Mizuho builds AI agent platform "Mizuho Cowork" with Claude Agent SDK, starts PoC

Mizuho's move builds on groundwork it had already laid: the company had established a company-wide common AI agent foundation called "Mizuho Wiz Base" and an "agent factory" to support rapid development of agents for individual operations. "Mizuho Cowork" is positioned as a further evolution of those efforts, separating Mizuho-specific business know-how from the underlying agent technology so that the latest AI models and agent technology can be continuously adopted while internal rules and expertise accumulate independently.

The architecture reflects a practical constraint Mizuho highlights in the body: autonomous agents typically run locally on user PCs, which creates challenges for enterprises needing to manage access scope and operation status. By hosting the execution environment and workspace on AWS, Mizuho avoids direct access to employees' business terminals and local data, and because agent operations do not depend on the employee's device, long-running processes can continue while the employee is not operating the terminal. The body also notes that the two-layer harness structure combines Claude Agent SDK's general agent layer with Mizuho's own layer for internal guardrails and Skills.

Looking ahead, the body suggests enterprise use of AI agents is shifting from humans instructing each step toward cloud-based agent work environments where AI autonomously assembles necessary procedures and advances long-running operations even when employees are away from their terminals. Whether Mizuho Cowork can deliver that vision is likely to hinge on the PoC results for tasks requiring specialized judgment and on how well browser operation of legacy systems works in practice, areas the body frames as ongoing verification and development rather than settled outcomes.