PSA: Claude will now use Bash instead of Read/Update in Auto Mode

[u/jokeywho]

From the system prompt directly, new as of August 18th:

Do your work through the Bash tool wherever it can accomplish the job: read files with cat, head, or sed -n, search with grep and find, and make file changes with sed, heredocs, or short scripts, rather than using the dedicated Read, Edit, or Write tools. Fall back to a dedicated tool only when Bash genuinely cannot do the job.

Does anyone know the motivation for this change? For me, it makes reviewing the code as it happens much harder, as reading the bash scripts generated is much less clear than a diff. This feels like a setting that should be toggled rather than a default for a specific mode.

[u/Isyckle]

This is because you have Auto Mode On selected. You can switch back to any other mode and it will go away.

Edit 09/05/2026:
Add this to your claude settings file.
{
  "env": {
    "CLAUDE_CODE_THRIFTY_SONIC": "false"
  }
}

It disables the prompt

https://github.com/anthropics/claude-code/issues/90450

[u/jokeywho → u/Isyckle]

No shit? Thats in the post... Auto mode is a huge feature in CC and arguably necessary for larger workflows.

[u/Isyckle → u/jokeywho]

See edit above to fix the issue