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Last updated 29 August 2026

Install Hexum MCP in Cursor in 3 steps

  1. Turn on usage billing at /app and mint a key.
  2. Paste the JSON below, or use the command on the agent page.
  3. Reload MCP. Confirm tools/list.
mcp.json
{
  "mcpServers": {
    "hexum": {
      "serverUrl": "https://hexum.dev/mcp",
      "headers": { "Authorization": "Bearer hexum_live_…" }
    }
  }
}

AUTH: missing, invalid, or revoked key. BILLING (HTTP 403): key valid, Usage or Teams billing off. Per-agent: one install, every agent.

FAQ

Why did MCP return BILLING or AUTH?

AUTH means the key is missing, invalid, or revoked. BILLING (HTTP 403) means that key’s billing source is off: personal Usage for a personal key, or Teams billing for a team key. Turn the matching plan on at /app, or mint a key against the plan that is on.

How do I add Hexum to Cursor?

Turn on usage billing at /app, mint a hexum_live_ key, paste the mcpServers JSON into Cursor Settings → MCP or ~/.cursor/mcp.json, then reload. Details: /cursor.

Does Hexum replace Cursor or Claude Code?

No. Hexum is a hosted MCP server. You keep Cursor, Claude Code, Antigravity, Codex, or Grok. Hexum is not an IDE and not a model.