dsv4-subagent-fix

A minimal (~70 lines, zero dependencies) local proxy that fixes DeepSeek V4's subagent incompatibility with Claude Code ≥ 2.1.166.

Quick Start

npx dsv4-subagent-fix

Then add to Claude Code settings.json:

"ANTHROPIC_BASE_URL": "http://localhost:16890"

Restart Claude Code. Subagents work.

Python version:

python3 dsv4_subagent_fix.py &

Problem

Claude Code 2.1.166+ sends thinking: { type: "disabled" } for subagents (no need to show thinking chain to users). When combined with CLAUDE_CODE_EFFORT_LEVEL=max (recommended by DeepSeek), the API request includes output_config or reasoning_effort. DeepSeek's Anthropic-compatible endpoint rejects this combination:

thinking options type cannot be disabled when reasoning_effort is set

This breaks ALL Claude Code subagent/Workflow functionality.

Official DeepSeek issue #1397

Solution

A single-purpose local proxy on localhost:16890 that strips output_config and reasoning_effort from subagent requests only. Main agent requests (thinking.type=enabled/adaptive) pass through completely untouched.

Claude Code (subagent)
  → localhost:16890
    strip output_config / reasoning_effort
  → api.deepseek.com/anthropic (200 OK)

Claude Code (main agent)
  → localhost:16890
    (passthrough, unchanged)
  → api.deepseek.com/anthropic

Quick Start

# Start the proxy
python3 dsv4_subagent_fix.py &

# Configure Claude Code
# In settings.json:
#   "ANTHROPIC_BASE_URL": "http://localhost:16890"

Auto-start with systemd

sudo cp dsv4-subagent-fix.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now dsv4-subagent-fix

Why not dsv4-cc-proxy?

dsv4-cc-proxy is a more comprehensive proxy that fixes 3 API incompatibilities. However, its thinking normalization applies to ALL requests, which can affect main agent reasoning quality. This script takes a more conservative approach — only strip conflicting fields when thinking.type=disabled, leaving main agent requests completely untouched.

| | dsv4-cc-proxy | dsv4-subagent-fix | |---|---|---| | Lines of code | ~430 | ~70 | | Dependencies | httpx, starlette, socksio... | Python stdlib only | | Main agent impact | Side effects | None (passthrough) | | What it fixes | 3 issues | 1 focused fix |

License

MIT