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How to Connect Gemini CLI to NinjaTrader 8 with CrossTrade MCP

Gemini CLI is Google's terminal coding agent. It pairs well with CrossTrade MCP for journal-heavy and large-backtest workflows because Gemini's context window is large enough to hold months of trade history in a single prompt. The MCP config requires httpUrl (Streamable HTTP), not url (which is SSE).

OAuth scope: mcp:readSingle-vendor host

Prerequisites

RequirementDetail
CrossTrade subscriptionElite
CrossTrade Add-Onv1.13.0 or higher
NinjaTrader 8Running, broker connected
AccountSim101 for first runs
OAuth scopemcp:read
Install commandnpm install -g @google/gemini-cli
Config file~/.gemini/settings.json
CrossTrade MCP server
https://app.crosstrade.io/v1/api/mcp
Transport: streamable-http. Auth: OAuth 2.1 + PKCE. Request scope mcp:read. Read-only. Inspect accounts, orders, positions, journal, NinjaScript.

Why Gemini CLI for trading​

Gemini's distinctive strength is context length. A typical use case: dump three months of executed trades plus webhook history plus add-on activity into one prompt, ask for patterns. Where Claude or GPT would force you to summarize first, Gemini can hold the raw data.

Step 1: Install Gemini CLI (Node 20+ required)​

# Run once without install
npx @google/gemini-cli

# Install globally
npm install -g @google/gemini-cli

# Or Homebrew
brew install gemini-cli

Sign in:

gemini auth login

Or set GEMINI_API_KEY from aistudio.google.com/apikey.

Free tier

Personal Google accounts get a free tier (~60 req/min, 1,000 req/day, Gemini 3 with 1M context). Workspace accounts and certain regions require a Gemini Code Assist license.

Step 2: Register CrossTrade MCP in ~/.gemini/settings.json​

{
  "mcpServers": {
    "crosstrade": {
      "httpUrl": "https://app.crosstrade.io/v1/api/mcp",
      "headers": {
        "Authorization": "Bearer ${CROSSTRADE_TOKEN}"
      },
      "timeout": 30000,
      "trust": false
    }
  }
}
httpUrl vs url

The httpUrl field selects the modern Streamable HTTP transport. The url field is SSE (legacy). Use httpUrl for CrossTrade — picking the wrong field gives a connection error with no fallback (Google has an open issue tracking this exact gotcha: google-gemini/gemini-cli#15450).

Step 2 (alternative): CLI helper instead of hand-editing JSON​

gemini mcp add crosstrade https://app.crosstrade.io/v1/api/mcp -t http
gemini mcp list

Step 3: OAuth (when the server advertises OAuth metadata)​

CrossTrade supports browser OAuth via the standard MCP dynamic_discovery flow. Add to the server entry:

{
  "mcpServers": {
    "crosstrade": {
      "httpUrl": "https://app.crosstrade.io/v1/api/mcp",
      "authProviderType": "dynamic_discovery",
      "oauth": {
        "scopes": ["mcp:read"]
      }
    }
  }
}

The first tool call opens a browser, completes OAuth, caches the token.

Other authProviderType values:

  • google_credentials — reuse your Google sign-in (for Google Cloud-resident MCP servers)
  • service_account_impersonation — for IAP-protected Cloud Run

Step 4: Long-context journal review​

GetJournalTrades for Sim101 over the last 90 days, all instruments, full detail.
GetWebhookSignals for the same period.
Correlate signals to trades. Tell me: which strategy bucket performed best by
time of day, which signals chronically fail to fill, three changes that would
most reduce drawdown.

This single prompt loads what would take multiple sessions in a smaller-context model.

Step 5: Daily report​

ListAccounts. For each, pull yesterday's closed trades, current watermarks,
and any deployed strategies. One-paragraph status per account.

Inside the REPL​

CommandPurpose
/mcpShow registered servers and connection state
/mcp reloadReconnect to all MCP servers

FAQ​

Do I need Gemini Pro / Code Assist?​

Personal Google accounts get a free tier. Google Workspace accounts and certain regions need a Code Assist license.

Does it support mcp:trade?​

Yes. The same caveats apply: default to mcp:read, escalate only when needed, use Sim101.

Three transports — stdio, SSE, Streamable HTTP — how to pick?​

For CrossTrade (a hosted remote server), use httpUrl (Streamable HTTP). url is SSE (legacy). command is stdio (local subprocess only).

OAuth handshake

The first tool call surfaces an authorization URL. Open it in a browser, approve mcp:read, and return to the harness. The access token is stored by the harness (keychain, config file, or memory depending on the client).

See CrossTrade MCP OAuth for the full flow, and 403/408 troubleshooting if the handshake fails.

Verify the connection

Smoke-test before doing anything stateful:

Call GetMcpCapabilities and McpSelfTest. Then ListAccounts and GetConnections.
Report add-on version, NT8 version, and which accounts are linked.
Read-only scope
You authorized mcp:read. The agent can inspect state but cannot place orders, deploy strategies, or write NinjaScript files.

Troubleshooting

SymptomLikely causeFix
403 insufficient_scopeToken authorized at mcp:read but tool requires mcp:tradeReauthorize the connection and select mcp:trade
OAuth callback failsSystem browser blocked the redirect or popupCopy the auth URL manually, complete it, paste the code back
Tools list is empty after connectServer registered but session did not refreshRestart the harness or trigger a tool list refresh
Add-on offline errorNT8 not running, or add-on not loadedConfirm NT8 is open and the CrossTrade add-on (v1.13.0+) is installed
Server entry uses url and fails to connecturl selects the SSE transport; CrossTrade serves Streamable HTTPUse httpUrl (camelCase) for Streamable HTTP servers
Gemini CLI installs but errors on first runNode version below 20Upgrade Node to 20 or higher; npm install -g succeeds at 18 but the binary fails at runtime
GEMINI_API_KEY not picked upExported in current shell onlyAdd export GEMINI_API_KEY=... to ~/.bashrc / ~/.zshrc / Windows env

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