# Pre-trade evidence check

Use this when your agent has a trading tool and you want an evidence check before it acts. The agent asks PolyBridge how likely the events behind your idea are, then previews the trade, holds, or declines, based on the pass marks you set. You approve every order.

Tools: `polybridge_forecast` plus your broker tool.

For agents:

- Tool: `polybridge_forecast`. No API key required at the anonymous tier.
- Read-only: PolyBridge never places orders.
- Each forecast call takes 30 to 50 seconds. A timed-out first call is safe to retry once.

## Prompt

```text
You are running a pre-trade evidence check. You have PolyBridge
Forecast (read-only probabilities) and [YOUR BROKER TOOL].

Thesis: [YOUR THESIS, e.g. "semiconductor demand stays strong
through Q1 2027"].
Trade if supported: [YOUR TRADE, e.g. buy $500 of SMH].

Ask PolyBridge [2-4 QUESTIONS]. For each, set a pass mark and a
side: the answer supports the thesis when the probability comes
back under the mark (or over it, if the question asks about
good news).

1. [QUESTION]? Pass mark: [under/over N%].
2. [QUESTION]? Pass mark: [under/over N%].
3. [QUESTION]? Pass mark: [under/over N%].

Report each probability, its range, and the source markets.

If every answer supports the thesis on solid market evidence:
preview the trade with the reason, show it to me, and place it
only after I say yes. If any answer clearly contradicts: write
a short memo saying which, and do not touch the broker.
Anything mixed: hold and say why. If no broker tool is connected, stop after the memo.

Question rules: name dates and years, name the numbers, ask
about scheduled events or prices on specific dates.

End your reply with one line: VERDICT: PREVIEW or VERDICT: HOLD or VERDICT: NO TRADE.

Do not provide financial advice.
```

Fill the brackets with your own idea. Keep the question rules.

Filled in, a question might read: 'Will US retail sales for August 2026 fall month over month? Pass mark: under 30%.'

Want a complete worked example with recorded outputs, a demo broker, and a terminal pipeline? See the [Market Foresight cookbook](/api/cookbooks/agentic-finance).

## Safety

PolyBridge is read-only: it supplies probabilities and never places orders. Your broker tool executes only what you approve. Not financial advice.