Barclays wants half its developers on Claude Code this year

Every day about 120,000 client emails reach Barclays' Global Markets business, and Claude reads, tags and routes each one before a person opens it. That is one of the live deployments behind the expanded partnership announced by Anthropic, which also sets a target for the bank's engineers: 50% of its developers on Claude Code by the end of 2026.

At a glance

• Barclays is widening its Anthropic partnership across the bank, aiming to speed up software development, modernize legacy systems and make operations more efficient, with a majority of software engineers on Claude Code in 2027.
• The Colleague Knowledge Assistant, live since 2025, uses retrieval-augmented generation, has more than 16,000 colleague users and over one million searches, and supports staff serving over 20 million UK retail customers.
• The announcement gives no developer headcount and no measured results such as time saved or error rates, so the 50% target and the email figures come without a yardstick.

If you have not followed Barclays' AI work, Claude is not its first assistant. According to ComputerWeekly, in June 2025 the bank signed with Microsoft to roll out Microsoft 365 Copilot to 100,000 employees globally, after a trial with 15,000 employees. A July 2025 update on Barclays' Home site described a GenAI colleague assistant "reducing average call handling times" and GitLab Duo rolling out to developers.

Barclays expects half its developers on Claude Code by the end of 2026

The headline target concerns engineers. Barclays expects Claude Code adoption to reach 50% of its developer population by the end of 2026, rising to a majority of software engineers in 2027. The stated goals are faster software development, modernized legacy systems and better operational efficiency across the bank.

Craig Bright, Group Co-Chief Operating Officer, said software engineering and cyber security are both being reshaped by increasingly capable AI systems. In his words, the bank is "moving towards AI as an increasingly agentic capability embedded within how we build, test, secure and operate technology." He said Barclays uses Claude to modernize legacy platforms, improve software quality and free its technical experts for the hardest problems.

Barclays says it applies robust governance, security controls and human oversight to its AI use cases. Paul Smith, Anthropic's Chief Commercial Officer, called the deal a significant milestone for Anthropic in the UK and said Barclays is rolling Claude out with strong security and oversight.

The Colleague Knowledge Assistant has passed one million searches

The deployment with the longest track record sits in Barclays UK. The Colleague Knowledge Assistant, live since 2025, helps staff find information and answers faster when they support the bank's over 20 million UK retail customers. More than 16,000 colleagues have adopted it, and it has handled over one million searches.

Under the hood it is a retrieval-augmented generation setup. Before Claude writes an answer, the system pulls relevant passages from the bank's internal documents and hands them to the model, so the reply rests on Barclays' own material rather than on what the model happens to remember. Think of a new hire who checks the handbook before answering a customer.

Anne Marie Darling, the other Group Co-Chief Operating Officer, said the point is to reduce time spent on routine activities and streamline decision-making, so colleagues can focus their expertise "where it matters most" and solve more complex problems.

Global Markets runs about 120,000 emails a day through Claude

In Barclays' Global Markets business, teams use Claude models to classify, enrich and choose the processing route for incoming client emails. The aim is to prioritize requests and make sure each one contains the information operations colleagues need to act. The platform processes approximately 120,000 emails each day.

The model works like a mailroom clerk: it labels each message by type, fills in the details the next team will look for, and drops it in the right tray. Barclays says this reduces manual handling while helping colleagues spot relevant information faster. According to Barclays' Home site, Markets already had an FX tool called BarxBot in production in July 2025, helping colleagues initiate trades.

How does Claude Code handle a bank's legacy code?

Anthropic's own pitch gives the outline. On the Claude website, Anthropic describes Claude Code for modernization as mapping dependencies and refactoring step by step "while keeping humans in the loop", inside existing CI/CD pipelines and version control. It says the tool preserves business logic, generates unit and regression tests and documents legacy code that never had documentation.

The incremental approach resembles renovating a house one room at a time while the family still lives in it. The Claude site also lists a dedicated Claude Code for Financial Services offering and a Code Modernization Playbook, including material on lowering the cost barrier to COBOL modernization. According to Barclays' Home site, the bank was already "refactoring legacy code, models and complex spreadsheets into their modern form" before this expansion.

The figures Barclays shares measure adoption and volume, not outcomes: there are no handling times, accuracy rates or cost savings for the assistant or the email platform. In our view, the oddest gap is the developer count, because without it the 50% target cannot be turned into a number of people or set against the 16,000 assistant users. Barclays also appears to be running Claude alongside Microsoft 365 Copilot rather than replacing it.

Counting engineers at end-2026

The first checkpoint is the end of 2026, when Barclays expects Claude Code adoption to reach 50% of its developers, with a majority of software engineers to follow in 2027. The announcement does not define adoption, whether by licences issued or by regular use. It also does not say whether the bank will publish the result.