Anthropic released Claude Opus 5.5 on September 22 with lower API prices and a stronger focus on long coding jobs. The company says typical workloads cost about 40% less than on Opus 5, combining cheaper tokens with fewer tokens used to finish a task.
Input tokens cost $4 per million and output tokens $20 per million, both down 20%. Reading cached context costs $0.20 per million tokens, a 60% reduction. Those cache savings can be substantial when a coding agent repeatedly returns to the same project context.
Anthropic reports improvements in codebase migrations, debugging and checking completed work. In its HAProxy translation experiment, Opus 5.5 finished in 9.5 hours against Fable 5.1’s 12 hours at 51% lower cost; both rewrites passed nearly all of the project’s regression tests. The result describes that experiment, rather than a guaranteed saving on another codebase.
Fast mode has separate rates of $8 per million input tokens and $40 per million output tokens. Claude subscribers also receive higher five-hour usage limits and a reset they can save for later. The API savings do not represent a cut to subscription prices.