Evaluating GPT-5.6 Terra on Hack The Box Challenges

OpenAI's GPT-5.6 Terra achieved a 64.6% benchmark score on the HTB-Challenger Benchmark, solving 12 of 16 Hack The Box challenges with a median cost of $0.24 per challenge and a total cost of $10.38. The model solved all 4 Very Easy challenges, 3 of 4 Easy, 3 of 4 Medium, and 2 of 4 Hard challenges, with no false positives and 4 runs where it gave up.

Evaluating GPT‑5.6 Terra on Hack The Box Challenges For some personal observations about this model, please see the Solving Hack The Box Challenges with GPT-5.6 post. This blog post is part of a series of tests for the HTB-Challenger Benchmark The HTB-Challenger Benchmark evaluates LLMs’ ability to find and exploit security vulnerabilities. It tests models against selected Hack The Box challenges of varying difficulty and measures their performance. For more information, visit the HTB-Challenger Benchmark page . . See the benchmark results page for all results and the benchmark methodology to learn how the benchmark is calculated. Cost vs. Benchmark Score The highlighted point is this model. Models closer to the upper-left achieve a higher benchmark score at a lower median cost per challenge. Overall benchmark results Number of challenges: 16 Number of solved challenges: 12 Number of false positives: 0 Runs where the model gave up: 4 Runs that reached the step or cost limit: 0 Runs where the model got stuck: 0 Benchmark score: 64.6% | Metric | Per challenge median | Total | |---|---|---| | Model steps | 16.5 | 428 | | Model cost | $0.24 | $10.38 | | Duration | 00:03:16 | 02:29:17 | | Number of input tokens | 0.23M | 16.61M | | Number of output tokens | 0.01M | 0.26M | Number of read file tool calls | 0.0 | 18 | Number of write file tool calls | 0.0 | 6 | Number of execute command tool calls | 15.5 | 418 | Number of web search tool calls | 0.0 | 6 | Results by challenge difficulty All resource-usage metrics are medians per challenge. | Metric | Very Easy | Easy | Medium | Hard | |---|---|---|---|---| Results | |||| | Number of challenges | 4 | 4 | 4 | 4 | | Number of solved challenges | 4 | 3 | 3 | 2 | | Number of false positives | 0 | 0 | 0 | 0 | | Runs where the model gave up | 0 | 1 | 1 | 2 | | Runs that reached the step or cost limit | 0 | 0 | 0 | 0 | | Runs where the model got stuck | 0 | 0 | 0 | 0 | | Benchmark score | 98.9% | 73.8% | 72.1% | 45.9% | Median per challenge | |||| | Model steps | 6 | 13 | 23.5 | 32 | | Model cost | $0.05 | $0.14 | $0.45 | $0.89 | | Duration | 00:00:39 | 00:02:52 | 00:05:19 | 00:08:06 | | Number of input tokens | 0.03M | 0.12M | 0.70M | 1.59M | | Number of output tokens | 0.00M | 0.01M | 0.02M | 0.02M | Number of read file tool calls | 0.5 | 0.5 | 0.0 | 0.5 | Number of write file tool calls | 0.0 | 0.0 | 0.0 | 0.0 | Number of execute command tool calls | 4.5 | 11.0 | 22.5 | 35.5 | Number of web search tool calls | 0.0 | 0.5 | 0.0 | 0.0 |