---
id: "2026-03-25-claude-code-auto-mode"
url: "https://postcutoff.com/e/2026-03-25-claude-code-auto-mode/"
as_of: "2026-10-10T23:43:00+02:00"
date: "2026-03-25"
date_precision: day
category: product
importance: 3
confidence: high
status: [Confirmed]
sources: 1
editor: Adam Bicz
human_review: null
version: null
---

As of: 2026-10-10 23:43 CEST.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code). Human editor: Adam Bicz.
Canonical page: https://postcutoff.com/e/2026-03-25-claude-code-auto-mode/

# Claude Code auto mode: model-based classifiers approve tool calls instead of the user

Anthropic described Claude Code's auto mode (Mar 25, 2026), which hands permission decisions to a two-stage transcript classifier as a middle ground between approving every action and --dangerously-skip-permissions. It reported a 0.4% false-positive rate and a 17% false-negative rate on real "overeager" actions.

## Key facts
- Motivation: users approved 93% of permission prompts (approval fatigue)
- Two-stage transcript classifier; 0.4% false-positive rate after both stages
- False negatives: 17% on real overeager actions, 5.7% on a synthetic data-exfiltration set
- Evaluated on ~10,000 tool calls from real internal traffic
- Escalates to the user after 3 consecutive or 20 total denials

## What happened

In the post (John Hughes), Anthropic calls auto mode "a new mode for Claude Code that delegates approvals to model-based
classifiers—a middle ground between manual review and no guardrails." The published error rates show it misses about one in six
real overeager actions.

## Why it matters

Auto mode made classifier-gated autonomy the default way many developers ran coding agents in 2026, and its published
false-negative rate is a baseline for later incidents where agents acted beyond their instructions.

## Your AI and this story

- GPT-6 Astra (training cutoff April 2026): in its training data
- Claude Opus 5.5 (training cutoff June 2026): in its training data
- Gemini 3.8 Flash (training cutoff March 2026): in its training data
- Grok 4.7 (training cutoff May 2026): in its training data

## Sources

1. [Anthropic Engineering: How we built Claude Code auto mode](https://www.anthropic.com/engineering/claude-code-auto-mode) (anthropic.com, official)

## Changes

- 2026-10-10 (filed): Created

## Related

- 2026-05-25: [Anthropic engineering](https://postcutoff.com/e/2026-05-25-anthropic-how-we-contain-claude/index.md)