What are the best free alternatives to Security Audit Skill?

Caveman, Codex-X, Qwen Code, Aider, Cline. All are reviewed on Stack Gems in the same category (coding agents); 8 free or open source.

Is there an open-source alternative to Security Audit Skill?

Yes: Caveman (Apache-2.0), Codex-X (OSS/MIT), Qwen Code (Apache-2.0), Aider (Apache-2.0).

Alternatives · Coding Agents

Security Audit Skill alternatives (2026)

Security Audit Skill: MIT agent security-audit skill. Phased findings vs mcp-security-audit; not a SaaS scanner.

Its Catch: Skill only — not a standalone SaaS scanner.

Below: 8 free or free-tier tools from the same category (coding agents), free and open source first, then the closest match by shared tags. Each keeps its own Catch.

1.CavemanViral skill and proxy that forces coding agents to spend fewer tokens
Free / OSS · Apache-2.0 · 114k GitHub stars
VerdictMIT skill surface with BSL engine bits. Use to cut coding-agent token spend; read the BSL boundary before productizing the runtime.
CatchEngine-linked runtime directories (engine/, proxy/, rewriter/, and related) are Business Source License 1.1, not MIT — see LICENSING.md / LICENSE.BSL before embedding or offering a hosted Caveman runtime. Vs LiteLLM: Caveman is output/style compression for agent hosts, not a multi-provider model gateway. Terse output can hide nuance; keep quality checks on hard tasks.
2.Codex-XCodex-specific desktop and CLI workspace for visual configuration and MCP skills
Free / OSS · OSS/MIT · 4.2k GitHub stars
VerdictMIT Codex desktop/CLI companion. Handy for visual MCP and skills configuration; audit auth, relay endpoints, and unrestricted templates before trusting it.
CatchVs T3 Code: Codex-X is Codex-specific visual configuration plus MCP/skills, not a broad remote coding environment or an independent coding model. It handles `auth.json`, supports third-party relays, and allows unrestricted prompt templates — review where credentials go, which endpoint receives requests, and what instructions can execute before using a release. Treat relays as a trust decision, not a convenience toggle.
3.Qwen CodeApache-2.0 multi-surface coding agent (Qwen lineage)
Free / OSS · Apache-2.0 · 28.6k GitHub stars
VerdictApache-2.0 multi-surface coding agent when Qwen-lineage open models + Skills/Teams/MCP beat a closed product CLI.
CatchVs Claude Code: paid product CLI. Vs OpenCode / ZCode / fx: other OSS coding agents — Qwen Code is the Qwen-lineage multi-surface agent with open models+framework, not a tiny Zig binary or Earendil harness fork.
4.AiderAI pair programming in your terminal with any model
Free / OSS · Apache-2.0 · 49.6k GitHub stars
VerdictThe open-source terminal coding assistant for API-key purists.
CatchYou are paying per-token at API rates—can exceed subscription costs on heavy use. No managed infrastructure; you are the ops team. Less polished than commercial alternatives.
5.ClineVS Code extension for human-in-the-loop AI coding
Free / OSS · Apache-2.0 · 70.5k GitHub stars
VerdictMaximum control for developers who approve everything.
CatchHuman-in-the-loop means constant interruptions. Large tasks require many approvals. The pace is slower than autonomous alternatives.
6.OpenAI Codex CLIApache-2.0 OpenAI agent: CLI, IDE, app and cloud
Free / OSS · Freemium · 130k GitHub stars
VerdictOpenAI’s answer to terminal agents — open CLI, paid models; budget the plan or the API.
CatchThe CLI is open source, but the models are not free: you pay through ChatGPT plan quotas or API spend. Codex Web runs on OpenAI’s cloud, not on your machine. The install.sh, brew and npm routes are supply-chain choices, so pin a release binary when that matters. Vs Claude Code or OpenCode: this is OpenAI’s first-party agent, tied to ChatGPT plans or OpenAI API keys.
7.Gemini CLIGoogle open-source terminal agent powered by Gemini
Free / OSS · Apache-2.0 · 107k GitHub stars
VerdictGoogle terminal agent. OSS CLI remains, but consumer quota was cut 2026-06-18; Antigravity (agy) is the consumer path. Gemini-bound by design.
CatchGemini-bound lock-in—not model-agnostic like Goose or Crush. Consumer access (free/Pro/Ultra Google login) ended 2026-06-18; enterprise and API keys still work. Don't build on the old Google-login quota path. The OSS CLI remains. Antigravity CLI is the successor, not a 1:1 swap. Preview/nightly channels move fast; pin stable for production workflows. Enterprise path pushes you toward Vertex AI and Google Cloud project setup.
8.CrushCharm-grade TUI coding agent with LSP and mid-session model switch
Free / OSS · Open-Core · 28.7k GitHub stars
VerdictThe beautiful, model-flexible TUI coding agent. Charm quality.
CatchLicensed FSL-1.1-MIT (competing-use restriction; source-available; MIT after two years—not OSI open-source). Pre-1.0 energy—config is migrating from JSON to crushrc Bash. Not a fully autonomous SWE agent like OpenHands; you stay in the loop. Hyper is Charm own model path if you want a subscription. Metrics on by default (DO_NOT_TRACK / CRUSH_DISABLE_METRICS to opt out).

FAQ

What are the best free alternatives to Security Audit Skill?: Caveman, Codex-X, Qwen Code, Aider, Cline. All are reviewed on Stack Gems in the same category (coding agents); 8 free or open source.
What is the catch with Security Audit Skill?: Skill only — not a standalone SaaS scanner.
Is there an open-source alternative to Security Audit Skill?: Yes: Caveman (Apache-2.0), Codex-X (OSS/MIT), Qwen Code (Apache-2.0), Aider (Apache-2.0).

Security Audit Skill alternatives (2026)

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