I took 6 tasks that Opus 5.5 had already done in my project and ran them again on Sonnet 5.5 and Haiku 5.5. Same prompts, same files. Then every result was checked against the real answer. Code search (find every file to change for a new feature):
- Files found, out of the 48 the feature really changed: Opus 45, Sonnet 44, Haiku 44
- Cost: Opus $6.17, Sonnet $1.38, Haiku $0.44
- Same quality, so Haiku wins on price Web research (3 tasks, checked against official rulebooks and Google’s help pages):
- Wrong facts: Opus 1, Sonnet 3, Haiku 10
- On Google Play account rules, out of 12 key facts: Opus got 12 right, Sonnet 9, Haiku 5
- Haiku couldn’t open a league’s official rulebook PDF, so it used last season’s rules instead Fact-checking 2 blog posts before publishing:
- Real errors found: Opus 8, Sonnet 7, Haiku 4
- Correct sentences wrongly marked as errors: Opus 0, Sonnet 6, Haiku 30
- If I had followed Haiku, I would have deleted half of a correct post Cost for all 5 web tasks: Opus $3.93, Sonnet $1.59, Haiku $0.12 What I use now:
- Haiku for code search
- Opus for research and fact-checking
- Sonnet when small mistakes are OK Has anyone tested Sonnet vs Opus on research? I’d like to know if my results hold up. submitted by /u/emarkosov
Originally posted by u/emarkosov on r/ClaudeCode
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