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Cohere·Machine Learning Engineer·Technical Phone Screen·Senior

Senior
May 2026

Summary

Cohere ML Engineer interview that was basically one long open-ended design question about making LLMs better at multi-step reasoning. No coding, no leetcode, just a deep technical conversation that covered a lot of ground fast. Felt more like a research discussion than a traditional interview.

Questions Asked (1)

Q1

Given a task that requires multi-step reasoning, such as math word problems, agentic tool use, or code generation with planning, how would you improve an LLM's performance on it? Walk through your full approach across data, training, inference, evaluation, and cost trade-offs.

System DesignTechnical Trade-offsAdaptability & Ambiguity
Author's notes

This question is deceptively wide.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the task and success metrics, then propose a holistic pipeline covering data, training, inference, evaluation, and cost. Emphasize iterative improvements and trade-offs, and highlight how you would measure and optimize each component.

Pro tip: Anchor your answer in a concrete example (e.g., math word problems) to make trade-offs tangible, and always tie improvements back to measurable business impact like accuracy per dollar or latency.

1. Clarify Task and Metrics

Define the task, success criteria (e.g., exact match, pass@k), and constraints (latency, budget). Identify failure modes and baseline performance.

2. Data and Training Improvements

Curate high-quality chain-of-thought data, augment with synthetic examples, and fine-tune with techniques like SFT, RLHF, or DPO. Consider curriculum learning and data filtering.

3. Inference-Time Enhancements

Apply prompting strategies (few-shot, CoT), self-consistency, tree-of-thought, or tool integration. Use verifiers or reward models to select best outputs.

4. Evaluation and Iteration

Build a robust eval set with diverse difficulty, use automated metrics and human review. Analyze errors to guide next iterations.

5. Cost and Trade-off Analysis

Quantify trade-offs between accuracy, latency, and cost. Optimize via model distillation, caching, or adaptive computation. Prioritize high-impact changes.

Key Points to Mention

  • Chain-of-thought prompting and fine-tuning on reasoning traces
  • Self-consistency and majority voting to improve reliability
  • Tool use and external verifiers for math and code
  • Data quality and diversity, including synthetic data generation
  • Evaluation with pass@k and error analysis
  • Cost-aware techniques like distillation, quantization, and caching

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.