MCP server

dagsec is an MCP server at https://app.dagsec.net/mcp (Streamable HTTP, JSON responses). Any MCP client can use it to check packages; install blocking needs a hook, as in the Claude Code plugin, Cursor or Gemini CLI.

Connect

Authenticate with an API key as a bearer token.

Claude Code without the plugin:

claude mcp add --scope user --transport http dagsec https://app.dagsec.net/mcp --header "Authorization: Bearer YOUR_DAGSEC_API_KEY"

Cursor, Windsurf and other clients that take a JSON config:

{
  "mcpServers": {
    "dagsec": {
      "url": "https://app.dagsec.net/mcp",
      "headers": { "Authorization": "Bearer YOUR_DAGSEC_API_KEY" }
    }
  }
}

The server sends instructions telling the agent to call check_package before adding or upgrading a dependency, and how to act on the answer.

Tools

check_package

Checks a package before it is added or upgraded. Read-only.

Argument	Required	Values
name	Yes	Package name, up to 214 characters: axios, requests, serde, github.com/gin-gonic/gin, org.apache.logging.log4j:log4j-core (Maven is groupId:artifactId), Newtonsoft.Json
ecosystem	Yes	npm, pypi, crates, go, maven or nuget
version	No	Exact version to check; omitted means the latest release

The answer is plain text whose first line is the verdict:

First line	Meaning
DO NOT INSTALL: <name> does not exist on <ecosystem>	Not in the registry: misspelled, hallucinated, or a squatting target
DO NOT USE <name>@<version>: N critical/high vulnerabilities. Use <name>@<fix> or later.	Serious vulnerabilities; the fix is named when there is one
RISKY: <name> scores N/100	Health score below 40
OK WITH CAUTION: …	Only moderate or low vulnerabilities
OK: <name>@<version> has no known vulnerabilities; health N/100.	Fine

Below it: the checked and latest versions, up to 15 vulnerabilities with severity, ID and fixed version, and the six health categories with their details.

check_install

Used by the Claude Code plugin's hook. Takes command (a shell command such as npm install [email protected]) and returns a Claude Code hook decision. Agents should call check_package instead.

Limits

Each tool call counts as one agent check. When the month's checks are used up, check_package answers with an error saying so, and check_install lets installs through unchecked. See Plans and limits.