Anthropic prices a Claude Code task on Opus 5.5, setting by setting

Osmani's guide prices a task as a loop in which every turn resends the conversation, so turns, cache reads, output and model choice set the bill. At list prices of $4 per million input tokens, $20 per million output tokens and $0.20 per million cache reads, his illustrative 2.8M-token task costs $11.20 in input with no caching and $1.62 at a 90% cache hit rate. The cache lifetime depends on how you pay: an hour on a subscription, five minutes by default on an API key or cloud provider. "On an API key, a six-minute coffee break turns the next $0.02 read into a $0.60 write," he writes. Changing effort or thinking settings, switching models, connecting or disconnecting an MCP server, or compacting can each force a new cache write.

The guide also names the controls. CLAUDE_CODE_SUBAGENT_MODEL puts every subagent on one model, and a model named in a subagent's definition overrides it. Compacting at 150K tokens costs about $0.25 and pays for itself in about ten turns. On one internal 44-ticket customer-support benchmark, moving from Opus 4.8 to Opus 5.5 at low effort cut cost by about 18%, and running /claude-api prompt-audit cut a further 9%. Osmani calls that "an example rather than a number to expect." He also says up front that some of the post's figures are list prices and some are illustrations built from them.

Why it matters: For teams on API keys, the five-minute cache lifetime turns session habits into a cost line: long pauses, mid-task effort changes and MCP churn each pay a full cache write. The guide's own advice is the right test. Run one real task on each model and compare what /usage reports.