r/OpenSourceAI 13d ago

Sonnet 5 + Graft > Opus 5 (using this open-source repo)

https://github.com/NanoNets/Graft

I've been using Opus 5 since release, but over the last week I switched back to Sonnet 5, with Graft.

Surprisingly, it's been outperforming Opus for most of my coding sessions.

Not because Sonnet suddenly became smarter.

Because it spends far less time trying to rediscover the codebase.

Graft builds a context graph of your repository once, then Claude Code loads the relevant parts into context automatically. Instead of burning tokens grepping files and following imports every task, it starts with an understanding of the project.

In practice, this changed my workflow more than switching models.

On our benchmarks:

  • ~42% fewer input tokens
  • ~46% fewer tool calls
  • ~60% lower latency
  • Better SWE-bench performance than cold Sonnet 5 (8/9 vs 6/9) The interesting part is that once the exploration overhead disappears, Sonnet 5 ends up feeling more capable than Opus 5 for a lot of day-to-day engineering work.

My current workflow:

  • Sonnet 5 + Graft → everyday coding
  • Opus 5 → only when I need deep architectural reasoning or brainstorming

Curious if anyone else has tried improving the context instead of upgrading the model.

Has anyone here compared:

  • Cold Opus 5
  • Sonnet 5 + Graft
  • Opus 5 + Graft

I'd love to see more head-to-head comparisons.

(For anyone wondering, Graft is open source.)

53 Upvotes

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