In the fast-evolving world of artificial intelligence, a quiet revolution is underway in software development. Corporate card issuer Brex has leveraged Anthropic’s Claude Code to generate 80% of the code for a new internal system, marking a significant milestone in AI-assisted programming. This development, announced on November 5, 2025, highlights the growing role of ‘agentic’ AI tools that can autonomously handle complex coding tasks.

According to a report by The Information, Brex engineers used Claude Code to create a new codebase for managing financial workflows. The AI tool, which operates as an autonomous coding agent, handled everything from initial architecture to bug fixes, dramatically accelerating development timelines.

The Rise of Agentic Coding Tools

Claude Code, launched by Anthropic in beta as a web-based tool in October 2025, allows developers to delegate tasks via browser interfaces. As detailed in a blog post on Claude’s official site, it runs on Anthropic-managed cloud infrastructure, enabling parallel task execution for bug backlogs and routine fixes.

Brex’s adoption comes amid broader industry trends. Posts on X (formerly Twitter) from users like Matt Turck emphasize Claude Code’s impact, noting that even Anthropic itself uses the tool to create most of its new code. This sentiment echoes in recent news from TechCrunch, which reported on the tool’s expansion to web and mobile platforms.

Brex’s Bold Experiment with AI

Hercules Giaretta Gimenes, a Brex engineer, shared on X his enthusiasm for Claude Code, describing it as a cornerstone of their strategy. The tool’s ability to understand million-line codebases and implement changes has been pivotal. In the Brex case, Claude Code generated code for a system handling expense management and compliance, reducing human effort significantly.

As per InfoQ, Anthropic’s expansion of Claude Code includes enterprise-grade governance and plugin integrations, making it suitable for large-scale applications like Brex’s. This aligns with updates from OpenTools AI, which highlight its advanced architecture for developer-AI collaboration.

Technical Underpinnings and Performance Metrics

Claude Code builds on Anthropic’s Claude 4 model, introduced in May 2025, as noted in Anthropic’s announcement. It features sandboxed execution for Python and Node.js, allowing safe code testing. X posts from Simon Willison describe it as a ‘code interpreter’ upgrade, enabling complex task handling.

Performance data from early tests, shared on Reddit’s r/ClaudeAI and credited to Anthropic’s Python SDK release in June 2025, show Claude Code achieving 70% on SWE Bench metrics. For Brex, this translated to completing tasks in minutes that would take humans hours, as Ashutosh Shrivastava noted on X.

Industry Implications and Competitive Landscape

The Brex example positions Claude Code against rivals like OpenAI’s Codex and Google’s offerings. The Times of India reports that it’s now accessible to Pro and Max subscribers, democratizing AI coding.

Experts on X, including Casper Hansen, praise its no-fluff terminal integration and ease of use over competitors like Aider. Meanwhile, Red Hot Cyber highlights its web accessibility, fostering broader adoption in fintech and beyond.

Challenges and Ethical Considerations

Despite successes, concerns linger about AI-generated code quality and security. Brex mitigated this through human oversight, ensuring only 20% of the codebase required manual intervention. Anthropic emphasizes robust sandboxing in its OpenTools AI coverage.

Industry insiders, as per Mattrics, note potential job displacement, but proponents argue it augments human capabilities. Min Choi’s X post on the initial drop underscores its role in delegating routine tasks, freeing engineers for innovation.

Future Horizons for AI in Development

Looking ahead, integrations like GitHub support, as mentioned in Anthropic’s GitHub repo for Claude Code, promise seamless workflows. Brex’s case, detailed in The Information, could inspire other firms in financial services, where precision is paramount.

Recent X activity from Chris Laub discusses XML prompting techniques enhancing Claude’s performance, potentially amplifying tools like Claude Code. As AI evolves, cases like Brex’s may redefine software engineering paradigms across sectors.