A system for text summarization includes an encoder for encoding input tokens of a document and a decoder for emitting summary tokens which summarize the document based on the encoded input tokens. At each iteration the decoder generates attention scores between a current hidden state of the decoder and previous hidden states of the decoder, generates a current decoder context from the attention scores and the previous hidden states of the decoder, and selects a next summary token based on the current decoder context and a current encoder context of the encoder. The attention scores penalize candidate summary tokens having high attention scores in previous iterations. In some embodiments, the attention scores include an attention score for each of the previous hidden states of the decoder. In some embodiments, the selection of the next summary token prevents emission of repeated summary phrases in a summary of the document.