claude-fix

Community fix scripts for Claude Code bugs.

npx @akz-tools/claude-fix <fix-name> <session-id>

Available Fixes

orphaned-toolcalls — Fix "400 tool use concurrency" error

API Error: 400 due to tool use concurrency issues. Run /rewind to recover the conversation.

If you're seeing this error in Claude Code and /rewind doesn't help — this tool fixes it.

The most reported unfixed bug in Claude Code (15+ GitHub issues, countless Reddit posts). Makes conversations permanently unresumable. /rewind doesn't help. /compact can make it worse.

Usage

# Step 1: Find your broken session ID
npx @akz-tools/claude-fix orphaned-toolcalls --list

# Step 2: Fix it
npx @akz-tools/claude-fix orphaned-toolcalls <session-id>

# Step 3: Resume
claude --resume <new-session-id>

You can also dry-run to see what's wrong without fixing:

npx @akz-tools/claude-fix orphaned-toolcalls --dry-run <session-id>

How to find your session ID

• In Claude Code, run: /conversations
• Or: ls -lt ~/.claude/projects/*/*.jsonl | head -20
• Or: npx @akz-tools/claude-fix orphaned-toolcalls --list

What it does

Creates a fixed clone of your broken conversation. The original is never touched.

Root cause

Claude Code stores conversations as a tree (each message links to its parent via parentUuid). When it runs tools concurrently (e.g., two Read calls in parallel), it creates branches:

assistant: "Let me read both files"
├── tool_use: Read(file_A)     ← branch 1
│   └── tool_result: <contents of A>
└── tool_use: Read(file_B)     ← branch 2
    └── tool_result: <contents of B>
        └── ... conversation continues on this branch

When Claude Code flattens this tree for the Anthropic API, it follows one branch — losing the tool_result on the sibling branch. The API sees a tool_use without a matching tool_result and returns 400.

User interruptions (pressing Escape) can also create consecutive same-role messages, which violate the API's alternating message requirement.

The fix:

1. Walks the parentUuid chain to find the linearized path
2. Detects missing tool_result blocks and consecutive same-role messages
3. Grafts missing results from sibling branches (they exist in the JSONL, just on the wrong branch)
4. Inserts synthetic error results for truly lost tool calls
5. Merges consecutive user messages from interruptions
6. Rebuilds with a clean linear parentUuid chain

Requirements

• Node.js 18+
• macOS or Linux

Contributing

Found another Claude Code bug that needs a fix script? PRs welcome. Each fix goes in its own directory:

claude-fixes/
├── cli.mjs                    # Router — npx @akz-tools/claude-fix <name>
├── fix-conversation/          # Fix: orphaned-toolcalls
│   └── index.mjs
├── fix-next-bug/              # Fix: next bug someone finds
│   └── index.mjs
└── ...

License

MIT