What the Claude Code security plugin does differently
The Claude Code security plugin is an AI-powered security guidance tool that performs real-time code review inside the IDE, detecting and helping fix vulnerabilities as developers write and refine code, so problems are addressed during active sessions instead of surfacing later in pull requests or post-deployment audits. Anthropic’s new Security Guidance Plugin for Claude Code adds AI code vulnerability detection directly into the development workflow, reviewing Claude’s own code changes for common risks and harder-to-spot flaws. Rather than relying only on periodic scans or security teams catching issues at the pull request stage, the plugin checks each change as it happens. It is designed to flag injection flaws, unsafe deserialization routines, insecure DOM APIs, and commonly misused dangerous libraries before code is committed. By embedding this real-time review loop into day‑to‑day coding, it aims to reduce manual security review overhead while keeping the feedback closely tied to the developer’s current context.
Three-stage real-time code review built into the workflow
Anthropic has structured the Claude Code security plugin around three review stages that run automatically during development, without separate tools or extra commands. The first stage runs on file edits, using lightweight pattern checks to catch risky constructs such as eval(), new Function(), os.system(), child_process.exec(), unsafe deserialization calls, and DOM injection patterns involving dangerouslySetInnerHTML or direct innerHTML assignment. A second, deeper stage triggers after each model turn, when Claude analyzes the full git diff for vulnerabilities that pattern matching might miss, including authorization bypass, insecure direct object references, various injection flaws, server-side request forgery, and weak cryptography. The third and most in‑depth stage activates when Claude commits or pushes via its Bash tool, scanning surrounding files, sanitizers, and related code paths to validate findings and cut down on false positives. Together, these layers turn every edit, model response, and commit into a security-aware checkpoint.
Cutting PR security noise and shifting fixes left
By reviewing and fixing vulnerabilities during active coding sessions, the Claude Code security plugin shifts security left in a practical way. Developers can see security warnings while they are still deep in the logic, modify the code, and ask Claude to propose safer implementations before opening a pull request. According to Anthropic, “across our internal rollout and benchmarks, we’ve seen a 30–40% decrease in security-related comments on PRs opened using the plugin. The plugin serves as a lightweight first pass, catching issues before a full code review.” That reduction matters for teams that struggle with noisy or repetitive security feedback during reviews. Instead of treating security as a late-stage gate, the integrated security guidance tool makes every Claude Code session a chance to resolve vulnerabilities early, which can shorten review cycles and reduce back-and-forth between developers and security teams.
Integration, customization, and requirements for teams
The Claude Code security plugin is available for all Claude Code users and installs from the plugin marketplace, integrating directly with existing Claude Code sessions. Once enabled, instant checks run without model calls, so they do not consume additional Claude usage, while deeper reviews share the same usage budget as standard requests. The plugin requires Claude Code version 2.1.144 or later and Python 3.8 or newer; its diff- and commit-level analysis works inside git repositories, but the lightweight file-edit checks can run in any directory. Teams can extend all three review layers with custom rules and repository-specific policies. In addition to configuration options described by Anthropic, organizations can add rules via a claude-security-guidance.md file placed in the repository or distributed through device management. The plugin then enforces these organization-specific requirements alongside its built-in checks, turning Claude Code into a consistent security gate across projects.