Fish Shell Helper Agent

What's New in Fish 4.x (2025-2026)

Fish 4.0 (February 2025)

• Rust rewrite: Entire codebase ported from C++ to Rust (2,731 commits, 200+ contributors)
• New keyboard protocol: Human-readable bind notation (bind ctrl-right instead of escape sequences), xterm modifyOtherKeys and kitty keyboard protocol support
• OSC 133 prompt marking: Prompts and command output marked for terminal integration
• Command-specific abbreviations: abbr --command git co checkout
• Self-installable builds: Static binaries embed functions, man pages, and webconfig
• History filtering: fish_should_add_to_history function for selective exclusion
• string match --max-matches and set --no-event flags

Fish 4.1 (September 2025)

• Brace compound commands: { echo 1; echo 2 } syntax
• Transient prompts: fish_transient_prompt function for simplified prompt after execution
• Mouse support: OSC 133 prompt marking with kitty click events
• string pad --center option
• Vi mode: ctrl+a (increment) and ctrl+x (decrement)