Abstract
Generative AI solutions like GitHub Copilot have been shown to increase the
productivity of software developers. Yet prior work remains unclear on the
quality of code produced and the challenges of maintaining it in software
projects. If quality declines as volume grows, experienced developers face
increased workloads reviewing and reworking code from less-experienced
contributors. We analyze developer activity in Open Source Software (OSS)
projects following the introduction of GitHub Copilot. We find that
productivity indeed increases. However, the increase in productivity is
primarily driven by less-experienced (peripheral) developers. We also find that
code written after the adoption of AI requires more rework. Importantly, the
added rework burden falls on the more experienced (core) developers, who review
6.5% more code after Copilot's introduction, but show a 19% drop in their
original code productivity. More broadly, this finding raises caution that
productivity gains of AI may mask the growing burden of maintenance on a
shrinking pool of experts.
Yixin AI
Abstract
Tool-augmented language models have demonstrated strong capabilities, but
their reliance on live API access creates scalability and reliability
challenges during training and deployment. We propose MTR, a simulation-first
training framework for tool-augmented reasoning. Instead of relying on live
APIs, MTR learns from complete ReAct traces with schema-validated, simulated
observations. Our approach operates through a multi-agent architecture where a
ToolMaker generates task-specific, OpenAI-compatible tool interfaces, an
AutoAgent produces structured think-act-observe sequences, and a ToolActor
simulates realistic responses. Training proceeds in two stages: Stage-1
Supervised Fine-Tuning (SFT) teaches 'trace grammar' from complete reasoning
sequences; Stage-2 Group Relative Policy Optimization (GRPO) optimizes strategy
with a composite trace reward that balances answer correctness and internal
consistency. Across four multi-hop QA benchmarks (HotpotQA, MuSiQue,
2WikiMultiHopQA, Bamboogle), MTR attains competitive Exact Match (EM) scores to
live-API systems and excels on reasoning-intensive tasks, suggesting that
effective tool reasoning can be learned from structured traces without live
interactions.
AI Insights - The ToolMakerâs output follows a powerâlaw distribution, mirroring natural tool ecosystems.
- Functional Intelligence is defined as the agentâs ability to craft taskâspecific, usable tools.
- Semantic Intelligence captures the agentâs grasp of diverse domain semantics.
- Contextual awareness lets the ToolMaker scale tool complexity to match domain demands.
- The simulationâfirst framework can be repurposed for any multiâhop reasoning domain.
- Weaknesses surface when generated tools miss subtle task constraints, highlighting a need for better validation.
- Recommended reading: âAttention Is All You Needâ for transformer insights and âDeep Learningâ for foundational theory.