Semgrep Guardian

Semgrep Guardian integrates natively with AI coding agents like Claude Code and Cursor to catch security issues before they ship. It bundles the Semgrep MCP server, Hooks, and Skills into a single install, and scans every file an agent generates using Semgrep Code, Supply Chain, and Secrets. When findings are detected, the agent is prompted to regenerate code until Semgrep returns clean results or you choose to dismiss them. The plugin uses each IDE’s native hook or MCP system:

Claude Code: hooks and plugins
Codex: MCP
Cursor: hooks and MCP
GitHub Copilot (Visual Studio, JetBrains, Xcode, Eclipse): MCP
Kiro: MCP
VS Code: MCP
Devin (Windsurf): Cascade hooks

This guide covers setup for each of the preceding products listed, but the plugin works with any MCP client.

Prerequisites

A Semgrep account

Connect to your IDE

Claude Code uses Semgrep’s hosted remote server by default, so you do not need to install the Semgrep CLI locally.

The MCP server bundled with this plugin works on all platforms. On Windows, however, it requires Windows Subsystem for Linux (WSL) for the MCP server to work out of the box.

Start a Claude Code instance:

claude

Open the plugin manager:

/plugin

Go to Discover, search for Semgrep, and click Install.

Tell Claude to load the plugin:

/reload-plugins

Start a new session in Claude to begin the Semgrep login flow:

/clear

The plugin registers a post-tool hook so Claude Code scans every file it writes. Learn more about Claude Code plugins and hooks.

Run Semgrep Guardian locally

The remote server is the recommended default. If you need to run Semgrep locally instead, you can install the local plugin from the semgrep/guardian-local repo.

Install the Semgrep CLI.

Start a Claude Code instance:

claude

Open the plugin manager:

/plugin

Go to Discover. Search for Semgrep, and then click Install.

Load the plugin:

/reload-plugins

Install the Semgrep CLI.

Update your ~/.codex/config.toml file and paste the following:

[mcp_servers.semgrep]
command = "semgrep"
args = ["mcp"]

Codex does not expose a post-write hook, so Semgrep tools are surfaced through MCP and invoked when the agent calls them. Learn more about Codex MCP configuration.

Install the Semgrep CLI.

Find Semgrep in the Cursor Plugin Marketplace, or open Cursor > ⌘⇧J > Plugins. Search “Semgrep” and click Add to Cursor.

Restart Cursor to apply configuration.

In Cursor’s chat, run the /setup-semgrep-plugin skill to finish wiring up the plugin.The plugin uses Cursor hooks (afterFileEdit and stop) to scan code as the agent writes it, and exposes Semgrep tools through Cursor MCP.

Use this tab for GitHub Copilot in Visual Studio, JetBrains IDEs, Xcode, or Eclipse. (For Copilot in VS Code, use the VS Code tab.)

Install the Semgrep CLI.

  {
    "servers": {
      "semgrep": {
          "command": "semgrep",
          "args": ["mcp"]
      }
    }
  }

Follow your IDE’s instructions for where to put this entry: Extending Copilot Chat with MCP servers covers Visual Studio, JetBrains, Xcode, and Eclipse.

Restart your IDE and open Copilot Chat. Semgrep tools become available in Agent mode.

Copilot does not expose a post-write hook, so Semgrep tools are invoked when the agent calls them through MCP.

Install the Semgrep CLI.

Add the Semgrep MCP server to VS Code. Create .vscode/mcp.json in your workspace (or run the MCP: Open User Configuration command from the Command Palette for a user-wide entry) and paste the following:

  {
    "servers": {
      "semgrep": {
          "command": "semgrep",
          "args": ["mcp"]
      }
    }
  }

Reload VS Code. Semgrep tools become available in the Copilot Chat Agent mode.

VS Code does not expose a post-write hook today, so Semgrep tools are invoked when the agent calls them through MCP. Learn more about adding and managing MCP servers in VS Code.

Install the Semgrep CLI.

Create a hooks.json file at ~/.codeium/windsurf/hooks.json and paste the following configuration:

{
  "hooks": {
    "post_write_code": [
      {
        "command": "semgrep mcp -k post-tool-cli-scan -a windsurf",
        "show_output": true
      }
    ]
  }
}

Restart Windsurf to apply hook configuration.

