Yash Thapliyal
My work centers around building AI systems that are trustworthy, efficient, and useful.
- EECS @ UC Berkeley
- Currently @ Berkeley AI Research (BAIR)
- Prev @ EleutherAI, Sky Computing Lab, Splunk AI, Google, Amazon, C.Light Technologies, and smartQED
- Interested in Agentic AI, AI Safety & Alignment, Multi-Agent Systems, Reinforcement Learning, AI Memory, and Post Training
Work
Where I've worked and what I've built.
- Designed an evaluation harness for deceptive compliance in tool-using agents, replay-verifying tool calls against fresh environments to detect false completion claims across 481 trajectories, 8 models, and 15 pressure conditions.
- Architected a multi-tier memory system for AI agents spanning short-term, session, and long-term memory, extracting durable facts, user preferences, decisions, and workflow patterns from conversations, documents, and tool traces.
- Distilled a 120B teacher into a 3B on-device student (40x fewer parameters) with MLX/LoRA; explored preference optimization and RL post-training via DPO/GRPO, alongside quantization and data scaling, to identify the best-performing training recipe; built a leakage-resistant evaluation framework with MiniLM embeddings and bipartite matching.
- Built a prompt-optimization platform from 0 to 1 (Docker, FastAPI, SQLAlchemy, dashboard, CLI, MCP) using GEPA via DSPy, lifting task accuracy by up to +50 points (0.27 to 0.77) across 8 optimization jobs.
- Built a FAISS-based reasoning-trace retrieval pipeline over 58K chain-of-thought traces, evaluating whether retrieved solutions from related problems improve LLM mathematical reasoning across 7,680 graded generations on AIME 2025–26.
- Built an end-to-end synthetic speech pipeline generating 1,700+ validated minimal-pair clips with phoneme-level supervision across three voices using eSpeak and Piper TTS.
- Fine-tuned Qwen2.5-Omni-3B with LoRA/PEFT to transcribe speech as spoken rather than “correcting” unusual words, raising accuracy on unseen clips from 72% to 92% and cutting word substitutions by 66%.
- Developed a Gemini/Vertex AI tool router spanning 5 tools for an NL2SQL platform on GKE/AlloyDB; built a 768-dim pgvector index over 1.08 million transactions, with SQL execution, embedding, and vector retrieval each under 550 ms.
- Built a hybrid reasoning layer that converts ambiguous natural-language queries into structured outputs for multi-agent routing and execution.
- Applied language-model disambiguation and multi-turn context propagation to maintain conversational state and resolve follow-up queries.
- Designed and piloted a multi-agent workflow using Strands Agents with AWS Bedrock and MCP for ticket triage, summarization, anomaly detection, and root-cause analysis across 200+ tickets, saving 25+ engineer hours per quarter.
- Implemented a summarization pipeline leveraging the T5 transformer model to generate insights from 1,000+ Stack Overflow posts.
- Designed real-time analytics dashboard with Java/MySQL backend, implementing RegEx filtering to process 500+ DB entries.
- Trained a custom NER model using spaCy for domain-specific classification, improving summarization accuracy by 33%.
Education
Skills
Projects
What I build when nobody tells me what to build.
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Blog
Longer write-ups on projects, experiments, and what I learned from them.
ActionRank
Does Netflix's "score, don't generate" idea work for agent tool selection? Scoring a fixed tool list in one forward pass versus generating the tool name token by token, tested on ToolBench.
Fooling a Trusted Monitor
A fine-tuned Laya monitor for agent traces is near chance on held-out sabotage, and a white-box attack flips its verdicts cheaply wherever the evidence is the agent's own words, sometimes by rewording what the agent claims it did.
Contact
Always happy to talk about hard problems.