What probably matters to youSection of the release
What
Results returned in stream-json format (used with claude -p) now have a documented seq field, a delivery sequence number counting how many results the run has numbered before this one, starting at 0. It counts in the order results are written, not the order they were produced, and it still increments even if a particular write fails, so a gap in the sequence means a result was lost. This field is absent from the in-process engine surface and from error results built locally by cloud-relay clients.
Why
This gives consumers of stream-json output a way to detect whether any results were dropped in transit, by watching for gaps in the sequence numbers.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Added sinceA small documentation edit on Claude Code gateway compatibility guide touched a line naming seq after this was published.Deliver each response's full event sequence without dropping, duplicating, or reordering events. When an event references a content block whose `content_block_start` never arrived, or a block whose `content_block_stop` already arrived, Cla…llm-gateway-protocolsee the edit
Added sinceA small documentation edit on Best practices for Claude Code touched a line naming claude -p after this was published.For large migrations or analyses, you can distribute work across many parallel Claude invocations. Run [`/batch <instruction>`](/docs/en/commands#all-commands) to have Claude split the change across 5 to 30 subagents. Each subagent works i…best-practicessee the edit
Confirmed sinceAnthropic's documentation has since written up claude -p, on Claude Code changelog.* Fixed resumed `claude -p` sessions whose tools all come from MCP servers failing with "At least one tool must have defer\_loading=false"changelogsee the edit
Confirmed sinceAnthropic's documentation has since written up seq, on preserved-thinking.Earlier thinking blocks aren't in the prefix, but each thinking block records which thinking block came before it, across turns. You can remove thinking blocks from the start of the history (oldest first), from the end, or all of them. Wha…build-with-claude/preserved-thinkingsee the edit
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up seq, on preserved-thinking.
