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content[].thinking must be passed back to the API: Claude Code

Quick fix

Temporarily disable automatic updates and downgrade Claude Code to 2.1.150; the original post did not confirm a cc-switch fix.

Symptom

Section titled “Symptom”
Error output
API Error: 400 The `content[].thinking` in the thinking mode must be passed back to the API.

Cause

Section titled “Cause”

Reports say DeepSeek V4 with Claude Code began showing this error in follow-up requests after the first tool call after updating to v2.1.153. Another user said Claude Code v2.1.119 did not trigger it. Some commenters speculated that thinking blocks were not retained during protocol conversion or follow-up requests, while others considered it an unsupported newer Claude Code version in DeepSeek's native Anthropic API rather than a cc-switch proxy issue. The original post did not confirm the root cause or an official fix.

One user reported that downgrading Claude Code worked around the issue; another said it later stopped recurring. Updating to 2.1.154 also produced a different JSON deserialization 400 error, a variant in the same upgrade context, but the post provided no verifiable fix.

Fix

Section titled “Fix”

  1. As a user-reported temporary workaround, disable Claude Code automatic updates and install the specified 2.1.150 version.

  2. After running `npm install -g @anthropic-ai/claude-code@2.1.150`, retest multi-turn tool calls; the original post did not confirm that a cc-switch update resolves this issue.

Affected Versions

Section titled “Affected Versions”
ToolClaude Code
Version2.1.153（报告的受影响版本）
PlatformsWindows

Source Issues

Section titled “Source Issues”

This page is distilled from 1 real issues

FAQ

Section titled “FAQ”
How do I roll back the Claude Code version? Must I uninstall the current version first, and how do I install a specified version or disable automatic updates?
The temporary workaround given in the thread is to disable automatic updates and run `npm install -g @anthropic-ai/claude-code@2.1.150`. The original post does not say whether the current version must be uninstalled first.
Can cc-switch resolve this issue through an update?
The original post did not confirm an official cc-switch fix; discussion disagreed on whether the root cause is in cc-switch.
Section titled “Related problems”
invalid thinkingKimi's deepseek-v4-flash rejects the current thinking parameter; the original post provides no verified solution.1 issues mergedThe `reasoning_content` in the thinking mode must be passed back to the APIConfigure DeepSeek as native mode instead of the default; if it still fails, set `model_reasoning_effort` to `none` in Codex.2 issues mergedSessions may stop responding (JSONL stops being written) — Claude CodeUpdate CC Switch to the latest 4.0 release and retry. If it still hangs, temporarily bypass CC Switch and submit complete reproduction details.1 issues merged

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