Claude Opus 5.5
Claude model for long-running agentic coding and knowledge work
BENCHMARKS
Not in the Epoch Capabilities Index. Epoch benchmarks what it can run, so this is a gap in coverage, not a poor result.
From the lab
Launch announcement · Sep 22, 2026Released Claude Opus 5.5RELEASE DATESep 22, 2026
WEIGHTSClosed weights
CONTEXT WINDOW1M
MAX OUTPUT128K
REASONINGYes
TOOL CALLINGYes
INPUTStext, image, pdf
OUTPUTStext
Specifications from Models.dev. Availability and limits may differ by provider. Benchmark scores come from Epoch AI under CC BY 4.0.