GLM-5.2 reasoning traces raise developer concerns
Z.ai's new open-weights model, GLM-5.2, is drawing attention due to its exceptionally verbose reasoning process, generating nearly 220,000 characters of thinking traces in a three-turn Rubik's cube test. While demonstrating strong reasoning, this massive output has led developers to question whether the model's prolonged trajectories are practical for efficient agent development.
While deep reasoning is essential for agentic engineering, excessive verbosity in model thinking runs the risk of inflating latency and API costs.
- –**Inefficient Trajectories:** Generating 220K of thinking trace over just three turns for a Rubik's cube indicates a model that is overly verbose, which can slow down agent execution loops.
- –**Context Window Pressures:** Long reasoning traces consume significant tokens, which may restrict the remaining context available for historical inputs and codebase files in multi-turn runs.
- –**Vibe Coding Impact:** Developers using high-effort models need to balance reasoning depth against the practical realities of token budgets and API response times.
DISCOVERED
1d ago
2026-06-20
PUBLISHED
1d ago
2026-06-20
RELEVANCE
AUTHOR
mattpocockuk