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Tool

appam::tools

Trait Tool 

Source 
pub trait Tool: Send + Sync {
    // Required methods
    fn name(&self) -> &str;
    fn spec(&self) -> Result<ToolSpec>;
    fn execute(&self, args: Value) -> Result<Value>;
}
Expand description

Core trait for tools that can be invoked by agents.

Tools are executable functions exposed to the LLM via JSON schemas. Each tool has a unique name, provides a specification for the LLM, and implements execution logic.

§Examples

use appam::tools::Tool;
use appam::llm::ToolSpec;
use serde_json::{json, Value};
use anyhow::Result;

struct EchoTool;

impl Tool for EchoTool {
    fn name(&self) -> &str {
        "echo"
    }

    fn spec(&self) -> Result<ToolSpec> {
        Ok(serde_json::from_value(json!({
            "type": "function",
            "function": {
                "name": "echo",
                "description": "Echo back the input message",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "message": {
                            "type": "string",
                            "description": "Message to echo"
                        }
                    },
                    "required": ["message"]
                }
            }
        }))?)
    }

    fn execute(&self, args: Value) -> Result<Value> {
        let msg = args["message"].as_str().unwrap_or("");
        Ok(json!({ "output": msg }))
    }
}

Required Methods§

Source

fn name(&self) -> &str

Return the unique, stable function name for this tool.

This name must match the name in the tool specification and is used for routing LLM tool calls to the correct implementation.

Source

fn spec(&self) -> Result<ToolSpec>

Return the tool specification for the LLM.

The specification includes the function signature, parameter schema, and description. This is typically loaded from a JSON file to maintain a single source of truth.

§Errors

Returns an error if the specification cannot be loaded or parsed.

Source

fn execute(&self, args: Value) -> Result<Value>

Execute the tool with the given arguments.

Arguments are provided as a JSON value matching the schema from spec(). The tool should validate inputs, perform its operation, and return a JSON result.

§Errors

Returns an error if arguments are invalid, execution fails, or results cannot be serialized.

§Security

Tool implementations must validate all inputs, avoid shell injection, and respect sandbox boundaries. Never trust arguments from the LLM.

Implementors§