Build Agents That Write and Execute Code with dspy.CodeAct

Guide the user through building DSPy agents that solve problems by generating and running Python code, rather than calling tools through a fixed interface.

Step 1 — Gather context

Ask the user before writing code:

1. What task should the agent perform? (e.g., data analysis, math computation, file processing, custom calculation) — this guides tool design and max_iters choice.
2. Do you have existing Python functions to expose as tools, or do they need to be defined? CodeAct requires plain functions with type hints and docstrings — not classes or lambdas.
3. What LM provider are you using? Any DSPy-supported provider works — OpenAI, Anthropic, local models, etc.
4. Will you optimize the agent on training examples, or use it for one-off tasks? Optimization with BootstrapFewShot significantly improves performance on repeated tasks.

What is CodeAct

dspy.CodeAct is a DSPy module that creates agents which write Python code to accomplish tasks. Instead of selecting from a predefined set of tool calls (like ReAct), CodeAct generates executable code snippets that use provided tools as Python functions.

The agent works in a loop: