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Public story · 2026-07-14 · high
Claude Code solved 90 of 105 tasks, 85.71%, beating Codex on GPT-5.5 and JetBrains' Junie, which both scored 81.9%.
Why now: JetBrains published the benchmark on its Kotlin blog in July 2026.
JetBrains released an open benchmark of 105 real Kotlin repository tasks, and Claude Code solved 90 of them. Running Opus 4.7 at xhigh effort, it scored 85.71%, beating JetBrains' own Junie agent and Codex on GPT-5.5, both at 81.9%. For teams choosing a coding agent for JVM work, that gap is measured instead of assumed.
Each task requires reading an issue, finding the relevant code, and shipping a patch verified in a container test suite, per JetBrains. Junie ran at max effort, JetBrains' highest setting, and still trailed.
Most agent benchmarks run on Python, so Kotlin developers have had to guess whether the scores translate. This one doesn't blur the variables. It names the agent, the model, and the effort level as separate settings.
JetBrains doesn't say whether Claude Code's 85.71% holds if the task set grows past 105. Junie and Codex could close a four-point gap on the next run. That's the number to watch as more agents get tested against it.
Each link below shares sources, entities, or timing with this story.
JetBrains supports Codex / Shared entities / Shared topic / Earlier coverage / Tension
Linked by a graph relationship (JetBrains supports Codex); both cover Claude Code, Codex, GPT, Opus; overlapping topics (agent, benchmark, claude, code, codex).
JetBrains supports Codex / Shared entities / Shared topic / What happened next
Linked by a graph relationship (JetBrains supports Codex); both cover Codex, GPT, JetBrains, Opus; overlapping topics (agent, codex, jetbrain).
GitHub Copilot supports JetBrains / Shared entities / Shared topic / Earlier coverage / Tension
Linked by a graph relationship (GitHub Copilot supports JetBrains); both cover Claude Code, GPT, JetBrains, Opus; overlapping topics (agent, claude, code).
Codex competes with Claude Code / Shared entities / Shared topic / Earlier coverage
Linked by a graph relationship (Codex competes with Claude Code); both cover Claude Code, Effort, GPT, Opus; overlapping topics (agent, claude, code, effort).
Cursor partners with JetBrains / Shared entities / Shared topic / Earlier coverage
Linked by a graph relationship (Cursor partners with JetBrains); both cover Claude Code, Codex, GPT, Opus; overlapping topics (agent, claude, code).
Claude Code uses Haiku / Shared entities / Shared topic / Earlier coverage / Tension
Linked by a graph relationship (Claude Code uses Haiku); both cover GPT, Opus, Python; overlapping topics (agent, claude, code).
JetBrains supports Codex / Shared entities / Shared topic / Earlier coverage / Tension
Linked by a graph relationship (JetBrains supports Codex); both cover Codex, GPT, JetBrains; overlapping topics (benchmark, code, codex).
Linked by a graph relationship (JetBrains supports Codex); both cover Claude Code, Codex, Opus; overlapping topics (agent, claude, code).