Define state, action and reward
Choose whether actions are tokens, spans or whole responses, and construct a reward model (human labels, classifiers or simulated heuristics) that matches the target behaviour.
Optimise text-generation policy. Track reward and stability.
Reinforcement learning for text generation frames model outputs as actions and uses a reward signal to prefer desirable text. Key engineering concerns include defining the action space (tokens or whole sequences), designing a reliable reward model (human feedback, classifiers or heuristics), and ensuring stable training that avoids reward hacking and catastrophic forgetting.
Learning concept · Not a validated service
Reinforcement learning for text generation frames model outputs as actions and uses a reward signal to prefer desirable text. Key engineering concerns include defining the action space (tokens or whole sequences), designing a reliable reward model (human feedback, classifiers or heuristics), and ensuring stable training that avoids reward hacking and catastrophic forgetting.
A proposed application: fine-tune a conversational agent so it prefers safe, helpful responses according to human-rated rewards. Any real deployment should keep a human reviewer in the loop and not use a prototype for live safety- or policy-critical decisions.
Choose whether actions are tokens, spans or whole responses, and construct a reward model (human labels, classifiers or simulated heuristics) that matches the target behaviour.
Start with a reproducible baseline such as offline fine-tuning with a surrogate reward or a small policy-gradient agent on a simulated environment.
Track average reward, reward variance across seeds, divergence from supervised behaviour, and failure cases where reward is gamed.
Add human-in-the-loop evaluations for safety and quality, and expose corrections that retrain the reward model.
The supplied starter implements a simple epsilon-greedy multi-armed bandit simulation with four Bernoulli arms. It uses NumPy to sample rewards, maintain action counts and running sample-average estimates, and prints action counts, estimated rates and total reward. It does not operate on text, does not include a language model, and does not compute rewards from generated text.
for step in range(1, 2001):
if rng.random() < epsilon:
action = rng.integers(len(true_reward_rates))
else:
action = int(np.argmax(estimated_values))
reward = 1 if rng.random() < true_reward_rates[action] else 0
action_counts[action] += 1
total_reward += reward
estimated_values[action] += (reward - estimated_values[action]) / action_counts[action]The code simulates a 4-armed bandit using Bernoulli rewards and epsilon-greedy action selection; it contains no language model, no token-level or sequence actions, and no reward computation derived from generated text or human feedback.
A proposed extension: fine-tune a pretrained language model with a reward signal (for example, a learned reward model trained on human preferences) using a policy-gradient or PPO agent, starting with small-scale offline data and simulated rewards before human evaluation.
This is a potential application pathway, not a delivered product. The supplied starter does not implement this service or validate it with real users.
Networkers Home runs this topic inside its AI Engineer Course, with placement support and hands-on labs.