Security developer tools
Every listing tagged security, A to Z: 11 tools across 4 categories. Listed in alphabetical order, not ranked.
Argus
Open-source (MIT), self-hosted security operations platform: AI agents triage and investigate alerts with read-only tools, while response playbooks start in shadow mode, use reversible actions and can be approved from Slack.
Charter
Open-source (Apache-2.0) Python library for AI agents that act in your customers' accounts through APIs: each tool is a Pydantic model that mirrors the API field by field with your rules on top, every call is validated before it is sent, the customer a call is for comes from your app rather than the model, and the same declarations produce a reviewable map of everything each tool can reach. Runs in your process with no proxy or telemetry; works with any HTTP API. pip install charter-ai.
Correct Hooks
Open-source (MIT) libraries for TypeScript, Python and Rust that sign and verify webhooks with ed25519 asymmetric signatures and handle key management and rotation; early-stage but usable.
CybeDefend
Security and business rules for AI coding agents: one command installs VibeDefend into Claude Code, Cursor, Copilot or Codex to scan each diff and block risky actions, with SAST, SCA, secrets and IaC scanning; free plan.
Deedglass
Safety layer for AI agents that change databases and health records: rules decide each agent tool call, a check compares what the system really changed with what the agent reported, and each action is sealed as a signed record anyone can verify offline, with a person able to undo it. npx deedglass opens a local app in your browser with no account; works with Claude Code, Cursor, Claude Desktop, VS Code and Postgres. Apache-2.0 core, ee/ under FSL-1.1-ALv2.
Kerno
AI runtime QA for backends: tests user flows against your real stack from inside MCP-capable coding agents.
Lakera Guard (Check Point AI Guardrails)
Runtime guardrails API from Lakera, now part of Check Point and sold as Check Point AI Guardrails: one call to the Guard API screens prompts, documents and model output for prompt injection and jailbreaks, PII and data leakage, harmful content and unknown links, with tool allow and deny lists for agents. Free Community plan for 10,000 requests a month; Enterprise adds self-hosting.
Sourcery
AI code review for GitHub and GitLab, including self-managed GitLab: reviews every pull request with summaries, diagrams and one-click fixes, follows your custom review rules, runs security checks, and can auto-approve low-risk PRs. Free on public repos.
The MCP Census
Checks public evidence for an MCP server and returns PASS, REVIEW, BLOCK or UNKNOWN before you install or call it; lookup, preflight, whole .mcp.json config audits, a change feed, REST API and its own MCP endpoint, no account needed for stats.
Weir
Open-source (Apache-2.0) API key leak detection for AI agents: plants fake keys where real ones live, runs your agent's flows and reports whether they reached traces, logs, console output, the model or other services (leak, clean or incomplete), and in Claude Code shows which of your real keys entered or left a session, with an optional hook that redacts them. pip install weir-scan.
withHuman
Open-source human approval layer that intercepts AI agent tool calls, applies rules, and routes risky actions to reviewers.