Symbol pi_θ

The passage around this formula

Let the environment have a latent state $s_t$ , expose an observation $o_t$ , and accept an action $a_t$ . The model and its surrounding prompt produce a policy $a_t \sim \pi_\theta(a \mid o_{\le t}, h_t, g)$. where $h_t$ is retained working state and g is the task objective. A tool translates the proposed action into an environmental transition; the environment returns evidence; and an evaluator determines whether the evidence supports continuing, replanning, escalating, or stopping. The policy may be a frontier model, but the agent is the entire closed loop.

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