Staff+ Application Security Engineer

About Anthropic Anthropic’s mission is to create reliable, interpretable, and steerable AI systems. We want AI to be safe and beneficial for our users and for society as a whole. Our team is a quickly growing group of committed researchers, engineers, policy experts, and business leaders working together to build beneficial AI systems.

About the role:

Anthropic's Application Security team secures the systems that build, serve, and increasingly are Claude. The attack surface is unlike most AppSec work: multi-agent orchestration, sandboxed code execution, agents holding delegated credentials, untrusted tool output crossing trust boundaries — problems with little prior art and no off-the-shelf playbook.

The way the team works is also different. We use Claude as our primary tool across every part of the job: it drives our static analysis, drafts and fixes vulnerabilities as pull requests, performs first-line bug bounty triage, and assists threat modeling for design reviews. The human work is the judgment layer — system-level reasoning, deciding what matters, and building the next thing the model can't do yet.

This is a builder's role on a senior team. We hire engineers who ship production systems and clear a hands-on threat-modeling bar — people who can find the vulnerability but would rather build the system that finds them all. Every engineer owns a system end-to-end, and the team's work has shaped customer-facing product security — including Claude Code's security review tooling, its security guidance plugin, sandboxing, and auto mode.

Key responsibilities:

• Design, build, and operate Claude-powered security systems — LLM-driven code analysis, automated vulnerability remediation, AI-assisted threat modeling — and own one or more of them end-to-end, including the cross-functional relationships that come with it

• Lead secure design reviews and threat modeling for novel AI systems, identifying risks that don't map to existing frameworks

• Evolve a public bug bounty program where automation handles routine triage and root-cause work, and engineers handle escalations and corner cases

• Partner with Product, Infrastructure, and Research teams as an embedded security owner — consulting on launches, shaping architecture, and influencing decisions where security is the constraint

• Share an operational on-run rotation with the rest of the team — bounty escalations, incident response, and launch consults on systems serving Claude in production

Minimum qualifications:

• Hands-on application and infrastructure security experience, including cloud and containerized environments

• Production-quality coding ability in at least one of Python, Go, Rust, or TypeScript, with a track record of building durable systems rather than one-off scripts

• Practical threat-modeling and vulnerability-identification skills — you've found and reasoned about real bugs in real systems, even if breaking isn't your primary mode

• Demonstrated ability to operate with high autonomy and ambiguity — comfortable being handed a problem and a lot of latitude rather than a spec

• Clear technical communication with both engineers and leadership

Preferred qualifications:

• 7+ years in application security, security engineering, or security-focused software engineering

• Already use LLMs as a core part of how you work, with opinions about where they help and where they don't

• Experience securing agentic, code-execution, or LLM-integrated systems specifically

• Prior ownership of a bug bounty program, vulnerability disclosure program, or vulnerability-management infrastructure at scale

• Background building security automation or developer-facing security tooling

• Offensive security or penetration testing experience

Representative projects

• An increasingly autonomous vulnerability pipeline — LLM-driven code analysis finds the issue, scores it for real exploitability, and opens the fix PR, with humans as the review step rather than the au...