Chinese AI company Z.ai has launched GLM-5.1, an open-source coding model it says is built for agentic software engineering. The release comes as AI vendors move beyond autocomplete-style coding tools toward systems that can handle software tasks over longer periods with less human input.

Z.ai said GLM-5.1 can sustain performance over hundreds of iterations, an ability it argues sets it apart from models that lose effectiveness in longer sessions.

As one example, the company said GLM-5.1 improved a vector database optimization task over more than 600 iterations and 6,000 tool calls, reaching 21,500 queries per second, about six times the best result achieved in a single 50-turn session.

In a research note, Z.ai said GLM-5.1 outperformed its predecessor, GLM-5, on several software engineering benchmarks and showed particular strength in repo generation, terminal-based problem solving, and repeated code optimization. The company said the model scored 58.4 on SWE-Bench Pro, compared with 55.1 for GLM-5, and above the scores it listed for OpenAI’s GPT-5.4, Anthropic’s Opus 4.6, and Google’s Gemini 3.1 Pro on that benchmark.