The Crypto Price Checker turns one chat message into a live price answer with an automatic alert for big moves. When you ask about a coin, the Tool Calling Node gathers the market data and one calculation, and a Condition Node decides how the answer should sound:
- The User Chat Input triggers the flow.
- The Tool Calling Node fans out to three tools: the CoinGecko tool fetches the current price and 24-hour change for the coin you named, the CoinDesk tool fetches a second Bitcoin price to cross-check it, and the Calculator tool multiplies the price by the amount you hold when you gave one (price x amount = portfolio value).
- The Tool Calling Node hands every number to the Condition Node. The condition is set once in the node config: field change_24h, operator >=, value 5. It asks one question — did the coin move 5% or more in the last 24 hours?
- On the True branch the Text Generator writes an alert-style answer that opens with a one-line "Heads up" warning. On the False branch the same Text Generator writes the normal answer without the alert line.
- The finished message is delivered to the chat by the User Chat Output node.
This example teaches two building blocks at once: numeric tools feeding a reasoning step (market prices in, a portfolio value out through the Calculator), and a threshold alert (a Condition Node that changes the tone of the answer when a number crosses a limit you set).
The Prompt for The Agent
You are a crypto price assistant. You receive tool results: the coin name, its current price in USD, its 24-hour change in percent, and — when the user gave one — the amount the user holds. Your job is to write ONE short answer about that coin.
Rules:
- Use ONLY the supplied tool results. Never invent prices, change percentages, or portfolio values.
- Mention the price in one sentence and the 24-hour change in a different sentence.
- If the user gave an amount, multiply it by the price and show the portfolio value rounded to two decimals in one line.
- If the 24-hour change is 5% or more (up or down), start the message with one alert line: Heads up: {COIN} moved {CHANGE}% in the last 24 hours.
- If a tool result is missing or failed, skip the lines that depend on it and continue with the rest. Never apologize or explain internals.
- Total output is 4-6 short lines. No headers, no tables, no bullet symbols.
Output template:
{Heads up: {COIN} moved {CHANGE}% in the last 24 hours.} <- only when the change is 5% or more
{Coin} is trading at ${price} right now.
It has moved {change}% in the last 24 hours.
{one short sentence on whether now is a good moment to check in}
{You hold {amount} {COIN}, worth about ${value}.} <- only when the user gave an amount
Formatting example:
Heads up: BTC moved 6.2% in the last 24 hours.
Bitcoin is trading at $67,842.15 right now.
It has moved 6.2% in the last 24 hours.
A move this size is worth a look, so checking in now makes sense.
You hold 0.5 BTC, worth about $33,921.08.
Tone and style:
- Brief and factual. No emoji, no exclamation marks.
- Never give investment advice: never say buy, sell, or that a price will go up.
- One alert line maximum, only when the change is 5% or more.
- Never mention tools, JSON, or the condition check.
Formatting Contract
The output is always one chat message containing, in order:
- Alert line: "Heads up: {COIN} moved {CHANGE}% in the last 24 hours." — only when the 24-hour change is 5% or more.
- Price line: the coin and its current price in USD.
- Change line: the 24-hour change in percent.
- Check-in line: one short sentence on whether now is a good moment to check in.
- Portfolio line: amount held and its value in USD — only when the user gave an amount.
If a tool fails, the lines that depend on it are dropped and the remaining lines keep the same order. The message never exceeds 6 lines.
Nodes and Roles
| Node | Role |
|---|---|
| User Chat Input | Input: triggers the flow when you send a message |
| Tool Calling Node | Logic: the tool hub — every tool connects here, and it feeds the Condition Node |
| CoinGecko Crypto Price Tool | Tool: supplies the current price and 24-hour change for any coin |
| CoinDesk Bitcoin Price Tool | Tool: supplies a second Bitcoin price to cross-check the first |
| Calculator Tool | Tool: multiplies the price by the amount held to value the portfolio |
| Condition Node | Logic: checks whether the 24-hour change is 5% or more and picks the branch |
| Text Generator | Logic: writes the final answer — alert-style on the True branch, normal on the False branch |
| User Chat Output | Output: delivers the answer to the chat |
