Patch release focused on headless streaming: a Messages API–compatible NDJSON output format, optional partial message deltas, plus clearer session rewind and render-mode command behavior.
Changelog
[new] Headless --output-format streaming-messages-json emits newline-delimited JSON in the Anthropic Messages API wire format (system/init, assistant/user frames, terminal result), so existing Messages-style consumers can follow turns, tool use, spend, and stop reasons without a custom parser.
[new]--include-partial-messages streams incremental stream_event framing (text/thinking deltas and related block events) alongside whole messages. It only applies to streaming-messages-json; other formats ignore it with a warning.
[changed]streaming-json is documented and shaped as an ACP-derived NDJSON stream with richer event types (tool_call, tool_call_update, per-response usage, plan, available_commands, plus end/error), with snake_case stop reasons and clearer spend fields.
[changed] Headless json results use snake_case ACP/Messages stop reasons (e.g. end_turn instead of EndTurn), surface cache_creation_input_tokens, and count both cache buckets in total_tokens.
[new]/undo is an alias for /rewind (same Esc Esc gesture) to roll the conversation and files back to an earlier turn.
[changed] The slash-command menu is filtered by render mode: fullscreen-only commands (/find, /jump, /timeline, /theme, /tutorial, /workflows, /dashboard) and minimal-only commands (/expand, /edit-prompt) are hidden in the mode where they cannot run, with a clear message if you type one anyway. --no-alt-screen still counts as fullscreen for this filtering.
[changed] Shell completions (bash, zsh, fish, elvish, PowerShell) cover the new flag and streaming-messages-json output format.
Under the hood
Language server config gains workspaceOpen so servers that need an explicit solution or project list (notably Roslyn/C#) can load real project context instead of treating every file as miscellaneous.
Custom auth_provider_command runs through the platform shell (sh -c on macOS/Linux, cmd /C on Windows), with guidance to use TOML literal strings for Windows paths so backslashes are not eaten as escapes.
Headless and sessions docs were expanded around the new stream formats, token field policy, and the /undo alias.
Runtime settings path now includes a user profile fetch used by the client.
Upgrade notes
If you parse headless --output-format json (or streaming-jsonend / usage lines), expect stopReason values in snake_case (end_turn, max_tokens, …) rather than PascalCase.
Spend automation should treat cache_creation_input_tokens as its own bucket; total_tokens is now input_tokens + cache_read_input_tokens + cache_creation_input_tokens + output_tokens.
Prefer streaming-messages-json when you need Messages API wire compatibility; keep streaming-json for the native ACP-oriented event stream.
