Tools

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Overview

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Basic Implementation

import { MagmaAgent } from "@pompeii-labs/magma";

export default class MyAgent extends MagmaAgent {

    // We can define a tool using the @tool decorator
    // We can define parameters for the tool using the @toolparam decorator
    @tool({ description: "Get the current weather for a city" })
    @toolparam({
        key: "city",
        type: "string",
        description: "Name of the city",
    })
    async getWeather(call: MagmaToolCall) {
        const { city } = call.fn_args;
        // Implementation here
        return `The weather in ${city} is sunny!`;
    }

}

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Tool Decorators

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@tool Decorator

@tool({
    name?: string;
    description?: string;
    cache?: boolean;
    enabled?: (agent: MagmaAgent) => boolean
})

• name: The name of the tool.
• description: A description of the tool.
• cache: Try to cache the tool if supported by the provider.
• enabled: Dynamically enable or disable the tool based on agent state. Disabled tools are not supplied to the provider. If omitted, the tool will always be enabled.

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@toolparam Decorator

@toolparam({
    key: string;
    type: string;
    description?: string;
    required?: boolean;
})

• key: The name of the parameter.
• type: The type of the parameter.
• description: A description of the parameter.
• required: Whether the parameter is required to run the tool. Defaults to false.

• enum: Possible values for the parameter.

• properties: An array of MagmaToolParam objects which define the properties of the object.

• items: A MagmaToolParam object which defines the type of the items in the array.

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Advanced Tool Parameters

@tool({ description: "Search database records" })
@toolparam({
    key: "filters",
    type: "object",
    properties: [
        { key: "date", type: "string" },
        { key: "category", type: "string", enum: ["A", "B", "C"] }
    ]
})
@toolparam({
    key: "limit",
    type: "number",
    description: "Maximum number of results",
    required: false
})
async searchDatabase(call: MagmaToolCall) {
    const { filters, limit } = call.fn_args;
    // Implementation here
    return "Search results: ...";
}

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Best Practices

1. Return Values
   • Tools can return a string or object
   • Tools should return meaningful success/error messages
   • Tool return values should be concise and informative
2. Error Handling
   • While you can use a normal return string for failed tools, it is best practice to throw an error. The error message will be passed to the agent and it will attempt to fix the issue.
   Copy

   @tool({ description: "Process a transaction" })
   async processTransaction(call: MagmaToolCall) {
       try {
           // Implementation
           return "Transaction processed successfully";
       } catch (error) {
           throw new Error(`Transaction failed: ${error.message}`);
       }
   }
   

3. Type Safety
   • Use proper TypeScript types
   • Avoid using any type
   • Validate input parameters

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Common Use Cases

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API Integration

@tool({ description: "Fetch user data from API" })
@toolparam({
    key: "userId",
    type: "string",
    description: "User's unique identifier"
})
async fetchUserData(call: MagmaToolCall) {
    const { userId } = call.fn_args;
    const response = await fetch(`https://api.example.com/users/${userId}`);
    const data = await response.json();
    return JSON.stringify(data);
}

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File Operations

@tool({ description: "Read file contents" })
@toolparam({
    key: "path",
    type: "string",
    description: "Path to file"
})
async readFile(call: MagmaToolCall) {
    const { path } = call.fn_args;
    const content = await fs.readFile(path, 'utf-8');
    return content;
}