The desk

Tools & MCP

MCP servers live in desktop Settings → Tools & MCP.

2 min read

In the app only

Settings → Tools & MCP connects MCP servers into Ask Arcus. Enable is the Debug injection flag. Opening the desk does not auto-start vendor OAuth. Connect explicitly.

Where files live

  • ~/.arcus/mcp.json — user-editable servers (mcpServers + disabled), like other MCP apps’ home JSON
  • ~/.mcp-auth — mcp-remote OAuth tokens after the OS browser login (127.0.0.1 loopback)
  • Application Support/Arcus/arcus-history — call history per account

Datadog

  1. Open Settings → Tools & MCP.
  2. Find Datadog.
  3. Press Connect with Datadog.
  4. Finish the sign-in in the browser.
  5. Ask about logs in Debug or Agent. Ask mode does not query Datadog logs.
  6. Leave API keys in the app. Do not paste them into chat, and do not put them in these docs.

Verify MCP

  1. Settings → Tools & MCP → connect a vendor → switch On.
  2. Finish browser login if prompted. Confirm the row says Connected and a tool count.
  3. Debug or Agent can use that server when the switch is on. Ask does not query vendor logs.

Next

Settings
Desktop Settings: Integrations, Security, Indexing, Tools & MCP.
Ask on the desk
Ask Arcus is a panel in Investigate and Live Call.