Currently, Claude Code has horrible issues with tool calls on Opus 4.8 specifically. As it looks, it misforms tool calls and/or receives misformed tool output, which in turn sometimes makes the model go into straight up infinite loops trying to use the tools but to no avail. I’ve had this happen to me on the current latest Claude Code versions ever since Opus 4.8 came out. As it stands, it’s completely unusable at the moment. The temporary fix I’ve found is to revert to an older Claude Code version. As far as I understand, any version before Opus 4.8 publicly released is fine, so before v2.1.153 ? On those versions, you have to manually input the full model name to use Opus 4.8: /model claude-opus-4-8[1m] in CLI or “model”: “claude-opus-4-8[1m]” in your ~/.claude/settings.json . Personally, I am staying on v2.1.149 , as it’s the version Claude Code automatically updates/downgrades to if you set “autoUpdatesChannel”: “stable” (default “latest” ) on a native installation (through claude update ). I’ve already had very good experience on this version with Opus 4.8 xhigh, definitely no regressions against 4.7, unlike in the new versions. submitted by /u/kurushimee
Originally posted by u/kurushimee on r/ClaudeCode
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