claude --append-system-prompt
Append text to the default system prompt.
Example
claude --append-system-prompt "Always use TypeScript"Source: Claude Code CLI reference, checked 2026-10-24.
More flags
- --system-prompt: Replace the entire system prompt.
- --mcp-config: Load MCP servers from JSON files or strings.
- --strict-mcp-config: Only use MCP servers from --mcp-config.