Paper trade with Gemini CLI

TL;DR

The Gemini CLI example buys 10 SPY shares on a 20-day average crossing above the 50-day average and sells the holding on a crossing below. Simply staying above the average does not trigger another entry. The validated preview has no paper results. Create a separate Paper book, verify its schedule and identity, then review orders and recorded forward history before pausing it.

Create and monitor a separate paper deployment

Deploying an existing live portfolio ID can reactivate real brokerage trading. For this workflow use the newly authored chat candidate and verify the returned deployment is paper. The SDK also separates saved draft IDs from deployment.portfolioId.

Validated example: SPY 20/50 crossover

Starting capital

$10,000

NexusTrade validation recorded October 10, 2026 returned valid:true with no issues. This preview saved nothing and has no forward Paper history.

1. Entry

   Buy 10 shares of SPY whenever SPY's 20-day average price crosses above SPY's 50-day average price and the portfolio holds no SPY.

2. Exit

   Sell 100% of the current SPY position whenever SPY's 20-day average price crosses below SPY's 50-day average price and the portfolio holds SPY.

3. Rule decision example

   If the 20-day average has just crossed above the 50-day average and no SPY is held, the rule proposes buying 10 shares. Simply remaining above does not create another crossing.

4. Exit and equality

   A confirmed crossing below with SPY held proposes selling the full holding. Without the required crossing, that rule does not pass.

Try this example in Gemini CLI

Connect Gemini CLI, then copy the request below. Review the returned result before continuing.

Register remote MCP and authenticate in Gemini CLI

Run the shell commands below. --scope user makes the connection available across your CLI projects; use --scope project instead for this project only. This guide is for Gemini CLI, not the Gemini consumer chat app.

Start gemini in the folder where you will save the research files. Inside that session enter /mcp auth nexustrade, finish NexusTrade browser sign-in, then /mcp list. Use /mcp schema to inspect discovered input schemas. These slash commands belong in Gemini CLI, not your shell.

gemini mcp add --transport http --scope user nexustrade https://nexustrade.io/api/mcp
gemini mcp list
gemini

Confirm access with an owned-resource read

Ask the client to discover tools and call fetch_portfolios, then pass one returned portfolioId as portfolio_id to get_portfolio. Inspect portfolioId, type, name, isActive and strategies; compare them with the same saved book in NexusTrade. Do not copy IDs from a demonstration. An empty list can be valid for a new account.

A tool-not-found error means revisit discovery. An authorization error means check the selected NexusTrade environment/account and OAuth connection. Do not ask the model to invent a replacement identifier.

Use only NexusTrade read tools. Call fetch_portfolios, then pass one returned portfolioId as the portfolio_id input to get_portfolio. Show portfolioId, type, name, isActive and complete strategies. Do not create, edit, backtest, deploy or place orders.

Create a new candidate and observation record

Daily SPY crossover proposal: buy 10 shares only when the 20-day simple moving average crosses above the 50-day average and no SPY position is held; sell the entire SPY position when the 20-day average crosses below the 50-day average. Use the supported CrossAbove/CrossBelow event indicators, compared with 1, rather than treating every above-average day as a new cross.

Create paper/spy-cli-run-ledger.md with the draft ID, exact configuration, intended $10,000 simulated starting capital, activation date and a review date 30 calendar days later. Those are proposed observation inputs, not recorded performance. Historical testing should be reviewed separately before activation.

Ask Gemini CLI to call build_portfolio with the complete candidate. Inspect valid, canonical portfolio and each issue path, component and message. Fix issues and preview again. After valid is true and you have reviewed the rule, pass the same JSON to create_portfolio and read the saved draft with get_portfolio. Verify type=chat and isActive=false. Keep the generated JSON and returned ID in the record; a portfolio name containing paper does not establish deployment type.

Review the paper deployment operation

Show the actual update_portfolio operation before activation: operations contains a deploy entry whose portfolioId is the newly authored chat draft ID. Deploying a chat draft creates a separate paper book. An existing live ID can reactivate brokerage trading, so verify the draft type immediately before the call.

Preview a new candidate with build_portfolio using this rule: Daily SPY crossover proposal: buy 10 shares only when the 20-day simple moving average crosses above the 50-day average and no SPY position is held; sell the entire SPY position when the 20-day average crosses below the 50-day average. Use the supported CrossAbove/CrossBelow event indicators, compared with 1, rather than treating every above-average day as a new cross. Inspect valid, issues and canonical portfolio; fix issues and preview again. When valid and reviewed, pass the same JSON to create_portfolio. Save its full JSON and actual returned ID in paper/spy-cli-run-ledger.md. Use get_portfolio to verify type=chat and isActive=false. Show operations with type deploy and portfolioId equal to that chat ID. Wait for my approval. After activation, find the new deployment with fetch_portfolios and read it with get_portfolio. Stop if type is not paper. Do not deploy an existing live ID.

Verify evaluation and review paper orders

Open the verified running paper portfolio in NexusTrade and inspect its Deployment Center. The Automated Trading switch controls strategy evaluation: if you choose to change it, select Save Changes and read the same portfolio again. Confirm isActive and record the actual deployment frequency. This control is separate from the live-only Autonomous Trading approval policy; paper portfolios remain on manual order review.

