Cortex Agent Builder
The Agent Builder is where you create a custom Cortex agent. Open it from the Cortex section in the web app (/cortex/builder). The flow is four steps - same labels you see in the app:
- Pick a base
- Teach it
- Set the rails
- Publish
You can click back to any completed step without losing your work.
Custom agents require an active Trade Echo subscription. If you only need chat and presets, see Cortex Quick Start.
Step 1: Pick a base#
Choose one of 18 built-in bases (presets). The base sets which market-data tools the agent prefers - for example flow-heavy vs GEX-heavy.
- Browse the preset cards in Step 1 and pick the closest match to your strategy.
- Not sure? Start with Full Scan for maximum tool access, or match the preset you already use in Cortex chat.
The full preset table lives on Cortex Quick Start → Built-In Presets.
Step 2: Teach it#
This is your strategy layer on top of the base.
Custom instructions#
- Up to 2,000 characters of rules: setups to take, setups to skip, selectivity, exit logic, and tone.
- Copy-paste starters: Ready-Made Custom Prompts.
Rule builder#
Define scan conditions (for example ticker, session window, or signal thresholds) and test the rule against the latest market snapshot before you save. Testing confirms the rule matches real data - not just text on a page.
Chat composer (optional)#
Step 2 also offers a chat composer mode: describe your strategy in plain language and let Cortex propose instruction edits. Switch back to the form view anytime to fine-tune fields by hand.
Step 3: Set the rails#
The trust step. Everything here defines what the agent is allowed to do.
Execution mode#
| Mode | What it does |
|---|---|
| Research only | Reads the market and surfaces signals. No trades - paper or live. |
| Paper trade | Simulates trades in a paper book using your rules. Recommended to start. |
| Live execution | Routes real orders through your linked broker. Requires confirmation before save. |
Live in the Builder (your own agent on your broker):
| Membership | Own-agent live |
|---|---|
| Monthly / yearly | 1 live agent at a time. That one live slot is shared: it can be your own agent or one live Marketplace follow, not both. Your live agent trades on your active Copy Trading account; you cannot pick a different broker per agent. |
| Lifetime | Unlimited live agents, your own and followed. You can pick a broker per agent. |
Paper agents and paper follows never use the live slot. To make a different agent live on a monthly or yearly plan, first move your current live agent back to Paper (Sim) or unfollow the live Marketplace agent. Before 2026-09-26, running your own agent live needed Lifetime; monthly and yearly members can now do it too.
Approval mode#
- Full auto - trades within your rails without asking each time.
- Review mode - every idea queues in Approvals until you approve or it expires.
Start with review mode until you trust the agent's behavior.
Broker binding (live only)#
Live agents need a validated broker connection bound in Trade Echo. If the broker session drops, the agent pauses with Broker offline until you reconnect.
- Monthly / yearly: the broker card is locked to your active Copy Trading account (set it with Set Active on the Copy Trading Broker Accounts tab). If you have no active account, the card points you to Copy Trading first.
- Lifetime: pick any linked account for each agent.
- You cannot switch the broker on an agent while it has open live trades.
Risk rails#
Typical controls on this step:
- Sizing model - how the agent sizes against paper balance or live account context
- Starting balance (paper) - simulation baseline
- Allowed instruments - equity, options, or both
- Allowed expirations - 0DTE, weekly, monthly
- Risk envelope - max positions, max daily orders, max dollars per trade, max contracts per intent, execution timeout
- Drawdown kill-switch - automatic pause on daily loss limits
- Weekly schedule - which days and session windows the agent runs, in your timezone
- Trading calendar - two optional switches that narrow the schedule:
- Trade only during US market hours keeps the agent to NYSE trading days, 9:30 ET to the close (1:00 PM ET on early-close days such as the day after Thanksgiving and Christmas Eve).
- Skip US market holidays keeps the agent idle on NYSE holidays such as Good Friday. Columbus Day and Veterans Day are normal trading days.
Exits#
The Exits card controls how every trade closes. Settings here are enforced by the server after the fill - instructions in Step 2 guide the AI's plan, but they never sell anything on their own.
| Setting | What it does |
|---|---|
| Profit target | The gain (% of the entry premium) the agent aims for on each trade |
| Hard stop | The largest loss (% of the actual entry fill) the position may take before it closes. Leave blank to use the default option minimum |
| Trail after target | Instead of closing at the target, the server trails the position and locks in a floor (Never give back below) so winners can run |
| Take partial profit | Up to 3 steps of "sell X% at +Y%" - each step sells that share of the position the agent opened when the gain is reached. The rest keeps its stop, target and trail |
How partial profits work:
- Each step sells a share of the original position. A step never sells the last contract unless your steps add up to 100%.
- A 1-contract position sells in full at the first step.
- Marketplace subscribers follow the same steps on their own position size. If the agent's position closes, subscribers close too.
- Live agents sell their 1 contract at the first step.
- Writing "take half off at +30%" in your instructions does not trim. Set it here. The Decisions tab flags agents whose instructions mention trimming without steps saved.
- Backtests model your steps, and Why it exited lists each trim on a closed trade.
Authority summary#
Before you save, the authority summary lists exactly what you authorized - mode, caps, schedule, and approval behavior. Read it before continuing to Publish.
Paper history (live)#
Before you switch your own agent to live, the Builder shows how many days and trades it has on paper. Most members run an agent on paper for at least 7 days first. This is a recommendation, not a lock: on any paid plan you can enable live once the broker, rails, and ENABLE LIVE confirmation are complete, and the Builder shows a banner while the agent is short of 7 paper days. Paper mode is always available while you build history.
Step 4: Publish#
Name the agent, choose visibility, and optionally list it on the Marketplace.
Agent name#
A clear name helps you find the agent under My Agents later.
Public description (community listings)#
Up to 500 characters for marketplace listings - what the strategy does, instruments, and session style.
Tags#
Pick tags for strategy, instruments, and vibe so members can filter listings. Tags auto-suggest from earlier steps; you can refine them here.
Visibility#
| Option | Meaning |
|---|---|
| Private | Only you see and run this agent. |
| Community | Published to the Marketplace. Others can subscribe and follow signals. |
Community listings show a data transparency panel before you publish - what performance and config details followers can see.
After you save#
- Private agents appear under My Agents.
- Community agents redirect to the Marketplace My listings tab, where followers can subscribe.
To edit later, open the agent from My Agents or My listings and return to the Builder.
Paper vs live (creators)#
- Every new agent defaults to paper unless you choose otherwise.
- The platform never promotes an agent to live automatically.
- Monthly / yearly: enable live in the Builder when ready. One live agent at a time (shared with a live Marketplace follow), on your active Copy Trading account.
- Lifetime: enable live in the Builder when ready, with no live agent limit and a broker picked per agent.
- Paper fills, slippage, and timing do not match real broker execution. Judge paper results as a simulation, not a guarantee of live P&L.
Cortex agents are research and automation tools, not personalized investment advice.
Next steps#
- Marketplace - browse, list, and subscribe to community agents
- My Agents and Approvals - monitor runs, paper book, and review queue
- Ready-Made Custom Prompts - paste-ready Step 2 instructions