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Housecarl Arbiter
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Quick Start — Connect Arbiter in Two Minutes

Connect Arbiter in Two Minutes

Claude Desktop / Claude.ai

  1. Open Settings → Connectors (or Settings → MCP in Claude Desktop)
  2. Click Add custom connector, name it Housecarl Arbiter
  3. Enter the endpoint URL: https://api.arbiter.housecarl.cloud/mcp/v1
  4. Click Add — the first time you use it, Claude opens a sign-in window; approve it and you're connected via OAuth
  5. After signing in, Arbiter's 46 tools appear in your tool list
  6. Try it: ask Claude to "investigate whether [any claim] using Arbiter"

Google Antigravity (Gemini)

Antigravity connects via API key in the headers field (Antigravity does not yet support MCP OAuth for remote servers).

1. Get an API key — sign up at ui.arbiter.housecarl.cloud, then go to Connection in your console and copy your key.

2. Add to your config — edit ~/.gemini/config/mcp_config.json:

{
  "mcpServers": {
    "arbiter": {
      "serverUrl": "https://api.arbiter.housecarl.cloud/mcp/v1",
      "headers": {
        "x-api-key": "YOUR_API_KEY_HERE"
      }
    }
  }
}

Use serverUrl — not url or httpUrl (Antigravity requires this field for remote Streamable HTTP connections).

3. Verify — in Antigravity CLI, run /mcp or ask "What MCP tools are available?" Arbiter's 46 tools should appear. In Antigravity IDE, open the MCP server manager to confirm the connection.

4. Try it — ask Gemini to "use Arbiter to investigate whether [any claim]"

Other MCP Clients

Any MCP client that supports Streamable HTTP can connect:

  • Endpoint: https://api.arbiter.housecarl.cloud/mcp/v1
  • Transport: Streamable HTTP (MCP 2025-03-26 spec), JSON-RPC 2.0
  • Auth: x-api-key header with your API key

Get an API key at ui.arbiter.housecarl.cloud/connection.

API Key (Direct REST)

For programmatic access without MCP:

curl -X POST https://api.arbiter.housecarl.cloud/api/v1/investigations/analyze \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_API_KEY_HERE" \
  -d '{
    "research_question": "Is the claim true?",
    "actors": [{"id": "src1", "name": "Source", "source_type": "Analyst", "base_reliability": 0.8}],
    "subjects": [{"id": "s1", "name": "Topic", "subject_type": "claim"}],
    "claims": [{"id": "c1", "actor_id": "src1", "subject_id": "s1", "predicate": "accuracy", "value": "true", "content": "The claim text", "valence": "Supports"}]
  }'

What to try first

Ask your AI assistant:

"Use Arbiter to investigate whether Tesla's Q4 revenue claims are supported by the evidence. Use SEC filings and analyst reports as sources."

Arbiter will:

  • Create an investigation session
  • Weigh each source's credibility
  • Detect contradictions between sources
  • Return a scored verdict you can trace and audit

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