[BUG] Chat output content broken/missing/incomplete

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Chat output is all out of place, with missing content.

2.0.73 (Claude Code)

<img width="1124" height="1223" alt="Image" src="https://github.com/user-attachments/assets/40ebb8c6-6f5d-4ec2-aec7-bb4bba7df76f" />

What Should Happen?

Expected to see the correct message.

This is the jsonl for the assistant response.

{
  "parentUuid": "1422f284-bdf7-433c-ad37-29dd3ce96937",
  "isSidechain": false,
  "userType": "external",
  "cwd": "C:\\Projects",
  "sessionId": "2780835e-d827-4b5e-ac20-558cd1de891b",
  "version": "2.0.73",
  "gitBranch": "",
  "message": {
    "model": "claude-sonnet-4-5-20250929",
    "id": "msg_01FLBmYUR7PpyA6QVG8He6zE",
    "type": "message",
    "role": "assistant",
    "content": [
      {
        "type": "text",
        "text": "I'm Claude Code, an AI-powered CLI tool designed to help you with software engineering tasks. Here's what I can do:\n\n## Core Capabilities\n\n**Code Development**\n- Write, edit, and refactor code across multiple languages\n- Debug issues and fix bugs\n- Add new features and functionality\n- Review and explain existing code\n- Optimize performance and improve code quality\n\n**Codebase Navigation & Analysis**\n- Search and explore codebases of any size\n- Understand project structure and architecture\n- Trace code flows and dependencies\n- Find specific functions, classes, or patterns\n\n**Development Workflows**\n- Create git commits with properly formatted messages\n- Create pull requests with detailed descriptions\n- Run tests, builds, and other commands\n- Work with various development tools and frameworks\n\n**Project Management**\n- Break down complex tasks into actionable steps\n- Track progress with built-in todo lists\n- Plan implementations before executing\n- Ask clarifying questions when needed\n\n## How I Work\n\n- I can read, write, and edit files directly\n- I use specialized tools for searching, not just basic grep/find\n- I can run terminal commands and interact with your development environment\n- I work with multiple files in parallel when possible for efficiency\n- I follow your codebase's existing patterns and conventions\n\n## Key Features\n\n- **Parallel execution**: I can perform multiple independent tasks simultaneously\n- **Context-aware**: I read and understand your code before making changes\n- **Minimal changes**: I only modify what's necessary to complete your request\n- **Planning mode**: For complex tasks, I can create detailed implementation plans for your approval\n\nWhat would you like help with?"
      }
    ],
    "stop_reason": null,
    "stop_sequence": null,
    "usage": {
      "input_tokens": 2,
      "cache_creation_input_tokens": 10559,
      "cache_read_input_tokens": 13028,
      "cache_creation": {
        "ephemeral_5m_input_tokens": 10559,
        "ephemeral_1h_input_tokens": 0
      },
      "output_tokens": 360,
      "service_tier": "standard"
    }
  },
  "requestId": "req_011CWFAyrdnqJMrN4BqgKDqo",
  "type": "assistant",
  "uuid": "8f4a1a5c-9a5b-46e9-9d1c-d558a2b16d66",
  "timestamp": "2025-12-19T01:24:38.626Z"
}

Error Messages/Logs

Steps to Reproduce

1. load claude
2. Type what can you do?
3. See formatting issues.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.73

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_

"env": {
      "DISABLE_AUTOUPDATER": "1"
}

& ([scriptblock]::Create((irm https://claude.ai/install.ps1))) 2.0.60