The post_write_code event fires after Cascade writes or modifies any file. Learn more about Windsurf Cascade hooks.

Kiro uses your locally installed Semgrep CLI to run Semgrep on your machine, so install the Semgrep CLI first. Clicking the box below opens Kiro directly so you can add the server; it will not open a new browser tab.

Alternatively, follow the Kiro MCP docs and add this file to your .kiro/settings/mcp.json:

{
  "mcpServers": {
    "semgrep": {
      "command": "semgrep",
      "args": ["mcp"],
      "env": {
        "SEMGREP_APP_TOKEN": "${SEMGREP_TOKEN}"
      }
    }
  }
}

See Kiro docs for more info.

Install the Semgrep CLI, then add the Semgrep MCP Server to your IDE. Semgrep provides sample configuration information that you can use as a starting point. Refer to your IDE’s documentation for specific details on where to add the MCP server configuration.If your IDE supports a post-write or post-tool hook, point it at semgrep mcp -k post-tool-cli-scan -a <ide-name> to scan generated code automatically. The Windsurf tab above shows this pattern.

What hooks does Semgrep Guardian use?

Guardian uses different hooks depending on the IDE you use it in.

Claude Code

In Claude Code, the Guardian plugin registers three hooks:

Hook	What it does
`PreToolUse`	Prevents malware installation. Looks up each package to confirm it isn’t malicious before the agent downloads it.
`PostToolUse`	Scans the code your agent just wrote for hardcoded secrets and software vulnerabilities.
`SessionStart`	Starts the Semgrep login flow if you aren’t already authenticated.

Other IDEs

Other IDEs connect to Guardian through the Semgrep MCP Server. In these IDEs, Guardian is called on a best-effort basis, since it depends on the agent remembering to call it. Deploy Guardian alongside a skill to ensure that the agent calls Semgrep reliably.

What rules does Semgrep Guardian scan with?

Guardian uses different rules depending on the environment in which you use it:

Claude Code remote server (default): scans with the default Guardian ruleset. This is not currently configurable. If you require custom rules, see Semgrep’s #mcp Slack community for assistance.
Claude Code local and all other IDE integrations: scans with the rules enabled for your Semgrep organization through your Policies.

Install the Semgrep CLI

Every IDE except Claude Code runs Semgrep from a locally installed CLI. Claude Code uses Semgrep’s hosted remote server by default and does not need a local CLI.

Install the Semgrep CLI using pipx, uv, or Homebrew. This requires Python 3.10 or later — the Semgrep CLI needs Python at runtime regardless of how you installed the CLI:

# preferred: install using pipx (https://pipx.pypa.io/stable/how-to/install-pipx/)
pipx install semgrep

# preferred: install using uv (https://docs.astral.sh/uv/)
uv tool install semgrep

# best-effort (macOS): install using Homebrew (maintained on a best-effort basis; often lags behind the latest release)
brew install semgrep

NOTEpipx and uv are the preferred installation methods. The Homebrew formula is maintained on a best-effort basis and often lags behind the latest release.Homebrew users: ensure that you’ve added Homebrew to your PATH.

Verify that you’ve installed the latest version of Semgrep:

semgrep --version

semgrep login && semgrep install-semgrep-pro

semgrep login launches a browser window. You can also use the activation link printed in the terminal.

Additional resources

Semgrep’s #mcp Slack community
The Semgrep MCP server repo on GitHub

Get started

Set up and deploy scans

Scan and triage

Semgrep Multimodal

Semgrep Community Edition

References

Semgrep Guardian

Prerequisites

Connect to your IDE

What hooks does Semgrep Guardian use?

Claude Code

Other IDEs

What rules does Semgrep Guardian scan with?

Install the Semgrep CLI

Additional resources

​Prerequisites

​Connect to your IDE

​What hooks does Semgrep Guardian use?

​Claude Code

​Other IDEs

​What rules does Semgrep Guardian scan with?

​Install the Semgrep CLI

​Additional resources

Prerequisites

Connect to your IDE

What hooks does Semgrep Guardian use?

Claude Code

Other IDEs

What rules does Semgrep Guardian scan with?

Install the Semgrep CLI

Additional resources