Alternative implementations
Programmatic tool calling is a generalizable pattern that can also be implemented on your own infrastructure. Here's how the approaches compare:
Client-side direct execution
Provide Claude with a code execution tool and describe what functions are available in that environment. When Claude invokes the tool with code, your application executes it locally where those functions are defined.
Advantages:
- Minimal re-architecting of your application
- Full control over the environment and instructions
Disadvantages:
- Executes untrusted code outside of a sandbox
- Tool invocations can be vectors for code injection
Use when: Your application can safely execute arbitrary code, you want the smallest implementation, and Anthropic's managed offering doesn't fit your needs.
Self-managed sandboxed execution
Same approach from Claude's perspective, but code runs in a sandboxed container with security restrictions (for example, no network egress). If your tools require external resources, you'll need a protocol for executing tool calls outside the sandbox.
Advantages:
- Safe programmatic tool calling on your own infrastructure
- Full control over the execution environment
Disadvantages:
- Complex to build and maintain
- Requires managing both infrastructure and inter-process communication
Use when: Security is critical and Anthropic's managed solution doesn't fit your requirements.
Anthropic-managed execution
Anthropic's programmatic tool calling is a managed version of sandboxed execution with an opinionated Python environment tuned for Claude. Anthropic handles container management, code execution, and secure tool invocation communication.
Advantages:
- Safe and secure by default
- Enabled with a tool definition, with no infrastructure to run
- Environment and instructions optimized for Claude
Consider using Anthropic's managed solution if you're using the Claude API, Claude Platform on AWS, or Microsoft Foundry. On Microsoft Foundry, programmatic tool calling requires a Hosted on Anthropic deployment.