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Hermes Agent MCP Setup

This guide shows how to connect Hermes Agent to cvss-calculator-mcp for CVSS 2.0, 3.0, 3.1, and 4.0 Base Score calculations.

Local stdio runs directly on your machine with no rate limits.

Step 1: Install the Binary (Linux / macOS)

Terminal window
curl -fsSL https://get.cvss.my.id/install.sh | bash

Step 2: Add to ~/.hermes/config.yaml

Run hermes mcp add or add cvss_calculator under the mcp_servers: key in ~/.hermes/config.yaml:

mcp_servers:
cvss_calculator:
command: "cvss-calculator-mcp"
args: []

Option 2: Remote MCP (Streamable HTTP)

Connect to https://cvss.my.id/mcp over Streamable HTTP without installing a local binary.

Rate limit: 5 requests per minute per IP. For higher usage, run Local MCP (stdio).

Add the remote server to ~/.hermes/config.yaml:

mcp_servers:
cvss_calculator:
url: "https://cvss.my.id/mcp"

Verify the Connection

Inside a Hermes Agent session (or via CLI), check active MCP servers:

Terminal window
hermes mcp list

Or run /mcp inside the interactive session, then ask Hermes Agent:

Use calculate_cvss to compute the base score for CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Expected Base Score result: 9.3 (CRITICAL).

Troubleshooting

  • Binary not found when starting Hermes Agent: Run which cvss-calculator-mcp and set command: to the absolute path (for example, command: "/usr/local/bin/cvss-calculator-mcp").
  • Rate limit (HTTP 429) on Remote MCP: The public endpoint allows 5 requests per minute per IP. Use Option 1 (Local stdio) for higher throughput.

Official Reference