PwC says Claude Code cuts legacy-system analysis from six weeks to 2.5 days

PwC is using Claude Code to turn poorly documented legacy software into client-ready analysis, not just to write new code. In a newly published Anthropic case study, partner Ussama Baggili says work that once took six weeks now takes about two and a half days. The account also describes a 30,000-person Claude training rollout underway at PwC.

The analysis became the product

Baggili leads PwC’s legacy and mainframe modernization practice, which helps clients understand and update older business systems. He describes projects arriving at short notice, sometimes with little documentation or code whose original authors have retired. Examples include supply-chain software and healthcare administration systems.

The usual discovery work involved collecting and manually reviewing documentation, interviewing stakeholders, checking findings and revising recommendations. With access to a client’s code, Baggili says, Claude Code can perform most of those activities and help package the results into a deliverable. His six-week-to-two-and-a-half-day comparison concerns that analysis work—not a complete replacement of a legacy system.

The figures are a customer’s account published by the tool’s supplier, not an independently verified benchmark. Baggili says the turning point was realizing that analysis could itself be the finished work. He began producing presentations and HTML deliverables that clients could click through, shifting his use of Claude Code away from an exclusively coding-focused workflow.

The early realization was that the analysis itself was the deliverable.

Ussama Baggili, PwC partner, speaking to Anthropic

A coach inside the coding tool

That experience shaped the training approach. Rather than start business users in Claude’s chat interface and move them to coding tools later, PwC ran a session for 400 leaders and consultants directly in Claude Code. Participants used its command-line interface—a text-based way to operate software—inside the VS Code editor. Baggili wanted them to build technical familiarity, then choose the interface they preferred.

Getting everyone started required preparation. The team reduced installation to a single-line script and built a coaching plugin into the training project. A CLAUDE.md instruction file pointed Claude toward a coaching workflow that appeared when participants first interacted with it. The coach supplied a structure and first prompt, while teaching users to begin with the desired outcome and work backward.

The session simulated three familiar consulting tasks. Baggili describes the progression as follows:

• Proposal responses: participants produced initial drafts for review within 15 to 20 minutes.
• Specifications: another 15 to 20 minutes produced draft functional and technical requirements.
• Applications: by the hour’s end, participants were sharing screenshots of mobile apps they had built.

Baggili did not present those apps as perfect finished products. His account emphasizes participants leaving optimistic and already discussing how to use the tool with their teams. Installation and security hurdles had been addressed before that first experience, which he considered important to preventing early frustration.

From one session to a wider rollout

The 30,000-person training target predates this case study. In its May 14 alliance announcement, PwC said it would train and certify 30,000 U.S. professionals on Claude. It also outlined a Claude Code and Cowork rollout starting with U.S. teams and extending toward its global workforce. Anthropic’s new account describes the training rollout as underway, rather than completed.

Beyond training, Baggili says PwC has packaged proposals and offerings into reusable Claude skills and plugins. He describes an assistant that produces branded presentations, diagrams and workflows in minutes, which the team has also provided to leaders. His next ambition is to repeat the U.S. experience across PwC’s offerings and its roughly 400,000 people—a wider goal, not a deployment milestone the interview says has already been reached.