Osv vs Assay

In-depth architectural comparison of the Osv and Assay MCP servers. Compare execution transports, security boundaries, tool capabilities, quality scores, and ready-to-paste client installation snippets for Claude, Cursor, Windsurf, and VS Code.

Which MCP Server Should You Choose?

O

Choose Osv when:

• You need dedicated capabilities in the Security domain.
• You prefer local stdio subprocess transport architecture.
• Your security boundary fits: No auth required (Free / Open Source).
• Primary tools included: query_package_vulns, get_vulnerability, query_by_commit.

Explore Osv Details

Choose Assay when:

• You need dedicated capabilities in the Security domain.
• You prefer local stdio subprocess transport architecture.
• Your security boundary fits: No auth required (Free / Open Source).
• Primary tools included: Deterministic, fail-closed policy enforcement for MCP tool calls, Offline-verifiable, tamper-evident evidence bundles of decisions and observations, Kernel-level IPv4/TCP egress enforcement via eBPF/LSM and Landlock on Linux.

Explore Assay Details

Feature & Specification Comparison

Specification	O Osv Security	Assay Rul1an Security
Summary	OSV.dev (Open Source Vulnerabilities) MCP.	Policy-as-code gate for MCP. A fail-closed proxy that denies risky tool calls before they run, produces offline-verifiable evidence bundles of what executed, and enforces IPv4/TCP egress in-kernel via eBPF/LSM and Landlock on Linux. Deterministic and offline-first.
Category & Scope	Security	Security

Tools & Capabilities Breakdown

Ready-to-Paste Client Configurations

Paste either (or both) of these JSON server blocks into your client config file (e.g. claude_desktop_config.json or ~/.cursor/mcp.json).

{
  "mcpServers": {
    "osv": {
      "command": "npx",
      "args": [
        "-y",
        "osv"
      ]
    }
  }
}

{
  "mcpServers": {
    "rul1an-assay": {
      "command": "npx",
      "args": [
        "-y",
        "rul1an-assay"
      ]
    }
  }
}

Related MCP Server Comparisons