You'll notice
When an MCP server rejects a late tool addition, the beta stays rejected until you run /clear or /compact.
When an MCP server rejects a tool addition with header_rejected, block_type_unknown, or model_unsupported, Claude Code now logs a warning, falls back to the ToolSearch announcement path, and sticky-rejects the corresponding beta for the rest of the session until /clear or /compact, rather than retrying it repeatedly.
Names in the bundle/clear/compact
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 since
A small documentation edit on How the agent loop works touched a line naming /clear after this was published.
With [streaming input](/docs/en/agent-sdk/streaming-vs-single-mode), a message that is still queued when a turn ends at the max-turns limit stays queued. Claude Code doesn't add it to that turn's last model call. It starts a new turn for t…agent-sdk/agent-loop see the edit
Added since
A small documentation edit on whats-new-fable-5-1 touched a line naming /compact after this was published.
To keep thinking valid across a long session, treat the conversation as append-only. Add instructions with a [mid-conversation system message](https://platform.claude.com/docs/en/build-with-claude/mid-conversation-system-messages) ([turn-s…models/fable-5-1/whats-new-fable-5-1 see the edit
Confirmed since
Anthropic's documentation has since written up /clear, on Hooks reference.
* **Later in a running session**: after `/clear` or a compaction, `SessionStart` fires again with the servers already available, and its `mcp_tool` hooks run.hooks see the edit
Confirmed since
Anthropic's documentation has since written up /compact, on Claude Code changelog.
* Fixed the conversation summary produced by `/compact` and auto-compact mangling text that contained `$` sequenceschangelog see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up /compact, on Claude Code changelog.