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iTerm2 Capability Reporting (OSC 1337)
OSC 1337 ; RequestCapabilities queries the terminal to report all its supported capabilities at once. The response is OSC 1337 ; Capabilities=... ST with a structured list of supported features. This provides a single-query alternative to probing individual features, though adoption is currently limited to iTerm2.
How this is tested: Send
OSC 1337 ; ReportCellSize BEL and check for a response indicating iTerm2 protocol support.Analysis2026-03-26
Supported by 1 of 13 backends (8%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✗ no | No OSC 1337 capabilities response |
| Ghostty | 1.3.1 | ✗ no | iTerm2-specific protocol not supported |
| VS Code | 1.112.0 | ✗ no | No OSC 1337 capabilities response |
| Warp | 0.2026.03.18.08.24.03 | ✗ no | No OSC 1337 capabilities response |
| Cursor | 2.6.21 | ✗ no | No OSC 1337 capabilities response |
| tmux | 3.6a | ✗ no | iTerm2-specific protocol not supported by tmux |
| Kitty | 0.46.2 | ✗ no | iTerm2-specific protocol not supported by kitty |
| Terminal.app | 2.15 | ✗ no | No OSC 1337 capabilities response |
| GNU Screen | 5.0.1 | ✗ no | iTerm2-specific protocol not supported by Screen |
Headless Backends
Parser correctness only — a ✓ means the parser accepts the sequence.
| Backend | Version | Support | Notes |
|---|---|---|---|
| vterm | 0.2.0 | ✓ yes | |
| Alacritty | 0.26.0 | ✗ no | iTerm2-specific protocol not supported |
| vt100 | 0.2.1 | ✗ no | iTerm2-specific protocol not implemented — pure TypeScript emulator |
| WezTerm | 0.1.0-fork.5 | ✗ no | iTerm2-specific protocol not supported |