Claude Code by version
Opus 5.5 · Claude Code -p · default tools, no MCP servers or plugins · one run per version
Changes
2.1.310: overhead unchanged, wording unchanged.
- 2.1.31023 Oct 2026no change
- 2.1.30922 Oct 2026+0.7%Tools+106 tokens · +$0.021 / 1k requests · Bash wording +3/−0 sentences
- 2.1.30822 Oct 2026+2.5%Tools+393 tokens · +$0.079 / 1k requests · Agent wording +15/−3 sentences
- 2.1.30621 Oct 2026no change
- 2.1.30419 Oct 2026−0.1%Notices−3 tokens · −$0.001 / 1k requests · wording +1/−1 sentences
Session variance
2.1.2802.1.308
lower is bettertokens / sessionmedianpeakdipwording change
Tokens / request
21,058
no change vs 2.1.309
+7.6% vs 2.1.280
System prompt
1,380
no change vs 2.1.309
+8.4% vs 2.1.280
Tools
16,057
no change vs 2.1.309
+7.4% vs 2.1.280
Notices
3,621
no change vs 2.1.309
+8.5% vs 2.1.280
Tokens / session
7.50M
2.1.308
System prompt 7%Tools 76%Notices 17%
Overhead
vs 2.1.280
2.1.2802.1.310
lower is betterwording change
Breakdown
vs 2.1.280
2.1.2802.1.308
lower is bettermedianpeakdip