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Shows how to give an agent a code execution capability using a custom execute_code tool. The LLM writes a short script, the sandbox runs it, and the output is returned for the LLM to explain. The sandbox is pluggable — swap the runtime without changing the tool. Source: examples/agent_with_code_execution/

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What it demonstrates

  • execute_code custom tool — interfaces.Tool with language and code parameters
  • SandboxRuntime interface — pluggable sandbox (local os/exec, Docker, cloud APIs)
  • LLM writes code, runs it, reads output, replies — never makes up results
  • Sandbox isolation — Docker runner uses --network none and memory limits

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Run

From examples/: Local sandbox — needs Python or Node installed on host: 
go run ./agent_with_code_execution "Write a Python script that prints the first 10 Fibonacci numbers"
Docker sandbox — isolated, no host interpreter needed: 
SANDBOX_ENV=docker go run ./agent_with_code_execution "Write a Python script that prints the first 10 Fibonacci numbers"
Requires LLM_APIKEY in examples/.env.

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Key code

// newSandbox picks the execution environment from SANDBOX_ENV (default: local os/exec).
// Swap newLocalRunner for newDockerRunner, a Lambda runner, Modal, E2B, etc.
sandbox, err := newSandbox()

a, err := agent.NewAgent(
    agent.WithLLMClient(llmClient),
    agent.WithTools(NewCodeTool(sandbox)),
    agent.WithAgentMode(agent.AgentModeAutonomous),
    agent.WithToolExecutionConfig(agent.ExecutionConfig{
        Timeout:     2 * time.Minute,
        MaxAttempts: 1,
    }),
)

result, err := a.Run(context.Background(), prompt, nil)
Execute blocks until SandboxRuntime.Execute returns the program output and exit code.

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Expected output

user: Write a Python script that prints the first 10 Fibonacci numbers

A: Here are the first 10 Fibonacci numbers: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34.

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Learn more

Code Execution in Agents

Sandbox options, isolation, timeout config, cloud runtimes

Execution config

Tool execute timeout and max attempts