Is Claude Sonnet 5.5 good for coding?

Claude Sonnet 5.5 ranks #2 of 8 on Bug Bench, with 4% fewer counted bugs than average (0.96) from Jun 15 to Oct 4, 2026.

Updated Oct 5, 2026

Claude Sonnet 5.5

As of Oct 5, 2026, Claude Sonnet 5.5 ranks #2 of 8 on Bug Bench with a relative bug rate of 0.96 (4% fewer counted bugs than average), statistically tied with Claude Fable 5.1.

Relative bug rate: 0.96
Rank of 8: #2
Tied with: Claude Fable 5.1

1.00 = average · lower is better

Provider: Anthropic
Released: Sep 28, 2026
Price per 1M tokens: $2 in · $10 out
First seen: Week of Sep 28

Nearby in the ranking

Full ranking →

Claude Sonnet 5.5 and the models ranked closest to it, by relative bug rate.
Rank	Model	Rate
1	GPT-5.6 Sol	0.67
2	Claude Sonnet 5.5	0.96
3= (statistically tied)	Claude Fable 5.1	1.12
4	GPT-6 Astra	1.28

Compared with Claude Sonnet 5

Recent launches →

Claude Sonnet 5.5 had 47% fewer counted bugs per line than Claude Sonnet 5 (0.96 vs 1.80). Claude Sonnet 5.5 vs Claude Sonnet 5

Is Claude Sonnet 5.5 getting worse?

All weekly trends →

Not enough weekly data yet (1 of 6 weeks).

Where it does better or worse

# = rank among models

By coding agent

Claude Sonnet 5.5 relative bug rate by coding agent.
Rank	Agent	Rate
1	Claude Code	0.92

By bug type

Claude Sonnet 5.5 relative bug rate by bug type.
Rank	Bug type	Rate
2	Logic bugs	0.74
2	Testing and docs	1.29

By language

Claude Sonnet 5.5 relative bug rate by language.
Rank	Language	Rate
1	TypeScript	0.54
7	Python	1.70

How widely Claude Sonnet 5.5 is used

Share of AI-written code reviewed by cubic

Latest weekWeek of Sep 28: 2.4%
Peak weekWeek of Sep 28: 2.4%

Compare Claude Sonnet 5.5

Questions and answers

Is Claude Sonnet 5.5 good for coding?: Claude Sonnet 5.5 ranks #2 of 8 on Bug Bench, with 4% fewer counted bugs than average (0.96) from Jun 15 to Oct 4, 2026.
Is Claude Sonnet 5.5 getting worse?: Not enough weekly data yet (1 of 6 weeks).
Which coding agent has the lowest bug rate with Claude Sonnet 5.5?: Claude Code, at 0.92.
How does Claude Sonnet 5.5 compare to Claude Sonnet 5?: Claude Sonnet 5.5 had 47% fewer counted bugs per line than Claude Sonnet 5 (0.96 vs 1.80).

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