

Build context-aware recommendation systems
Develop real-time nudge trigger algorithms
Create personalized learning path generation
Implement coaching frequency optimization
Design behavioral intervention strategies

3. LLM Orchestration & Integration

For 3. LLM Orchestration & Integration, Lucy Labs expects this role to own the responsibilities below.

Integrate with LLM APIs (OpenAI, Anthropic, etc.)
Build prompt engineering frameworks and libraries
Implement LLM response evaluation and quality control
Develop fallback logic and guardrails
Optimize LLM usage for cost and latency

4. Behavioral Pattern Analysis

For 4. Behavioral Pattern Analysis, Lucy Labs expects this role to own the responsibilities below.

Build iteration pattern detection systems
Develop struggle signal identification algorithms
Create success signal detection mechanisms
Implement prompt quality analysis
Design behavioral analytics pipelines

5. On-Device ML (Phase 3)

For 5. On-Device ML (Phase 3), Lucy Labs expects this role to own the responsibilities below.

Develop local LLM integration for privacy compliance
Implement model optimization (quantization, pruning)
Build on-device inference engines
Create hybrid cloud/local ML architecture
Ensure local processing matches cloud accuracy

6. Research & Experimentation

For 6. Research & Experimentation, Lucy Labs expects this role to own the responsibilities below.

Run A/B tests on algorithms and coaching strategies
Validate new approaches with pilot users
Collaborate with academic research partners
Document findings and algorithm design decisions
Stay current with ML/AI research advances

What success looks like

Lucy Labs defines these milestones as role outcomes, not metrics for measuring the person.

60 days: Competency scoring algorithm implemented and validated
90 days: First users receiving personalized recommendations
6 months: Coaching quality drives measurable competency gains
12 months: ML systems are core competitive advantage

Experience and fit

Lucy Labs looks for the essential experience listed here and treats the rest as helpful, not an automatic barrier.

Must have

3+ years ML/AI engineering experience
Strong Python programming skills
Experience with machine learning frameworks (scikit-learn, PyTorch, TensorFlow)
LLM integration experience (OpenAI, Anthropic, or similar APIs)
Recommendation system development
Data pipeline construction and optimization
Algorithm design and evaluation

Nice to have

On-device ML experience (Core ML, TensorFlow Lite, ONNX)
NLP and prompt engineering expertise
Behavioral analytics or user modeling
Academic research background
Experience with vector databases (pgvector, Pinecone, Weaviate)
A/B testing and experimentation platforms
Startup or 0→1 product experience

How you work

Lucy Labs looks for these working traits alongside technical experience.

Role DNA

Lucy Labs evaluates these traits as part of the fit for this role.

Analytical and research-minded
Comfortable with ambiguity and experimentation
Systems thinker with product intuition
Detail-oriented with scientific rigor
Ownership mentality
Passionate about human learning and capability development

Leadership principles for the role

Lucy Labs expects this role to apply the following leadership principles.

Competency scoring is our core IP—get it right
Algorithms must be explainable and transparent
Quality over sophistication—simple models that work beat complex models that don't
Validate with real users, not just metrics
Research informs, product delivers

Next step

Apply for this role

The Lucy Labs application form opens with this role already selected. You can review the message before sending it.

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Frequently asked questions

Is this role open at Lucy Labs?

Yes. Lucy Labs confirmed this role is open on 25 August 2026.

Where does Lucy Labs base this role?

Lucy Labs bases this role in Madrid, Spain. The exact working arrangement is confirmed during the application conversation.

What does this role own at Lucy Labs?

At Lucy Labs, this role has one central responsibility: The broad AI role for the founding phase, before it splits. The full description sets out the mission, responsibilities, and relevant experience.

How do I apply to Lucy Labs?

At Lucy Labs, use the application form. The role is selected automatically, and you can review it before sending.