When a signal creates a pending simulated order, open Order Management, select Paper and Needs Review, and compare its portfolio, symbol, side and size with the frozen rules before choosing Confirm. Check the resulting order state and paper history. A pending approval is not a filled trade. An empty history can mean no qualifying signal or an unapproved order; it does not justify another deployment.

Verify the running identity and capital

After the approved deployment, use fetch_portfolios to find the new running book and get_portfolio on its returned ID. Confirm type=paper, isActive, strategies, initialValue and the returned deployment settings. Record the actual deployment frequency: Constant and OpenClose are evaluation schedules. A Day backtest interval or a day-based moving-average window does not set the paper evaluation cadence. Compare the capital and rules with the approved record before treating the experiment as started. Keep the chat draft ID and running portfolioId separately.

If several portfolios share a name, use returned IDs and the exact strategies rather than selecting by name alone. A transport timeout does not prove deployment failed. Read the account resources before attempting another deploy; duplicate deployments can create separate experiments.

Observe recorded paper history and recover

Pause the verified paper book

Replace the placeholder with the running paper ID you have just read with get_portfolio. Submit this operation only after reviewing that identity and approving the pause. Read the same ID afterward and require type=paper and isActive=false.

{
  "operations": [
    {
      "type": "undeploy",
      "portfolioId": "<verified-running-paper-id>"
    }
  ]
}

Costs and the next task

The local file and proposed rule are planning artifacts. Research and backtest submissions can consume credits; detailed backtest events increase cost. Check your plan and the proposed operation before submitting. Review the exact connected account before making changes.

For live deployment, review the separate broker guide, exact trading account and permissions. Choose the broker guide that matches your trading account.

Exact validation request and provenance

{
  "name": "Public SEO example - SPY 20/50 crossover",
  "initialValue": 10000,
  "cash": 10000,
  "buyingPower": 10000,
  "strategies": [
    {
      "name": "Buy on a fresh cross",
      "condition": {
        "type": "And",
        "conditions": [
          {
            "type": "Base",
            "lhs": {
              "type": "CrossAbove",
              "indicators": [
                {
                  "type": "SimpleMovingAverage",
                  "targetAsset": {
                    "type": "Stock",
                    "symbol": "SPY",
                    "name": "SPY"
                  },
                  "window": {
                    "length": 20,
                    "interval": "Day"
                  }
                },
                {
                  "type": "SimpleMovingAverage",
                  "targetAsset": {
                    "type": "Stock",
                    "symbol": "SPY",
                    "name": "SPY"
                  },
                  "window": {
                    "length": 50,
                    "interval": "Day"
                  }
                }
              ]
            },
            "comparison": "equal",
            "rhs": {
              "type": "Value",
              "value": 1
            }
          },
          {
            "type": "Base",
            "lhs": {
              "type": "PositionValue",
              "targetAssets": [
                {
                  "type": "Stock",
                  "symbol": "SPY",
                  "name": "SPY"
                }
              ]
            },
            "comparison": "equal",
            "rhs": {
              "type": "Value",
              "value": 0
            }
          }
        ]
      },
      "action": {
        "type": "Buy",
        "targetAsset": {
          "type": "Stock",
          "symbol": "SPY",
          "name": "SPY"
        },
        "amount": {
          "type": "number of assets",
          "amount": 10
        }
      },
      "orderExecution": {
        "type": "Market"
      }
    },
    {
      "name": "Sell on reverse cross",
      "condition": {
        "type": "And",
        "conditions": [
          {
            "type": "Base",
            "lhs": {
              "type": "CrossBelow",
              "indicators": [
                {
                  "type": "SimpleMovingAverage",
                  "targetAsset": {
                    "type": "Stock",
                    "symbol": "SPY",
                    "name": "SPY"
                  },
                  "window": {
                    "length": 20,
                    "interval": "Day"
                  }
                },
                {
                  "type": "SimpleMovingAverage",
                  "targetAsset": {
                    "type": "Stock",
                    "symbol": "SPY",
                    "name": "SPY"
                  },
                  "window": {
                    "length": 50,
                    "interval": "Day"
                  }
                }
              ]
            },
            "comparison": "equal",
            "rhs": {
              "type": "Value",
              "value": 1
            }
          },
          {
            "type": "Base",
            "lhs": {
              "type": "PositionValue",
              "targetAssets": [
                {
                  "type": "Stock",
                  "symbol": "SPY",
                  "name": "SPY"
                }
              ]
            },
            "comparison": "greaterThan",
            "rhs": {
              "type": "Value",
              "value": 0
            }
          }
        ]
      },
      "action": {
        "type": "Sell",
        "targetAsset": {
          "type": "Stock",
          "symbol": "SPY",
          "name": "SPY"
        },
        "amount": {
          "type": "percent of current positions",
          "amount": 100
        }
      },
      "orderExecution": {
        "type": "Market"
      }
    }
  ],
  "supportsFractionalShares": false,
  "supportsCrypto": false,
  "alertsEnabled": false,
  "dividendPolicy": "cash"
}

Compare a historical example

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