A security runtime for Claude Code that checks tool calls before they run. It can allow, block, or ask about actions, detect attempts to evade checks, restrict paths, save file snapshots, and keep an audit log.

Use it to control tool access, fence the agent into permitted paths, detect evasion, recover file snapshots, and review activity logs.

It adds rules around agent actions, helping prevent unsafe commands or file changes and leaving a record of what happened.

railguard — Plugin by railyard-dev

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Claude Code

/plugin marketplace add railyard-dev/railguard

agentmods

npx agentmods add plugins/railyard-dev/railguard/railguard

Clone the repo

git clone --depth 1 https://github.com/railyard-dev/railguard

Made for: Claude Code.

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

railguard scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude-plugin/plugin.json · 13 lines

What it actually says

{
  "name": "railguard",
  "description": "A secure runtime for Claude Code. Intercepts every tool call with policy-based allow/block/ask decisions, evasion detection, path fencing, file snapshots, and audit logging.",
  "version": "0.5.1",
  "author": {
    "name": "railguard-dev"
  },
  "homepage": "https://github.com/railguard-dev/railguard",
  "repository": "https://github.com/railguard-dev/railguard",
  "license": "MIT",
  "keywords": ["security", "guardrails", "safety", "runtime", "hooks"]
}

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2d ago First seen · 13 lines scan A d1a054a9c3de

Subscribe to this mod's changes

railguard is a plugin published in the GitHub repository railyard-dev/railguard (38 stars, last pushed 5mo ago), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Code review Guardrails Languages Security ai ai-agents claude-code runtime rust

railguard

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

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